Phytophthora Root Rot and Aerial Blight Management
Derived from the Greek word “Plant Destroyer” the genus Phytophthora affects crops worldwide causing economic losses. Thriving in wet conditions, it is a very fast moving pathogen to susceptible crops. Phytophthora is being classified as a water mold and more related to algae then fungi. Overwintering as chlamydospores, oospores or sporangia that can persist and survive in the soil for years. The chlamydospores are produced asexually and can directly produce sporangia which release zoospores that swim through water to reinfect plants with ease. The thick walled oospores also produce sporangia which release swimming zoospores that enable spread under idea temperatures and moist, wet conditions. Spores are disseminated by water, rain, irrigation runoff, by humans and even wildlife such as snails. In greenhouses, shorefly and fungus gnat larvae can carry chlamydospores.There are more than 60 recognized Phytophthora species; at least 10 have been reported on potted plants. Many Phytophthora species are specific to common plant genera: azalea, bacopa, calibrachoa, dogwood, gerbera, lavender, pansy, petunia, poinsettia, rhododendron, vinca, and many herbaceous perennials and vegetable crops, particularly tomato.
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Phytophthora on Rhododendron, APS net |
Phytophthora
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Phytophthora root rot in Verbena |
Control options
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Phytophthora sporulation on tomato leaves |
Products for Phytophthora must be carefully chosen and rotated, due to resistance reported among some Phytophthora species. To reduce further resistance, rotation with other MOA products will improve performance. For aerial Phytophthora, foliar sprays are recommended. While the table below is provided as a summary, growers must read and follow the entire pesticide label. Products other than those mentioned may be safe, legal and effective. Not all products may be registered for use in all states. Contact GGSPro as needed for further guidance.
There are several choices of chemical and biofungicides labeled for Phytophthora when applied as drenches. When selecting fungicides, plant age, plant safety, disease pressure, rate, soil moisture and MOA should be assessed prior to using. The amount of drench volume is dictated by pot size and reapplication intervals as well as REI (reentry interval) are dictated by the product label. Most fungicide labels allowing making 2 applications before rotation to another MOA. Biological fungicides always must be applied preventatively as they have no curative properties. For growers who prefer the microbial fungicide approach, a trend of using a chemical fungicide initially to eliminate any potential soil pathogens and follow up with a biological fungicide a week or two later has provided good results. Depending on the microbial fungicide chosen, reapplications may be needed every 2-3 weeks while others can last up to 12 weeks. All labels must be examined carefully for crops being treated and application intervals.
Bring Down the Intensity this Spring with Shade
Plan to shade your crops and spare them, and yourself, the pain of sunburned foliage. Greenhouse operations can get tense in early spring as the intensity of the workload, space crunches, and insect populations all start to build. The increasing intensity of the sunlight can also be anticipated. Each spring GGSPro sees examples of sunburned crops during this early spring transition. Below are some tips to help you avoid the setbacks and costs of a sunburned crop.
Timing the Shade
In the early spring light levels increase rapidly. The more northern the location, the more rapidly the daylength increases over the spring months. At the same time as the duration is increasing, the intensity of the light is also increasing. The cumulative effect is calculated in the Daily Light Integral (DLI). Mapping DLI data by month shows the seasonal progression, as illustrated below from the work of Dr. Jim Faust’s lab at Clemson University.
These data can be used as simple guides for shading decisions, even if over simplified. Deep shade plants and many ferns are best shaded at DLIs in the 30-35 range (Kelly green). Shading should be applied over sun-sensitive and light shade loving crops when your location falls into the range of 35-40 DLI (lime green) in the maps. Most sun-loving plants will benefit from 30% shade at DLIs of 40 and above (yellow to orange shades). Remove the shade when the DLI falls below the trigger level you used in putting it on. These guides are perhaps over-simplified but provide a starting point for planning and scheduling. Note that the light level in the maps can be, and normally are, significantly reduced inside the greenhouse by the glazing, settled dust and pollen, and overhead infrastructure.
An Aphid BCA Guide for Dummies
Available in every bookstore or on the internet are the famous “For Dummies” reference books, helping readers with non-intimidating instructions on various topics. Discussed in this article today is the GGSPro version of “An Aphid BCA for Dummies.” BCA stands for Biological Control Agents. Successful pest control with predatory insects is possible, but sometimes, when aphids will not yield to BCAs alone, compatible pesticides can be used without crashing an entire BCA program.Before starting BCAs for aphid control, stop pesticide applications not designated as compatible 8-weeks prior to releasing unless you are using compatible pesticides (see below). Make sure you ask your supplier for pesticide records for all incoming plant material.
Next, follow these four principles:
1.Commit time to scouting weekly with trained personnel that can correlate pest identification and risks.
2. Place BCA orders to begin releases at the beginning of production based on desired sq ft.
3. Check viability of BCAs upon arrival and release on a predetermined schedule (release frequency and rates may need to be modified depending on pest pressure development)
4. Follow up with routing scouting and evaluations and keep records.
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Aphidius wasp, aphid mummy, Aphidoletes and lacewing larvae (left to right). Photo credit: GGSPro and Cornell IPM |
The most reliable aphid parasitoids belong to the Aphidius genus. Aphidius colemani is released for smaller aphids like the green and melon aphids, while Aphidius ervi is used for larger aphids like foxglove and potato aphid. The Aphelinus abdominalis, also an aphid parasitoid species, targets larger second and third instar aphid nymphs. Both parasitoid species lay their eggs inside the aphid where it then hatches and the larvae consumes the body. The Aphidius forms a tan colored aphid mummy while the Aphelinus produces a distinctive black mummy. Releases are done on a biweekly basis until the first sighting of an aphid. Then, plan on three weekly releases before going back to biweekly releases. Ideal temperatures are 65-85oF and 70% relative humidity. Lower or higher temperatures outside this range will delay parasitoid development.
The predatory midge, Aphidoletes or the Chrysoperla carnae/rufilabris (common name - lacewing), are used for hot spot areas along with the continued parasitoid wasp releases. Both will prey on all species of aphids. Additionally, both require warm temperatures of 70-80oF and 80-90% relative humidity. Aphidoletes will enter diapause under cool temperatures and low light condition. Releases are biweekly to weekly for Chrysoperla and weekly for Aphidoletes for 3-4 weeks or as needed to clean up an infestation.
When our biological enemies do not provide adequate control, careful choices and timing of low toxicity pesticides will provide a back up to biological control. This should allow a reduction of pest reproduction so that within 1-2 weeks, a return to BCA releases is possible. The GGSPro department can provide tailored compatibility charts to reduce harmful effects on your BCA program from pesticide applications..
The safest choices typically include biological insecticides like Ancora, BotaniGard WP, Velifer, or Venerate. These can be tank-mixed with an Azadirachtin IGR (Insect Growth Regulator) like AzaGuard, Azatin O, or Molt-X. Insecticides with short residual toxicity include: Suffoil-X/Ultra-Pure Oil, Kopa/M-pede, Endeavor (spray/drench), Kontos (spray/drench), and PyGanic. Avoid tank mixing insecticides with fungicides when using BCAs because less information is available for fungicides. Try to always spray before new BCA releases rather than after. Omit use of surfactants when possible as these can have a negative impact on BCA populations.
Product Name | MOA | Size | Comments | Item Number |
---|---|---|---|---|
Apheline | SB0202-01, 30AD25 | |||
Aphidoline BioAphidoletes | SB0151-01, BB-0006, 30AA2 | |||
APHIDIUSforce C BioAphidoletes | 30AC5, BB-0005, | |||
Apheline APHIDIUSforce C | SB0102-04, 30AC10 |
Other sizes and packaging of Aphidius mixes are available. Contact GGSPro
Product Name | MOA | Size | Comments | Item Number |
---|---|---|---|---|
CHRYSOforce R | SB0301-04, 30LWB | |||
CHRYSOforce R | 30LWE |
Other sizes and packaging of Chrysoperla larvae and eggs are available. Contact GGSPro
Product Name | MOA | Size | Comments | Item Number |
---|---|---|---|---|
Ancora | 70-1166 | |||
BotaniGard WP | 70-12521 | |||
Endeavor | 70-1655 | |||
Kopa | 70-1970 | |||
Kontos | 70-19601 | |||
M-Pede | 75-10262 | |||
PyGanic 5.0 | 70-2687 | |||
Velifer | 70-9540 | |||
Venerate | 70-9461 | |||
Azatin O | 70-12301 | |||
AzaGuard | 70-1224 | |||
Molt-X | 70-2400 | |||
Suffoil-X | 70-4040 | |||
Ultra-Pure Oil | 70-21401 |
This information is intended to help reduce aphid outbreaks that may occur during implementation of BCA programs. It is the responsibility of the applicator to read and follow all label directions. Labels do change without notice. Pesticides other than those listed may be safe, legal and effective.
Preventing Disease In Propagation
Many growers start crops from unrooted cuttings. High humidity and warm temperatures in propagation promote rooting but can also promote disease. Disease progression in propagation can be swift, so it is important to recognize and treat problems quickly and consider preventative treatments.
