Beneficial insects, also called biological control agents, are available to control a wide range of common greenhouse pests; aphids are one such menace. The predatory insects available to control aphids are voracious and highly mobile; specific strategies can even be used with these predators to help identify which types of aphids are present.
Predatory wasps are a group of related wasp species that prey on aphids. They are parasitoids, meaning the adult wasps are not feeding on the aphids. Instead, the wasps lay their eggs inside of live aphids. When the egg hatches, the larva lives and grows as an aphid parasite until it is ready to emerge as an adult wasp and seek out new prey. As the larva grows, it consumes the aphid from the inside out, leaving a hollowed-out shell called a “mummy”.
Bioline Agrosciences offers several parasitic wasp species to growers dealing with aphids. Aphiline, A. colemani, target small species, while Erviline, A. ervi, and Apheline, Aphelinus abdominalis, target larger species. When aphid species are able to be identified, growers should choose the appropriate species of predator. Unfortunately, identification is often difficult. In these cases, aphid predators can be purchased and released in mixes that can help both with covering a larger range of aphid species as well as identifying the general type of aphid.
When using predator mixes to combat unknown aphids, efficacy assessment relies on mummy scouting. Each of the aphid predators mentioned produces a mummy with slightly different appearances. A. colemani produce golden-brown mummies; A. ervi produce more golden-yellow-green mummies; finally, Aphelinus abdominalis produce totally black mummies. Aphid mummies can be found anywhere aphids are typically found – undersides of leaves and on stems is typical.
Once a grower identifies which aphid predator is having the most success through observing mummy appearance, single-species products can be selected if desired, and applications can continue until control is achieved. Growers should look for evidence that 75-80% of observable aphids have been parasitized to consider their outbreaks controlled. Future outbreaks can be prevented by continuing low-level, consistent releases. For information on application rates, release protocols, and product availability, contact your Griffin rep today!
