(Neuroptera : Chrysopidae) Adult lacewings are highly mobile and inhabit and reproduce in wheat. Lacewings that inhabit wheat are predaceous only as larvae. Adults feed on aphid honeydew, nectar, and pollen. Lacewing larvae feed on a variety of small, soft-bodied arthropods, including aphids, plant bugs, thrips, mites, and the eggs and larvae of Lepidoptera and Diptera. Lacewings are not considered to be highly effective at controlling aphids because they lack the prey specificity usually associated with highly effective aphid predators. However, they contribute to controlling aphid infestations.
(Coleoptera : Coccinellade) Lady beetles occur in wheat fields throughout the United States. They prey primarily on aphids (including the greenbug) but may also eat spider mites, other insect larvae and insect and mite eggs. Because of the wide climatic and geographic conditions under which wheat is grown, and the complexity of predator-prey relationships, general statements about coccinellid impact on aphid infestations are difficult to make. Under favorable conditions coccinellids are voracious predators and can drive an aphid infestation to extinction.
(Hemiptera : Nabidae) Nabids (damsel bugs) feed on small, soft-bodied arthropods in wheat fields. Both adults and immatures are predaceous. Nabids are widely distributed in wheat and other crops, and are frequently among the most abundant predatory insects in wheat fields. Adult nabids are winged and highly mobile. Nabids are not considered highly effective at controlling aphids because they lack the prey specificity associated with highly effective aphid predators. However, they contribute to the control of aphid infestations.
(Hymenoptera : Aphidiidae) The parasitic wasp Lysiphlebus is the most important biocontrol agent of the greenbug in wheat. Mummies produced by Lysiphlebus from the aphid it killed are either tan or brown depending on which species of aphid it parasitized. Tan mummies are formed from greenbugs while brown mummies are formed from bird cherry-oat aphids. This parasitoid can be effective at maintaining greenbug infestations below economically damaging levels. Researchers at OSU and USDA-ARS have recently determined thresholds for parasitism that lead to successful control of greenbug infestations in wheat fields in Oklahoma.
Photo courtesy of: David Cappaert, Bugwood.org