It is the responsibility of the applicator to read and follow all label directions. Labels do change without notice. Pesticides other than those listed may be safe, legal, and effective.
Products Mentioned In This Article
Product Name | Description | Item Number |
---|---|---|
Affirm | 71-1131 | |
Badge SC | 71-1205 | |
Broadform | 71-1290 | |
Camelot O | 70-21202 | |
CapSil | 74-1541 | |
Cease | 71-13301 | |
Empress Intrinsic | 70-1510 | |
Fascination | 73-1910 | |
Fenstop | 71-14801 | |
Fosphite | 71-1520 | |
Grotto | 71-2030 | |
Kleengrow | 74-21101 | |
Mural | 71-1690 | |
Pageant Intrinsic | 71-26801 | |
Palladium | 71-2685 | |
Phostrol | 71-2725 | |
Phyton 35 | 71-2732 | |
Protect DF | 71-2748 | |
SaniDate 5.0 | 71-35001 | |
Segovis | 71-3100 | |
Segway O | 71-31102 | |
Stargus | 71-2950 | |
Strip-it Pro | 74-2124 | |
Triathlon BA | 71-3040 | |
Zerotol 2.0 | 71-35501 |
The Relationship Between Water Quality and Fertilizer Programs
The Importance of Water Testing
Testing your irrigation water can help determine an appropriate fertilizer program that sufficiently meets nutritional requirements while managing optimal substrate media pH. There are many labs available that offer water quality testing; regardless of the lab you choose, make sure some specific horticultural parameters are measured. These include pH, alkalinity, electrical conductivity (EC), primary (nitrogen, phosphorus, potassium) and secondary (calcium, magnesium, sulfur) plant macronutrients, as well as micronutrients such as iron. Sodium and chloride, which can be negative to plant growth in large quantities, are also valuable to measure. The quality of your “clear water” or water directly from your main irrigation source (wells, ponds, city water, etc.) without any additional inputs (fertilizer, acids, bases) should be determined year to year as water quality can change over time. At a minimum, it is a good idea to have your water tested annually.
Alkalinity and Substrate pH
Alkalinity is a measure of the dissolved bicarbonates and carbonates (calcium, magnesium, and sodium) in water. More simply put, alkalinity can be seen as a fertilizer salt that is not taken up by the plant that makes a critical difference in the availability of other plant essential nutrients by altering the pH of the growing media. These carbonate species create a basic environment in the media, the higher the alkalinity, the greater the increase in media pH over time. Alkalinity can also be described as buffering capacity, or resistance to pH change. Low alkalinity water offers little or no resistance to pH changes coming from acids (sulfuric acid) and fertilizers. High alkalinity water overwhelms the effects of the acids and bases and becomes the controlling factor of media pH.
Fertilizer Rotation
Fertilizers can have a significant impact on raising or lowering substrate pH. The relative “acid forming” or “basic forming” ability of a given fertilizer is primarily determined by the percentage of ammonium to nitrate in the fertilizer. For example, fertilizers with high amounts of ammonium forms of nitrogen (21-7-7) are considered acid forming fertilizers, whereas fertilizers containing predominately nitrate forms of nitrogen (15-0-15) are considered basic forming. The relative acid/basic forming ability of a fertilizer can typically be found on most fertilizer labels below the guaranteed analysis (Figure 1). Please reference Table 1 for examples of acid and basic forming fertilizers.
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Figure 1: Example fertilizer label for Jack's 20-10-20 |
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Figure 2: Iron deficiency due to high soil pH in calibrachoa |
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Figure 3: Iron and manganese toxicity due to low soil pH in geranium |
Adjusting Substrate pH with Acid
For water with alkalinity greater than 150 ppm CaCO3, injection of technical grade sulfuric acid is recommended to neutralize alkalinity and help keep media pH within the optimum range. Sulfuric acid may be added to most acid forming fertilizers (20-10-20 or 21-5-20) but is not compatible with any fertilizer containing calcium (15-0-15, 15-0-0), which are typically basic forming as well. Reference Table 3 for rates of continuous sulfuric acid injection based on alkalinity level. Please contact GGSPro for recommended rates when using other types of acids (phosphoric, citric), suggestions on where to have your water tested, or if you have any questions on fertilizer rotation programs.
Item Description | Item Number(s) | |
---|---|---|
20-10-20 (25lb bag) | 333614, 31-140200, 67-2316 | |
15-0-15 (25lb bag) | 33626, 31-140100, 67-2340 | |
21-5-20 (25lb bag) | 33602, 31-140306, 67-2308 | |
Sulfuric Acid (1 gal) | 75-5030 | |
Jack's Potassium Bicarbonate (1lb, 25lb) | 91-2190, 91-2191 | |
BioSafe CalOx (2.5 gal) | 75-0525 |
Poinsettias - Tips for End of Season Success
This is the time of year where poinsettia growth has come to a crawl, and bract develop is in full swing. Bract development and overall poinsettia health during the late season can be managed through a combination of cultural and chemical practices. This article will outline some techniques and considerations for ensuring end of season poinsettia quality.
Bract Development and Temperature
Temperature has a direct effect on bract expansion, color, maturity, and durability. Night temperatures are critical for bract expansion, with 65-68°F being ideal for most varieties. Higher night temperatures can encourage weak bracts, dull color, bract edge problems, and foliar diseases. Night temperatures that are too cool can cause bracts not to size up properly. White flowering varieties can also look green or yellow if night temperatures are too cool. Day temperatures should be kept relatively cool to reduce stretch and increase stem strength.
Average daily temperature (ADT) has the largest impact on the rate of bract expansion and saleable color date. The stage of bract development is the best indicator of when to change temperature requirements (Table 1). Stage 3 should begin when bracts are ~75% of finished size. Stage 4 represents the time when bracts are nearly fully expanded or at saleable quality. For example, early flowering varieties may enter stages 3 and 4 up to 2 weeks earlier than Table 1 indicates. Temperatures below 60°F in stage 4 can increase the risk of Botrytis on bracts. Maintaining dry air during the last stage when the coolest temperatures occur may be difficult with reduced heat. Cooler air temperatures increase the relative humidity in the plant canopy, which in turn makes condensation more likely. Free moisture on plant surfaces favors Botrytis development.
Average daily temperature (ADT) has the largest impact on the rate of bract expansion and saleable color date. The stage of bract development is the best indicator of when to change temperature requirements (Table 1). Stage 3 should begin when bracts are ~75% of finished size. Stage 4 represents the time when bracts are nearly fully expanded or at saleable quality. For example, early flowering varieties may enter stages 3 and 4 up to 2 weeks earlier than Table 1 indicates. Temperatures below 60°F in stage 4 can increase the risk of Botrytis on bracts. Maintaining dry air during the last stage when the coolest temperatures occur may be difficult with reduced heat. Cooler air temperatures increase the relative humidity in the plant canopy, which in turn makes condensation more likely. Free moisture on plant surfaces favors Botrytis development.
Maintaining Bract Health
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Figure 1. Bract edge burn |
During the end of the season, healthy bract development is key to a quality product and long-term shelf-life. The biggest issues to look out for is Botrytis and bract edge burn, which can go hand in hand. Botrytis is a quickly spreading fungal pathogen that can propagate in damaged material caused by bract edge burn. Bract edge burn is caused by a calcium deficiency. Both of these issues can be prevented by using foliar applications of calcium and fungicides. We recommend weekly sprays with calcium chloride dihydrate rather than calcium nitrate, because calcium nitrate can occasionally cause additional bract damage. Weekly foliar sprays of calcium chloride dihydrate at 0.5 oz per 3 gal or 16 oz per 100 gal should be applied at onset of bract color. Affirm WDG, Astun, Medallion WDG, Palladium, or Spirato GHN are all effective, bract safe options for preventing and controlling Botrytis. All of these
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Figure 2. Poinsettia bract with Botrytis |
applications should be used in conjunction with a surfactant such as CapSil (¼ tsp per gal or 4 oz per 100 gal) to reduce any potential for residues. CapSil should not be applied more than once per week during bract development.
Increasing Bract Size with Fascination
Inadequate bract expansion can be caused by a number of reasons including but not limited to: a
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Figure 3. Spikey bract effect with Fascination spray |
Nutrition
Once poinsettias have essentially stopped vegetative growth and put their efforts in flowering, their overall nutrient requirements should be cut in half. Applying too much fertilizer during the bract development stage can lead to off colored bracts, salt stress, and disease issues such as Botrytis and Pythium. Please refer to Table 2 for general recommended feed rates based on dates during the late season.
*All of these recommendations are based on top irrigation. For sub-irrigation, typically ½ as much fertilizer is used. Early cultivars go to clear water ~7-10 days earlier. The recommended schedule will need to adjusted if black clothing plants.
