Page 15 - Griffin Gazette Issue 2 - 2022

AVELYO FROM BASF
The active ingredient is from mode of action (MOA) group 3. This means it shares the MOA with popular
fungicides such as Eagle and Terraguard. While it is not recommended to rotate within the MOA 3 group, BASF
says that the unique chemistry of Avelyo makes it less likely that a disease resistant to other MOA 3 fungicides
would also be resistant to Avelyo. Like other MOA 3 fungicides, Avelyo is a broad-spectrum fungicide that is
particularly effective against rust and powdery mildew diseases. It has a 12 hr REI and has shown excellent plant
safety on many ornamentals. Avelyo can also be drenched for Cylindrocladium and Thielaviopsis root diseases.
GGSPro is available to help growers create sound rotations for disease, insect and mite control.
POSTIVA FROM SYNGENTA
Postiva is a broad-spectrum fungicide/bactericide representing MOA groups 3 & 7. Since there are multiple
fungicides that contain one or the other of those MOAs, rotations will be also important with Postiva. In addition
to greenhouse and nursery grown ornamentals, Postiva is labeled for certain vegetable transplants for retail
sales. Foliar sprays are effective against: Botrytis, powdery mildew, rust and Rhizoctonia. Interestingly, Postiva
is also labeled to suppress bacterial leaf spots caused by Pseudomonas and Xanthomonas, when applied as a
foliar spray or drench. Other diseases controlled by a drench of Postiva include Fusarium and Rhizoctonia. Foliar
sprays have a 12 hr REI and drenches have a 0 hr REI if there will be no contact with treated surfaces.

SEIDO FROM OHP
Seido is a powdery mildew specialist product with a brand-new mode of action for horticulture, MOA 50.
Powdery mildew resistance to some commonly used fungicides is occurring, making this new MOA welcome
news for ornamental growers in greenhouse and nursery production. Seido is best used as a preventative
treatment that takes advantage of translaminar and leaf vapor activity to enhance coverage. It can be tank mixed
with most other foliar applied fungicides for broad spectrum activity. Seido has a 4 hr REI.

Fall Asters and Garden Mums have their fair share of foliar disease issues. These new fungicide introductions
will improve the options available for prevention and treatment. Both of these fall favorites are susceptible to rust
infections. Garden mums can host brown rust, and the notorious Chrysanthemum White Rust (CWR). Avelyo and
Postiva are very effective against rust. Since both contain a MOA 3 active ingredient, they should not be rotated
with each other, or with other MOA 3 fungicides such as Eagle. Since Eagle is considered to be curative by the
USDA in their CWR eradication protocol, GGSPro recommends using these 2 products early in the crop, so other
modes of action can be used before utilizing Eagle (or other products containing myclobutanil) if CWR is detected
in a crop.

Powdery mildew is a common problem on fall asters and preventative treatments are recommended. Garden
mums can host powdery mildew, but we seldom see it in outdoor production. All 3 of the new fungicides are very
effective against powdery mildew. Seido with its unique MOA would be a great choice for garden asters since
they are frequently treated for powdery mildew with MOA 3 fungicides.
Pseudomonas cichorii is a bacterial leaf spot that often effects garden mums in summer seasons with repeated
rain events and for those produced with overhead irrigation. Postiva, applied as a foliar spray or drench is
reported to suppress Pseudomonas leaf spot. Postiva also controls the fungal diseases Botrytis and aerial
Rhizoctonia, that are also encouraged by frequent leaf wetting events.

GGSPro encourages sound fungicide rotation strategies to maximize efficacy and reduce resistance pressure.
There are many other effective fungicides beyond the 3 that are highlighted in this article. The pesticide label is
the law, and it is the grower’s responsibility to read and follow all label requirements.

Aster Powdery Mildew and Rust Chrysanthemum Brown Rust Chrysanthemum White Rust