A huge issue for southeastern growers is pests’ never-ending appetite for growing produce. Though there are several methods to manage pests, using beneficial insects as a natural technique can be effective. Ayanava Majumdar, Auburn University Extension entomologist, has been studying the use of beneficials to manage devastating pests in Alabama.
Lately, Majumdar has been testing beneficials in his trap-cropping system. He has been doing several experiments using sunflowers and sorghum as trap crops. Majumdar says he has seen several green lynx spiders. The spiders love the sorghum and sunflowers because they provide adequate shelter. He has seen the green lynx spiders feeding directly on adult leaffooted bugs and stink bugs. “It’s truly remarkable to see these beneficials in action,” he says.
Another beneficial insect Majumdar has seen in the trap crops is lady beetles. These beetles will move between the trap crop and the main crop, which is the goal of having beneficials in a production system. He says the reason the lady beetles will stick around the trap-cropping system is because it is a reduced-spray system, so there are not too many threats to their survival.
Majumdar is also experimenting with pest-exclusion systems. Pest-exclusion systems are great for keeping pests out of high tunnels. However, these systems can keep beneficial insects out of the tunnels as well. For example, using a 50 percent shade cloth can keep lady beetles and lacewings out of the high tunnels. However, growers can purchase beneficial insects to release in pest-exclusion systems. This means the grower can get even better control of small insects, like aphids, since they can still slip past the pest-exclusion system.
Majumdar adds that the two-spotted spider mite is a major pest in high tunnels. He has been doing several on-farm studies using persimilis mite to suppress the two-spotted sider mite, and it has been effective. “The persimilis mite suppresses the two-spotted spider mite,” Majumdar says.
Another insect that has been a major challenge for southeastern growers is the yellowmargined leaf beetle. According to Majumdar, researchers at the University of Florida have found that green lacewings can suppress yellowmargined leaf beetles. Green lacewings are a beneficial that can be purchased commercially. “They (green lacewings) can feed on up to 500 eggs or more, then 40 larvae of yellowmargined leaf beetle. So that’s some major destruction these beneficials can do,” Majumdar says.
Spine soldier bug also can suppress yellowmargined leaf beetle.
Majumdar says that beneficial insects play an important role in the ecosystem. Without them, major pest outbreaks may occur. So, it is important to conserve these beneficials by managing insecticides. According to Majumdar, beneficials can be killed off by basically any class of insecticides, including both organic and conventional formulations. Majumdar suggests managing sprays to conserve beneficial insects.
Majumdar recommends purchasing beneficials on a Monday or in the beginning of the week. If they are purchased on a Friday, the insects may sit in the mail over the weekend and can begin to die off.
“Always order them in the beginning of the week so they can arrive fresh at your door, ready to be released,” Majumdar advises. He says purchased beneficials can also be stored for a limited amount of time in containers so they can be released sequentially.
Hear Majumdar’s interview:
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