Nutrient deficiencies that do occur during the later portion of the season need to be corrected immediately to prevent a decrease in plant quality. Most of these issues can be prevented by making sure your crop is appropriately fed and soil pH is in the correct range leading into flower. We recommend testing your tissue and soil prior to first color in order to correct any issues before bracts begin developing. The most common deficiencies typically fall under the category of molybdenum (Mo), manganese (Mn), magnesium (Mg), iron (Fe), and calcium (Ca). Mn, Mg, and Fe will increase in availability to the plant as soil pH goes down, while Mo and Ca will decrease in solubility. Utilizing a micronutrient package such as S.T.E.M. or M.O.S.T. in combination with adjusting soil pH within 6.0 to 6.5 can help correct all of these deficiencies except Ca. Calcium deficiencies can be corrected by using a calcium containing fertilizer such
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Figure 4. Pythium root rot causing plant wilting |
Late Season Pythium
There are various Pythium species that can cause root rot issues throughout the season. Most often, we can prevent root rot by supplying the appropriate concentration of fertilizer based on the stage of growth as described above and maintaining an appropriate irrigation frequency. Applying high amounts of fertilizer can lead to salt stress and damaged root systems. These conditions are ideal for Pythium to colonize and overtake the plant. Pythium can also be prevented with scheduled fungicidal drenches. Table 3 shows a recommended drench program for preventing root rot issues throughout the season.
Product Name | Item Number | |
---|---|---|
Affirm WDG | 71-1129 | |
Astun | 71-1190 | |
Medallion WDG | 71-16502 | |
Palladium | 71-2685 | |
Spirato GHN | 71-2948 | |
Banrot 40 WP | 71-1210 | |
Fenstop | 71-14801 | |
Segway O | 71-31101 | |
Subdue Maxx | 71-2979 | |
Terrazole L | 71-3025 | |
Terrazole WP | 3183862 | |
Truban 25 EC | 71-3070 | |
Fascination | 73-1910 | |
CapSil | 74-1541 | |
Jack's 15-0-15 | 33627 | |
Peters ICL 15-0-15 | 67-2340 | |
Plantex 15-0-15 | 31-140100 | |
S.T.E.M. | 67-2344 | |
M.O.I.S.T. | 33633 | |
Calcium chloride dihygrate | 35315 |
Heat Stress in Plants
All good things are best when used in moderation, as the saying goes. That is certainly true of heat in the summer, as we can all attest. As the temperatures soar plants can take a turn for the worse, a condition generally termed ‘heat stress’. Several common crops cultivated over the summer season provide well-known examples of the effects of non-lethal heat stress. Tomato crops set fruit less efficiently, poinsettias![]() |
Heat distortion of chrysanthemum foliage. |
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Lack of chlorophyll due to heat stress in geranium. |
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From: Reducing Heat Stress to Container-Grown Plants, Kentucky Cooperative Extension Circular HO-119 written by Dewayne L. Ingram, John Ruter and Chris A. Martin, 2017. |
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Re-growth of the roots on one side of the container and death of roots on the other side as the sun angle changes with the season. |
Referenced Products | Package Size | Item Number |
---|---|---|
Calcium chloride dihydrate | 35315, 35316, 35317 | |
AgSil 16H | 67-1000 | |
Sil-Matrix | 71-2940 |
1Reducing Heat Stress to Container-Grown Plants, Kentucky Cooperative Extension Circular HO-119 written by Dewayne L. Ingram, John Ruter and Chris A. Martin, 2017.
2 Ingram, D.L., J. Ruter, and C.A. Martin’s 2015 Review at: https://journals.ashs.org/hortsci/view/journals/hortsci/50/4/article-p530.xml
Fall Pansies - Fighting Black Root Rot and Phytophthora
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Pansy, Thielaviopsis |
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Pansy, Anthracnose (Colletotrichum sp.) |
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Pansy, Cercospora |
Apply as soil drenches except as noted.
Fungicide | MOA | Comments | Item Number |
---|---|---|---|
Thielaviopsis | |||
Affirm | 71-1129 | ||
Cleary’s 3336 EG | 71-2550 | ||
Cleary’s 3336 F | 71-2575 | ||
Medallion | 71-16502 | ||
Mural | 71-1690 | ||
OHP 6672 F | 71-2670 | ||
OHP 6672 WSP | 71-2672 | ||
Orkestra Intrinsic | 71-2200 | ||
Rootshield Plus G | 71-27911 | ||
Rootshield Plus WP | 71-27951 | ||
Spirato GHN | 71-1570 |
Fungicide | MOA | P= Pythium Ph= Phytophthora | Comments | Item Number |
---|---|---|---|---|
Actinovate SP | 71-1118 | |||
Adorn | 71-1130 | |||
Areca | 71-1180 | |||
Aliette | 71-11352 | |||
Banrot | 71-1210 | |||
Broadform | 72-1290 | |||
Fenstop | 71-14801 | |||
Fosphite | 71-1520 | |||
Heritage | 71-1400 | |||
Kleengrow | 74-21151 | |||
Micora | 71-1655 | |||
Orkestra Intrinsic | 71-2200 | |||
Orvego | 71-2300 | |||
Phostrol | 71-1520 | |||
Rootshield G | 0 | |||
Rootshield WP | 71-27901 | |||
Rootshield Plus G | 71-27911 | |||
Rootshield Plus WP | 71-27951 | |||
Segovis | 71-3100 | |||
Segway | 71-31101 | |||
Stature SC | 71-14652 | |||
Subdue MAXX | 71-2978 | |||
Terrazole L | 71-3025 | |||
Truban EC | 71-3070 | |||
Truban WP | 71-3065 |
Products for Common Pansies Foliar Diseases
Fungicide | MOA | Anthracnose | Botrytis | Cercospora | Item Number |
---|---|---|---|---|---|
Affirm | 71-1129 | ||||
Astun | 71-1190 | ||||
BotryStop | 71-1260 | ||||
Broadform | 71-1290 | ||||
Camelot O | 70-21202 | ||||
Cease | 71-13301 | ||||
Daconil Ultrex | 71-1420 | ||||
Daconil Weatherstik | 3117025 | ||||
Eagle | 71-1435 | ||||
Fame | 71-1505 | ||||
Grotto | 71-2030 | ||||
Heritage | 71-1400 | ||||
Kalmor | 71-2050 | ||||
Medallion | 71-16502 | ||||
Mural | 71-1690 | ||||
Nordox | 71-1700 | ||||
Orkestra Intrinsic | 71-2200 | ||||
Pageant Intrinsic | 71-26801 | ||||
Palladium | 71-2685 | ||||
Phyton 35 | 71-2737 | ||||
Protect DF | 71-2748 | ||||
Spirato GHN | 71-1570 | ||||
Triathlon BA | 71-3040 | ||||
Trigo | 70-3035 | ||||
Zerotol 2.0 | 71-35501 |
Read and follow all label directions. The label is the law! Products other than those mentioned may also be safe and effective. Some pesticides may be restricted-use or unregistered in certain states.
Insect Pest Control Roulette
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Figure 1 - Example of Incomplete Metamorphosis |
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Figure 2 - Example of Complete Metamorphosis |
Common Name | Life Cycle* | Damage | Chemical Control | Item Number |
---|---|---|---|---|
Aphids | 70-1161 (64 oz) 70-2630 (qt) 70-85221 (qt) | |||
Beetles | 70-14091 (gal) 70-2331 (pt) 70-2975 (64 oz) | |||
Grasshoppers | 71-1105 (lb) 70-2655 (gal) 70-85221 (qt) | |||
Moths | 70-1450 (lb) 70-2655 (gal) 70-9461 (qt) | |||
Plant Bugs | 70-1161 (64 oz) 70-2630 (qt) 70-2655 (gal) | |||
Plant Hoppers (including leafhoppers) | 70-14091 (gal) 70-1700 (8 oz) 70-85221 (qt) | |||
Sawflies | 70-1365 (qt) 70-2655 (gal) 70-2975 (64 oz) | |||
Spider Mites | 70-30151 (pt) 70-3045 (16 oz) 70-4040 (2.5 gal) | |||
Stink Bugs | 70-1232 (qt) 70-2687 (qt) 70-2975 (64 oz) | |||
Thrips | 70-2331 (pt) 70-2630 (qt) 70-2655 (gal) | |||
Weevils | 70-1700 (8 oz) 70-2331 (pt) 70-2975 (64 oz) | |||
Whiteflies | 70-1166 (lb) 70-2630 (qt) 70-85221 (qt) |
Extending Shelf Life and Marketability of Spring Plants
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Figure 1. Calibrachoa is an example of a cold tolerant plant |
· Argyranthemum
The ABCs of BCAs
Worker safety with BCAs can be seen in their application methods. With typical BCA applications, workers can directly handle BCA materials with no physical or health safety concerns. BCAs are usually highly species specific when choosing their targets, and simply migrate or die when their prey targets are no longer found. BCAs must be native to North America to be sold in the US, meaning introduction of an invasive species is not a concern. Pest specific targeting also leaves bees unaffected by most BCAs. Finally, pesticides run the risk of facing developing resistance in their target pests. Most pesticide programs recommend regular rotations to avoid overexposure of a single mode of action. For BCAs, there really is no developing a resistance to predation.
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Figure 1. A parasitic wasp (Eretmocerus eremicus) laying eggs under whitefly pupae |
Target Pest | Type of BCA |
Aphids | Parasitic wasps, lacewing, and larvae (bulk release) |
Black Vine Weevil & White Grubs | Nematodes |
Fungus Gnats | Nematodes, predatory beetles, and mites |
Leafminers | Parasitic wasps |
Mealybugs | Predatory beetles and larvae |
Spider Mites | Predatory mites |
Thrips | Nematodes, predatory beetles, and mites |
Whiteflies | Predatory bugs, beetles, parasitic wasps, and mites |
Figure 2. Sachets on sticks containing predatory mites used for annual young plant pest management | Figure 3. Bulk release bottle of Aphidius ervi, a predatory wasp used for aphid control |
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Figure 4. Bulk release material containing predatory mites for whitefly and thrips control | Figure 5. Beneficial nematodes used for fungus gnat and thrips control |
Plant Lighting – Introduction into Supplemental and Sole-Source Lighting
Introducing Lighting UnitsThe previous lighting article focused on photoperiodic lighting. This article will focus on supplemental and sole-source lighting strategies. Utilizing these lighting techniques requires thorough understanding of what light is and how it is quantified. There are some standardized terms and units that are used in today’s industry, which can help you maximize the benefits of plant lighting (Table 1).
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Fig1. Photosynthetic Active Radiation (PAR) Spectrum (400-700nm) Photo provided by Dr. Erik Runkle, MSU |
Light is a form of energy measured in photons. Photons can travel in different wavelengths and these wavelengths are measured in nanometers (nm). The wavelength that light travels in can be broadly described as light quality. Humans can visibly see photons traveling in wavelengths ranging from 380-770 nm (i.e. the visible light spectrum). Within this range, plants utilize photons within 400-700 nm (light qualities of blue to far-red) for photosynthesis (Fig. 1). We call light within this range photosynthetic active radiation (PAR).
It is important for growers to know how much light plants receive for a given area, so light intensity measurements are typically reported as a density (amount of light given off every second per square meter of growing space). We call this photosynthetic photon flux density (PPFD).
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Fig 2. Supplemental lighting during winter months for young plant production |
Supplemental lighting is the use of artificial light to supplement PPFD provided by sunlight. The purpose of supplemental lighting is to add additional light at intensities high enough to increase photosynthesis and improve plant quality in situations where sunlight is limited. During periods where light levels are minimal such as the winter (due to a lower photoperiod) or cloudy days, supplemental lighting can provide additional PPFD to plants to carry on with adequate rates of development.
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Fig 3. Indoor vertical farm with sole-source lighting |
Sole-source lighting is the use of artificial light without additional PPFD from sunlight to produce any or all stages of a crop. This form of lighting application has been utilized in environmental controlled settings such as factory farms, indoor grow operations, and vertical farms. This is the most expensive plant lighting application. These costs are attributed to high capital and installation costs of the light modules themselves and electrical costs required to operate the lights on a daily basis. For supplemental and sole-source lighting applications, achieving a target DLI is very important. The target DLI a grower should strive for is crop and crop stage specific (Table 2). DLI is essentially the total amount of PAR light one square meter of growing space receives over a single day (mol∙m-2∙d-1).
Griffin offers a wide range of lighting products and services to meet all your photoperiodic, supplemental, and sole-source lighting needs. Please reach out to GGSPro or the Griffin CEA division with any questions or inquiries you may have regarding plant lighting.
Plant Lighting - Introduction into Photoperiodic Lighting
OverviewLight is an essential input for driving plant growth and producing a high-quality product. The major light sources for growing plants include sunlight and plant lighting technology. Growers can use plant lighting in three major ways:
• Photoperiodic Lighting - manipulating vegetative and reproductive stages of plant development through day/night length control
• Supplemental Lighting - adding additional light to increase total crop photosynthesis and quality
• Sole-Source Lighting - growing plants in completely artificial light
This article will focus on photoperiodic lighting and how it is utilized in plant production. There will be a follow-up article on utilizing supplemental and sole-source lighting over the coming year.
Photoperiodic Lighting
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Fig 1. Photoperiodic lighting to keep young plants vegetative |
A majority of plants we grow are separated into three photoperiodic requirement categories: plants requiring daylengths less than a given amount of time are short-day (SD), plants requiring daylengths more than a given amount of time are long-day (LD), and plants that do not require a given daylength to show a response are day-neutral (DN). A majority of LD plants require greater than 12 hours of daylength to initiate flowering while most SD plants require less than 12 hours to initiate flowering. Photoperiod requirements can be species specific and even vary between varieties.
Examples of Photoperiodic Control in Production
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Fig 2. Black cloth used to force SD plants into flower |
Scheduling plants is vital to meet consumer needs. There are times when the natural photoperiod is greater than 12 hours and growers need to force SD plants into flower. Growers can decrease natural photoperiod by pulling black cloth over the crop in the morning and evening hours on a daily basis. This will extend the “nighttime” period and force SD plants into flower.
Griffin offers a wide range of lighting products and services to meet all your photoperiodic, supplemental, and sole-source lighting needs. Please reach out to GGSPro or the Griffin CEA division with any questions or inquiries you may have regarding plant lighting.
New Products from the Softer Side of Pest Control
The trend in new pesticide introductions for commercial greenhouse and nursery operations is towards “softer” pesticides, many of which are approved for organic production. Many consumers and producers are asking for these types of products and the market has responded to this demand in a significant way. A few notable introductions into this category of pesticides are discussed below.Sil-Matrix is based on a liquid concentrate of potassium silicate. It is an EPA registered fungicide, insecticide and miticide. Silicon research is being conducted in a number of places and as a result many plant health benefits have been described. Sil-Matrix is applied as a foliar spray for the control of aphids, spider mites and whiteflies as well as important foliar diseases such as Botrytis and powdery mildew. It is labeled for use on ornamentals and many edible crops including certain vegetables, berries, vines and fruit trees. The addition of a high quality surfactant such as CapSil improves coverage and reduces visible residue on plant surfaces. Sil-Matrix is OMRI listed and benefits from a 4 hr REI and can be used up to the day of harvest.
Item 71-2940 Size 2.5 gal
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Spider mite, 5 days after Velifer treatment - Photo credit BASF |
Item: 70-9540 Size: quart
FireWorxx is a fast acting, non-selective broadleaf weed, grass, algae and moss killer. On a warm sunny day results can be seen in a few hours, but never longer than 2 days. It can be used in and around ornamentals and edible crops, so long as all contact with desirable foliage is avoided. FireWorxx can also be added at a 1% rate to improve the performance of other herbicides such as glyphosate, (Round-Up, etc) and glufosinate, (Cheetah Pro, Finale). FireWorxx is an OMRI listed product with a 12 hr REI.
Item: 72-1608 Size: gal
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Dahlia, Powdery Mildew |
Item: 71-1455 Size: quart
Algae Is A Slippery Slope
Algae on a walkway |
Preventing establishment of algae is the best practice, after it takes up residence, a grower is sliding down that metaphorical slippery slope. It can be hard to reign in the green slime. Prevention begins when the system or structure is recently cleaned and sanitized, or is new in the case of soil-less media or rockwool cubes. Algae reproduces by sporulation and by simple cell division. Spores can be airborne and can cling to greenhouse surfaces, including the greenhouse plastic, leading to recurring issues. Thorough cleaning using an acid or chlorine-based product, followed by a disinfecting sanitizer is necessary to eliminate the spores on surfaces. Request the GGSPro bulletin: Hard Surface Sanitation Practices for more information.
Algae on a basil float bed |
Algae in the water system the leading cause of algae on the soil surface and provides a continual source of algal inoculum for hydroponic systems, drip irrigation systems, walkways and other greenhouse surfaces. Water systems are best cleaned when no plants are on the line or in the greenhouse. To break down the algae, biofilms, and mineral deposits that build up even when ‘clean’ water is used, strong cleaners are required. An empty production area is also best for cleaning surfaces, floors and bench supports. For some growers seasonal breaks provide the perfect opportunity for cleaning and sanitation. For growers in perpetual production, it is worth the effort to make a day, or even part of a day to clean the irrigation system and production area surfaces.
Product | Rate | Use Notes | Item Number |
---|---|---|---|
Cleaners | |||
GreenClean Acid Cleaner | 74-2040 | ||
SaniDate 12.0 OMRI listed | 71-35351 | ||
Strip-It Pro | 74-2125 |
Product | Rate | Use Notes | Item Number |
---|---|---|---|
Cleaners | |||
GreenClean Acid Cleaner | 74-2040 | ||
GreenClean Alkaline Cleaner | 74-2045 | ||
GreenClean Pro OMRI listed | 74-20521 | ||
Horti-Klor | 74-2105 | ||
Strip-It Pro | 74-2125 |
Treat floors, hydroponic troughs of channels, sidewalls, benches, and supports. Rinse copper or aluminum, which are soft metals as soon as possible. These are strong cleaners, obey all label precautions and personal protection equipment requirements.
Once algae has been dealt a deadly blow, a sanitizer should be used to finish the job by disinfecting the cleaned system or surface, see chart below.
When algae control is needed in and around crops, many of these same products are used for preventative maintenance against algae, either periodically, or by continuous injection in the water. Furthermore, SaniDate12.0 or ZeroTol 2.0 can be used to clean irrigation lines while ‘in use’. After soaking with one of these oxidizers, the bulk of the algae and sanitizer is flushed through an opened drain valve before irrigation, since it will not be fully broken down.
Product | Rate | Use Notes | Item Number |
---|---|---|---|
Cleaners | |||
Eco-Clean | 74-2040 | ||
Kleengrow | 74-2045 | ||
SaniDate 5.0 OMRI listed | 74-20521 | ||
SaniDate 12.0 OMRI listed | 74-2105 | ||
ZeroTol 2.0 OMRI listed | 74-2125 |
Cyclamen Production - Plan Now to Succeed
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Rainier White Cyclamen - Syngenta Flowers |
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Calcium Deficiency |
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Fusarium |
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Erwinia |
Product Name | Item Number | |
---|---|---|
14-5-38 | JP14538 | |
15-0-15 | 33627 | |
21-5-20 | 33602 | |
Affirm | 71-1131 | |
Astun | 71-1190 | |
Broadform | 71-1290 | |
Cease | 71-13301 | |
Camelot O | 70-21202 | |
Cleary's 3336 | 71-2575 | |
Empress Intrinsic | 70-1510 | |
Heritage | 71-1400 | |
Kalmor | 71-2050 | |
Medallion | 71-16502 | |
Mural | 71-1690 | |
Nordox | 71-1700 | |
Orkestra Intrinsic | 71-2200 | |
Pageant Intrinsic | 71-26801 | |
Palladium | 71-2685 | |
Phyton 35 | 71-2732 | |
Spirato GHN | 71-2948 | |
Triathlon BA | 71-3040 |
Garden Mum Disease, Insect, and Mite Control Options
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Chrysanthemum White Rust |
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Bacterial Leaf Spot |
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Pythium Root Rot |
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Aerial Rhizoctonia Web Blight |
Caterpillars- Conserve (5), DiPel Pro DF (11A), Mainspring GNL (28), Pedestal (15), and Tristar (4A) are effective and have favorable bee safety profiles- (check EPA bee box provisions on the Mainspring GNL label for specific instructions). All of these products benefit from the addition of CapSil.
Leafhoppers- Altus (4D), Kontos (spray or drench) (23), Sanmite SC (21A) and Tristar (4A). Some of these products have specific instructions regarding pollinator safety. All of these foliar spray products benefit from the addition of CapSil.
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Blotch Leafminer |
Spider Mites- Akari (21A), Avid (6), Kontos (drench only) (28), Minx 2 (6), Sanmite SC (21A), Savate (formerly Judo) (23), Shuttle O (20B), and Sultan (25). Some of these products have specific instructions regarding pollinator safety. All of these foliar spray products benefit from the addition of CapSil.
Thrips- Avid (6) or Minx 2 (6) tank mixed with Azatin O (UN), AzaGuard (UN) or Molt-X (UN); Hachi-Hachi SC (21A), Kontos (drench only) (23), Mainspring GNL (28), Mesurol (1A), Pedestal (15), and Tristar (max label rate only) (4A). Hachi-Hachi SC and Mesurol are highly toxic to bees and should not be used immediately prior to or during open bloom. Mainspring GNL has specific bee safety instructions in the EPA bee box. All of these foliar spray products benefit from the addition of CapSil.
Not all products are registered in all states. Some pesticides are restricted use in some state or regions and not others. It is the responsibility of the applicator to read and follow all label directions.
Product Name | Mode of Action (MOA) | Item Number | |
---|---|---|---|
Disease Control Options | |||
Affirm | 71-1131 | ||
Banrot 40 WP | 71-1210 | ||
Broadform | 71-1290 | ||
Cease | 71-13301 | ||
Daconil Weather-stik | 71-1420 | ||
Eagle 20 EW | 71-1435 | ||
Fame SC | 71-1505 | ||
Heritage | 71-1400 | ||
Kalmor | 71-2050 | ||
Medallion | 71-16502 | ||
Mural | 71-1690 | ||
Nordox 75 WG | 71-1700 | ||
Orkestra Intrinsic | 71-2200 | ||
Pageant Intrinsic WG | 71-26801 | ||
Palladium WDG | 71-2685 | ||
Phyton 35 | 71-2732 | ||
PreFence | 71-2771 | ||
Protect DF | 71-2748 | ||
Rootshield Plus G | 71-27921 | ||
Rootshield Plus WP | 71-27961 | ||
Segway | 71-31101 | ||
Spirato GHN | 71-2948 | ||
Terrazole L | 71-3025 | ||
Triathlon BA | 71-3040 | ||
Truban 25 EC | 71-3070 | ||
Truban 30 WP | 71-3065 | ||
Insect and Pest Control Options | |||
Altus | 70-1161 | ||
Akari | 70-1160 | ||
Aria WDG | 70-3399 | ||
Avalon Golf & Nursery | 70-1210 | ||
Avid 0.15 EC | 70-1185 | ||
AzaGuard EC | 70-1224 | ||
Azatin O | 70-12301 | ||
Citation WSP | 70-13501 | ||
Conserve SC | 70-1365 | ||
DiPel Pro DF | 70-1450 | ||
Endeavor WDG | 70-1660 | ||
Hachi-Hachi SC | 70-1795 | ||
Kontos | 70-19601 | ||
Mainspring GNL | 70-2331 | ||
Mesurol 75 WP | 70-2325 | ||
Minx 2 | 70-2398 | ||
Molt-X | 70-2400 | ||
Pedestal SC | 70-2950 | ||
Sanmite SC | 70-2915 | ||
Savate | 70-2980 | ||
Shuttle O | 70-30151 | ||
Sultan | 70-3045 | ||
Tristar 8.5 SL | 70-85221 | ||
Ventigra | 70-9550 | ||
Surfactant | |||
Capsil | 74-1541 |
Defense Against Fusarium Wilt in Chrysanthemum
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Symptoms of Fusarium Wilting in Chrythsanthemum |
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Vascular Streaking within Stems |
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1 Advance Fusarium revealing White Mold on Stems |
Chemicals Labeled for Fusarium Prevention
Product | Size | Item Number |
---|---|---|
Cleary’s 3336 F | 71-2575, 71-2585 | |
Cleary’s 3336 EG | 71-2550 | |
Empress Intrinsic | 70-1501 | |
Fame G | 71-1500 | |
Fame SC | 71-1505 | |
Heritage | 71-1404, 71-1400 | |
Medallion WDG | 71-16502 | |
Mural WG | 71-1690 | |
OHP 6672 L | 71-2670 | |
OHP 6672 WSP | 71-2672 | |
Orkestra Intrinsic | 71-2200 | |
Pageant Intrinsic | 71-26801, 71-26821 | |
Terraguard SC | 71-3018 | |
Spirato GHN | 71-1570 | |
RootShield Plus G | 71-27911, 71-27921 | |
RootShield Plus WP | 71-27951, 71-27971 | |
PreFence | 71-2770, 71-2771 | |
PVent | 71-2775, 71-2776 | |
Greenshield II | 74-36601, 74-36611 | |
KleenGrow | 74-21151, 74-21301 | |
Strip-It Pro | 74-2125, 74-21230 |
Beautiful Disaster: How to Defend Against Spotted Lanternfly
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SLF nymphs, first instar |
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SLF nymph, fourth instar Photo credit: UMass Extension |
SLF are native to China and Vietnam and feed on more than 70 plant species as phloem feeders. They’re known to move 3-4 miles a year, mostly by being excellent hitchhikers. Therein lies the challenge: how to quarantine a pest that’s now detected in seven states (Pennsylvania, Virginia, New Jersey, Delaware, New York, Maryland and Connecticut) since its first detection in Pennsylvania in September 2014.
Adults emerge by mid-July and are exquisitely beautiful. The wings are gray with black spots at the front and speckled bands on the last 1/3 of the wings. When wings are spread, the base of the hind wings is scarlet with white spots in the front, and white with black bars at the rear. The abdomen is yellow with black bars.
Major plants at risk to SLF damage include
tree of heaven, maples, grapes, apples, hops,
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SLF adult Photo credit: Penn. Dept. of Agriculture |
Insects that resemble SLF include green stink bug nymphs and ticks. If you suspect you may have detected SFL, take a photo and send it to your state department of agriculture for verification. Keep the insect in a sealed bag and put it into the freezer.
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Green stink bug nymphs |
To limit the spread of SLF, actionable quarantine and shipping restrictions have been implemented. For details on regulatory articles, see the www.northeastipm.org or visit www.agriculture.pa.gov for information on the permit process for businesses operating within a regulated area.
Learn to identify the tree-of-heaven (Ailanthus altissima), which is used as a monitoring host tree. The SLF prefers to feed and mate on this specific tree species. To establish a trap crop for SLF, land owners should leave in place male trees that are at least 10” in trunk diameter, and clear all other male and female trees. This facilitates the use of systemic chemicals to limit the exposure of non-target organisms, as few other pests feed on these trees. Application must be repeated annually until no SFL adults are detected on a property.
Removal of trees-of-heaven is a mechanical option to eliminate breeding sites for SLF. Chemical options include spraying targeted plants mid-May through August. Systemic insecticide drenches (e.g., dinotefuran, imidacloprid) are most effective when applied in spring and early summer, before adults build up their populations. The most effective option in controlling SLF are foliar-applied chemicals that contain bifenthrin, carbaryl, dinotefuran or imidacloprid. Basal bark treatments and stump treatments with approved herbicides are among the methods available to remove unwanted trees. Contact GGSPro for more details.
It’s the responsibility of the applicator to check labels and state laws for regulated application sites. Some products may be restricted use. Always read and follow all label directions. The label is the law! Products other than those mentioned may also be safe and effective. Some pesticides may be restricted-use or unregistered in certain states.
Products for Control of SLF Adults (Apply as soil drenches)
Product | MOA | Description | Item Number |
---|---|---|---|
Mallet 2F T &O | 70-2340 | ||
Marathon 1% G | 70-23752 | ||
Safari 20SG | 70-29951 |
Products for SLF Nymphs (Apply as foliar sprays)
Product | MOA | Description | Item Number |
---|---|---|---|
Avalon Golf & Nursery Insecticide | 70-1210 | ||
Mallet 2F T &O | 70-2340 | ||
Marathon II | 70-23712 | ||
Safari 20SG | 70-29951 | ||
Sevin SL | 70-3002 | ||
Talstar Pro | 70-34052 |
Good to the Last Raindrop: How to Protect Crops Through Prolonged Wet Weather
In many parts of the country, last spring was so wet that you had to laugh to keep despair from setting in: “Some growers only had two rain storms last season. The first one lasted for 52 days and the second one only lasted for 40 days.”We kid but, of course, we know soggy spring weather is no joke. A greenhouse filled to capacity with pot-to-pot mature plants in full bloom is not a good place to ride out a long spell of cool, damp weather. Such persistent conditions can provide a launchpad for Botrytis and aerial Rhizoctonia.
There’s no time like the present to prepare for soaking spring rains. Since we can’t control the weather, the best we can do is limit the associated risks. When cloudy, wet weather sets in, disease scouting and control become top priorities.
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Botrytis on marigold |
Understanding Botrytis and aerial Rhizoctonia
Botrytis and aerial Rhizoctonia share two favorite things. The first is full greenhouses, where air movement is limited or, at worst, inadequate. The second is free moisture on leaf surfaces.Botrytis symptoms can vary in appearance due to several factors including where on the plant it occurs and the current environmental conditions. Symptoms can occur on leaves, stems, fruit, buds and blooms. Expanding brown lesions of decaying plant material are sometimes covered with white/grey spores when environmental conditions are favorable for disease development.
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Aerial Rhizoctonia on Vinca minor |
Effective fungicides are available but if the greenhouse environment isn’t also carefully managed, those products may fall short. What follows are best practices to mitigate foliar disease risk in your greenhouses.
Controlling variables in the greenhouse
It’s inevitable that, even during long wet spells, the crops will eventually need to be irrigated. The opportune time to irrigate is in the morning, giving foliage the best chance of drying by nightfall. Under these conditions, drip irrigation and sub-irrigation are greatly beneficial as they minimize wet foliage. When you’re considering irrigation equipment for the future, remember these weather patterns; the upfront cost can be a wise investment in the long run.Similarly, it may be tempting to turn the heaters off at this time of year to save fuel. However, the increased disease risk may cost more than the fuel. The cooler the air is, the less moisture it can hold. If there’s more moisture in the air than it can hold, condensation begins to form on the cooler leaf surfaces.
It’s best to maximize air movement with HAF (horizontal air flow) fans and adequate crop spacing. Doing so makes temperatures more even throughout the crops, reducing cool spots where condensation may form.
Conversely, heating the air allows it to hold more moisture and reduce condensation. Leaf wetness is the enemy when it comes to many foliar diseases. The expense of running some heat in the greenhouse is dwarfed by the potential of losing crops that are so close to the finish line.
Should you ventilate when it’s raining? If it’s raining, misting or foggy outside, it’s best to keep the greenhouse closed up and run some heat to dry the air a bit. If daytime conditions are overcast but not raining, ventilate the house to expel airborne disease spores and reduce relative humidity.
As old blooms begin to decay, they’re quickly colonized by Botrytis, which turns them into spore-making machines. Taking the time to deadhead spent blooms and remove them from the growing area is cheap insurance.
Preventive and curative fungicide options
Even with the best cultural controls, fungicides sprays are often still necessary. Having optimized the growing environment to every extent possible, it’s time to consider fungicide spray options.Any fungicides used at this stage will need to have a good record of bloom safety and leave little or no residue. Using CapSil or another high-quality surfactant will help reduce the visible residue that can be left behind. (Not all fungicides should be used with surfactants. Check the label.)
Wet sprays contribute to leaf wetness, which can be slow to dry. For short-duration rainy spells, it may be best to withhold treatment until the sun shines again. When the forecast calls for three or more consecutive rainy days, it may be best to treat anyway.
Consult the GGSPro Technical Reference Guide for a comprehensive list of fungicide options, including rates and use patterns.
Not all products are registered in all states. It is the responsibility of the applicator to read and follow all label directions, remembering that labels may change. Other products than those listed here may also be safe and effective. Rates, application methods and edible status are detailed in the product label.
Product Name | MOA | Rate/gal | Rate/100 gal | Item Number | |
---|---|---|---|---|---|
Affirm | 71-1129 | ||||
Astun | curative preventative control. | 71-1190 | |||
Broadform | surfactants. Fogging prohibited. | 71-1290 | |||
Cease | OMRI-listed. | 71-13301 | |||
Decree | Resistance has been reported. | 71-1440 | |||
Mural | surfactants. Injury observed on African violets, ferns and rex begonias. | 71-1690 | |||
Orkestra Intrinsic | surfactants. Injury observed on wintercreeper and nine-bark. Spotting has occurred on impatiens and petunias. Fogging prohibited. | 71-2200 | |||
Pageant Intrinsic | surfactants. Injury observed on wintercreeper and nine-bark. Spotting has occurred on impatiens and petunias. Fogging prohibited. | 71-26801 | |||
Palladium WDG | impatiens or NGI. Sensitivity has occurred on Superbells Coralberry Punch calibrachoa and all geraniums. | 71-2685 | |||
Triathlon BA | OMRI-listed. | 71-3040 |
Into the Great Wide Open: Tips to Transition Spring Crops from Greenhouse to Outdoors
As the greenhouse fills with new plantings and partially finished crops are screaming to be spaced, moving finished product outside can open up valuable heated space. However, moving plants outdoors early in the season comes with risks as well as potential rewards.The primary risk is, of course, cold damage due to frost or freeze. Rewards include heated space available for younger plants, better holding ability among the finished plants and stronger weather-acclimated performance for the final customer. Through careful selection of cold-tolerant plants, active management and emergency actions as needed, the risks are diminished and the rewards become a win-win for both the grower and end user.
Hardening off involves physical changes in the plant that can be seen and felt as the plant begins to acclimate to lower temperatures. These changes typically require a minimum of 7-14 days with temperatures above freezing and below 50˚F.Every plant grown in a warm greenhouse over the winter -- whether an annual, a hardy perennial or woody plant -- must be “hardened off” before exposure to the realities of early spring frosts and possible freezing temperatures. Hardening off involves physical changes in the plant that can be seen and felt as the plant begins to acclimate to lower temperatures. New leaves thicken and darken in color, and stems of new tips mature and stiffen. These changes typically require a minimum of 7-14 days with temperatures above freezing and below 50˚F. More on that below.
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Freeze damage on calibrachoa |
Cold-tough annuals and hardy perennials can be transitioned much the same way. To maintain the foliage in good condition, prevent frost exposure and frozen rootballs during the hardening time. When temperatures are mild (38-45˚F nights) plants can move directly outdoors. For temperatures of 33-37˚F, when frost is likely if the wind is calm, cover crops with row cover or frost cloth, or provide other overhead protection to prevent potential frost formation on the foliage. A cold frame also works well for this purpose.
When light freezing temperatures are expected (28-32˚F), a closed cold frame will provide a few precious degrees of warmth to plants on the ground. Frost cloth or a winter blanket, spread in mid-afternoon to trap radiant heat, will generally maintain overnight temperatures at the foliage of 3-6 degrees higher than the surrounding air, depending on the weight of the cloth. Be sure to support heavier cloth off the top of the plant canopy to reduce damage.
When repeat or hard freezes are expected, hardening can be carried out in a greenhouse maintained at 40-45˚F. When an occasional unexpected or brief freeze pops up in the forecast, growers may need to resort to emergency measures.When repeat or hard freezes are expected, hardening can be carried out in a greenhouse maintained at 40-45˚F nights. However, when the occasional unexpected and brief freeze pops up in the forecast, sometimes the protections above can’t be employed.
In this case, the grower may resort to emergency measures. The traditional action is to use overhead sprinklers to prevent freeze damage. This works because, as the water begins to freeze on the leaf, it releases a small amount of heat. As long as a thin layer of water is present, the plant will be protected from freezing, whether the water is landing directly on the foliage or on the outer layer of ice that will form over the plant. The constant freezing of water throughout the night will maintain the plants above the critical temperature.
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When using the sprinkler method, continue applying water until the protective ice melts in the morning. |
Another emergency measure that can be employed is a foliar application of a strobilurin fungicide such as Pageant or Mural (MOA 7 +11). When sprayed within 24 hours of a freeze event, these fungicides effect physiological processes in the plant, such as slowing water transpiration. This tactic can impart several degrees of cold tolerance, in addition to disease protection. Spray Pageant at 12 oz/100 gallons (3/4 tsp per gallon) or Mural at 6-8 oz/100 gallons (3/8 to 1/2 tsp per gallon).
The hardening process should be actively managed according to the weather forecast, closing and venting cold frames, or covering and uncovering as necessary to protect the plants during periods of low temperatures.
Well-hydrated plants will withstand the cold better. Desiccation is often a major contributor to cold damage. Make sure outdoor plants are well watered and the foliage is dry before temperatures drop. Once the plants are thoroughly hardened, they’ll survive exposure to cold temperatures down to the limit of their genetic tolerance. Light overhead protection during cold snaps will still produce the best foliage and quickest flowering.
Product Name | Item Number | |
---|---|---|
Pageant Intrinsic | 71-26801 | |
Mural | 71-1690 | |
Winter protection fabric* | 81-730400 | |
Heavy frost cloth* | 78-2045 |
Printable version
Geraniums: A Crop Culture Tune-Up
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Well-branched, uniform geraniums ready for retail sale |
Producing top-quality geraniums requires close attention to detail. Not everyone can do it well! But for the growers who do, their attentiveness is rewarded. Let’s review some of the finer points of geranium culture. Are there details you haven’t considered lately? Is there an opportunity to fine-tune production of your next crop?
Soil mix and pH
Soil mixes should be well drained and be maintained at a soil pH in the range of 6.6. pH control is crucial because geraniums are very susceptible to iron/manganese toxicity at a soil pH of 5.8 or lower. Monitor soil pH weekly to prevent problems before they occur.Temperature
The most economical geranium production takes place at average daily temperatures in the range of 65-70° F. Typically, this means night temperatures between 62-65° F and day temperatures in the range of 68-70° F. Crop timing for a 4.5” pot is 6-8 weeks.Although geraniums can be grown much cooler, doing so comes with some risk: The lower temperatures significantly increase crop time and raise the risk for Botrytis.
Fertilizer
Geraniums are moderate feeders. Maintain 200 ppm CLF, reducing that to 125-150 ppm as the crop approaches marketable size. This practice improves shelf life and eases the transition to be planted outdoors. Fine-tuning your geranium fertilizer program through water testing is recommended.Height control via PGRs
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Florel on geranium |
Cycocel has long been used to control height and leaf size on geraniums. Zonals generally receive 1500 ppm, while Calliope and most ivy geraniums are treated at 1000 ppm. To avoid yellowing or distorted foliage, spray Cycocel only to glisten. This approach can be used on a bi-weekly basis. Cycocel metabolizes quickly in the warmer temperatures that we often experience in late spring and summer. More frequent sprays, up to once a week, may be required.
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This trial compares the effects of Bonzi and Cycocel on geranium |
Height control without PGRs
To control geranium height without PGRs, the Morning Temperature Dip technique can be quite effective. Most plant stretch occurs during the first three hours of daylight. Beginning at first light in the greenhouse and continuing for the first three hours of the day, drop the air temperature to 5° F below the night set point. After three hours, return temperatures to their normal setting. This simple practice can greatly reduce the need for PGRs, limiting stem elongation without significantly decreasing the average daily temperature.Product Name | Description | Item Number |
---|---|---|
Bonzi | 2.5 gal | 70-1260 70-1270 |
Cycocel | 1 gal | 73-1380 73-1381 |
Florel | 1 gal | 608-395 55-100161 |
A Greenhouse Game Changer: Introducing the Bluelab 3-in-1 Pulse Meter
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Pulse meter with depth gauge Photo credit: Bluelab Corporation |
Peat, coir, composted pine bark, rockwool and mineral soils can all be tested with nearly instant results. For the greatest amount of precision, the Pulse meter offers different settings for each type of soil mix. Settings can be quickly and easily changed to efficiently test multiple media mixes.
The Pulse meter can also be used to test solutions, saving the need for an additional meter. Test results can be transferred to a Bluetooth-enabled smartphone with the help of the free Pulse mobile app. Test data is stored by the app, so growers can easily review and analyze data. The Pulse app is currently available for Android devices; support for iPhones is expected to follow sometime in 2019.
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The Pulse mobile app is currently available for Android devices. Photo credit: Bluelab Corporation |
Compared to making slurries and performing the 2:1 test, the Pulse meter is a bona fide timesaver. Testing is so fast that a large number of samples can be taken in order to get the most representative picture of what’s going on in the crop.
Calibration and cleanup are fast and easy, too. The probes are 8 inches long and come with a built-in depth gauge to ensure consistent measurements. (Note: The Pulse meter can accurately test pots 4 inches deep or deeper.) Just like the other meters from Bluelab, the Pulse meter is reliable and is backed by excellent technical support.
Bluelab Pulse Multimedia Meter
Item number: 83-2778
Blinded by the Blight: What to Do When Your Foliar Disease is Actually a Soil-Borne Pathogen
Plants are subject to an array of foliar diseases: blights, root and stem rots, bacterial infections, wilts, viruses and nematode diseases. Symptoms that appear on afflicted plants are clues, but unless a telltale sign of the causal organism is present, identification can be challenging without microscopic examination. The same goes for pathogens affecting roots.While symptoms may be visible above ground, the actual cause could be a soil-borne fungus. Let’s explore two root-root pathogens – Rhizoctonia and Phytophthora -- with the unique ability to infect plant foliage as an aerial blight, and how to tell the difference.
Real talk about Rhizoctonia
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Rhizoctonia web blight on dianthus |
Rhizoctonia doesn’t produce spores, but it can produce a survival structure known as sclerotia and it can survive in plant debris and in soil for years.
Rhizoctonia affects many plants including aster, begonia, chrysanthemum, dianthus, ferns, gerbera, impatiens, petunia, vinca and zinnia. Many herbaceous perennials and landscape plants are prone to infection, too.
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Rhizoctonia web blight on aster |
When in doubt, take a sample from the diseased plant material; place foliage and stems between two layers of wet, brown paper towel or moist, dark-colored newspaper. In both cases, the dark color enhances visibility of the mycelia, which is white. Seal the sample in a zip-top bag or salad container and store at room temperature for 36-48 hours. Examine for webbing.
All about aerial Phytophthora
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Aerial Phytophthora sporulation on tomato |
Many Phytophthora species are specific to common plant genera: azalea, bacopa, calibrachoa, dogwood, gerbera, lavender, pansy, petunia, poinsettia, rhododendron, vinca, and many herbaceous perennials and vegetable crops, particularly tomato.
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Phytophthora canker on poinsettia |
When above-ground infections occur, known as aerial Phytophthora, plants often exhibit a rapid wilt with a characteristic bleaching of leaves starting at the leaf base. Leaf spotting, leaf drop, dull-colored isolated branches/stems or stem lesions are other pathogen indicators. On some plants (e.g., tomato), whitish sporulation can be observed under high infections, though this is somewhat uncommon.
Phytophthora belongs to the class Oomycetes, which also includes Pythium and downy mildew. The pathogen is spread by splashing water where zoospores swim to infect roots, foliage and stems. Oospores produced are the resting/survival equipment of the pathogen; they’re responsible for the random reoccurrences under certain conditions. Sanitation is the link that breaks the chain of the reinfection process.
Control options
Management of both aerial pathogens, Rhizoctonia web blight and aerial Phytophthora, includes practices to reduce humidity within the canopies of susceptible crops. Allow for adequate spacing and facilitate good air flow. Avoid late-day irrigation and saturated conditions that leave wet foliage going into the night. Both fungi are soil-borne and rely on movement through splashing and running water to spread.While some fungicides may control both pathogens, it’s important to note that products for Phytophthora must be carefully chosen and rotated, due to reported resistance to mefenoxam (Subdue) among some Phytophthora species. To reduce further resistance, rotation with other MOA products will improve performance. For foliar aerial Rhizoctonia and aerial Phytophthora, foliar sprays are recommended. While the tables below are provided as a summary, growers must read and follow the entire pesticide label. Products other than those mentioned may be safe, legal and effective. Not all products may registered for use in all states. Contact GGSPro as needed for further guidance.
Aerial Rhizoctonia web blight control options
Product Name | MOA | Size | Comments | Item Number |
---|---|---|---|---|
Affirm | 71-1129 | |||
Broadform | 71-1290 | |||
Banner Maxx II | 71-2972 | |||
Cease | 71-13301 | |||
Chipco 26019 Flo | 71-1350 | |||
Chipco N/G | 71-13501 | |||
Cleary’s 3336 EG | 71-2550 | |||
Cleary’s 3336 -F | 71-2575 | |||
Companion | 71-1375 | |||
Concert II | 71-1365 | |||
Daconil Ultrex | 71-1420 | |||
Daconil Weather-stik | 3117025 | |||
Fame SC | 71-1505 | |||
Heritage | 71-1400 | |||
Medallion WDG | 71-16502 | |||
Mural WG | 71-1690 | |||
OHP 6672 4.5 L | 71-2670 | |||
OHP 6672 50 WSP | 71-2672 | |||
Orkestra Intrinsic | 71-2200 | |||
Pageant Intrinsic WG | 71-26801 | |||
Palladium WDG | 71-2685 | |||
Protect DF | 71-2745 | |||
Spirato GHN | 71-2948 | |||
Terraguard SC | 71-3018 | |||
Triathlon BA | 71-3040 |
Aerial Phytophthora control options
Product Name | MOA | Size | Comments | Item Number |
---|---|---|---|---|
Adorn | 71-1130 | |||
Aliette WDG | 71-11352 | |||
Alude | 71-27601 | |||
Areca | 71-1180 | |||
Broadform | 71-1290 | |||
Fenstop | 71-14801 | |||
Fosphite | 71-1520 | |||
Micora | 71-1655 | |||
Orvego | 71-2300 | |||
Pageant Intrinsic | 71-26801 | |||
Segovis | 71-3100 | |||
Segway O | 71-31101 | |||
Stature SC | 71-14652 | |||
Subdue Maxx | 71-2979 |
The Nightmare Before Christmas: How to Stop Pest and Disease Carryover
Fall crops have wrapped up across the country. If they haven’t already, growers will soon say, “Goodbye and good riddance!” to the problems of last season. Hopefully – unless the problem was a pest or pathogen with the potential to overwinter. Whether you’re a continuous or seasonal grower, don’t let your nightmare before Christmas come back to bite on St. Patrick’s Day or Easter.Recurring disease nightmares
Thielaviopsis, Fusarium and Sclerotinia are some of the most insidious diseases, due to their ability to carry over, at some level, from season to season, year to year. Each has a mechanism that allows spores to survive through even harsh environmental conditions.![]() |
Sclerotinia sclerotiorum on lettuce |
True sanitation is accomplished only by a two-step process:
- Chemical cleaning to remove major contaminating particles and films
- Disinfection with a sanitizer to eliminate remaining organisms and their spores
For the first step, we recommend Horti-Klor or Strip-It Pro. For the second step, Kleengrow or one of the oxidizing sanitizers (ZeroTol 2.0 or SaniDate 12.0) must be used to effectively eliminate disease spores. Contact GGSPro for detailed cleaning and sanitation protocols, usage rates and disease-specific information.
Recurring pest nightmares
Insects that can overwinter include thrips, mites and mealybugs, all of which can survive the winter in your facility, heated or not! Aphids, which normally bear live young, lay eggs to overwinter. However, this is generally not recognized as a greenhouse issue. Read on to see how other persistent pests survive to haunt you.Thrips nymph or larval stages mature until they drop down from the foliage to pupate in the potting soil or soil-based floor. This is the overwintering stage. The pre-pupa and pupa stages of thrips don’t feed, so they’re immune to pesticides that work through ingestion. The pupal stages are also tolerant to most other pesticides used to control thrips.
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Thrips in helianthus |
If you’ve been fighting a major thrips infestation in a crop, plan to clean up immediately after the space empties. Pull all weeds: They can be loaded with thrips, eggs to adults. Clean up all plant debris and sweep, blow or wash the floors.
If thrips populations have been high, consider the further step of drenching a soil-based floor to eliminate carryover due to the pupae. Bio-insecticides Ancora or Botanigard WP, or the beneficial nematode Steinernema feltiae can be used to break the life cycle.
Mites survive the winters in a resting state, called diapause, in the cracks and crevices of soil or concrete floors of unheated greenhouses. Once the mites have gone into hiding, not much can be done to control them. Knocking them down in the crops before they go into diapause is ideal.
Start by removing any weeds and plant debris, and treat with an effective miticide or biological control during the crop cycle. Make sure the floors are weed-free when closing the house down. During diapause, the two-spotted spider mites turn red. They emerge from their hiding places in spring to summer, sporting the red color.
As temperatures warm up, thoroughly scout problem areas of the prior season. If mites are detected, treat with a miticide or battle them with predatory mites Phytoseiulus persimilis, Neoseiulus fallacis or Amblyseius andersoni. P. persimilis is required for biological control once webbing is seen. N. fallacis and A. andersoni won’t penetrate webs, so they must be used earlier in the life cycle. However, fallacis and andersoni are active at temperatures down into the 40s, making them amenable to late fall applications. Furthermore, fallacis can establish and overwinter in a cold greenhouse. If you’re new to biological controls, check with GGSPro regarding prior chemical usage.
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Mealybugs congregate on chrysanthemum |
Battle mealybugs in your crops with spray applications of Altus, Aria or Rycar, or MOA 4A products such as Flagship, Safari or Tristar. For a soft chemical approach, use Suffoil-X to suffocate the pests. Suffoil-X can be used with an added insect growth regulator such as Distance IGR or Talus 70DF as a second mode of action.
For a biological approach, before the heat is turned down, use Ancora or Botanigard WP; mix with Azatin O for its insect growth regulator effect. Keep in mind, all of these products will require contact to have any effect on overwintering mealybugs. Scout previously infested areas frequently in the coming season for any re-appearance and treat immediately if seen.
Of course, always read and follow all label instructions. Rotate products with at least three different modes of action to prevent development of pesticide resistance. Products other than those mentioned here may also be safe and effective.
Product | MOA | Item Number | |
---|---|---|---|
Cleaners | |||
Horti-Klor | 74-2105 | ||
Strip-It Pro | 74-2125 | ||
Sanitizers | |||
Kleengrow | 74-21151 | ||
SaniDate 12.0 | 71-35351 | ||
ZeroTol 2.0 | 71-35501 | ||
Biological Insecticides | |||
Ancora | 70-1166 | ||
Azatin O | 70-12301 | ||
Botanigard WP | 70-12521 | ||
Chemical Insecticides | |||
Altus | 70-1161 | ||
Aria WDG | 70-3399 | ||
Flagship 25 WG | 70-1700 | ||
Rycar | 70-2900 | ||
Safari 20SG | 70-29951 | ||
TriStar 8.5SL | 70-85221 | ||
Insect Growth Regulators | |||
Distance IGR | 70-1465 | ||
Talus 70 DF | 70-1172 | ||
Biological Control Agents | |||
Amblyseius andersoni | broad and cyclamen mites | packaging options | |
Neoseiulus fallacis | |||
Phytoseiulus persimilis | will penetrate webbing | ||
Steinernema feltiae | fungus gnats and shoreflies |
Tech Tip Articles
-
March 2021
Phytophthora Root Rot and Aerial Blight Management
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February 2021
Bring Down the Intensity this Spring with Shade
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January 2021
An Aphid BCA Guide for Dummies
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December 2020
Preventing Disease In Propagation
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November 2020
The Relationship Between Water Quality and Fertilizer Programs
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October 2020
Poinsettias - Tips for End of Season Success
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August 2020
Heat Stress in Plants
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June 2020
Fall Pansies - Fighting Black Root Rot and Phytophthora
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April 2020
Insect Pest Control Roulette
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April 2020
Extending Shelf Life and Marketability of Spring Plants
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March 2020
The ABCs of BCAs
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January 2020
Plant Lighting – Introduction into Supplemental and Sole-Source Lighting
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December 2019
Plant Lighting - Introduction into Photoperiodic Lighting
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October 2019
New Products from the Softer Side of Pest Control
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September 2019
Algae Is A Slippery Slope
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August 2019
Cyclamen Production - Plan Now to Succeed
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July 2019
Garden Mum Disease, Insect, and Mite Control Options
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June 2019
Defense Against Fusarium Wilt in Chrysanthemum
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May 2019
Beautiful Disaster: How to Defend Against Spotted Lanternfly
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April 2019
Good to the Last Raindrop: How to Protect Crops Through Prolonged Wet Weather
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March 2019
Into the Great Wide Open: Tips to Transition Spring Crops from Greenhouse to Outdoors
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February 2019
Geraniums: A Crop Culture Tune-Up
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January 2019
A Greenhouse Game Changer: Introducing the Bluelab 3-in-1 Pulse Meter
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December 2018
Blinded by the Blight: What to Do When Your Foliar Disease is Actually a Soil-Borne Pathogen
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November 2018
The Nightmare Before Christmas: How to Stop Pest and Disease Carryover