Final Report for FS99-086
Tent caterpillars, army worms, horn worms, and grasshoppers were contributing, to varying degrees, to leaf defoliation in Frank’s pecan trees. He had used conventional applications of insecticides to eradicate these pests but he also ended up killing beneficial insects such as paper wasps, lady beetles and lacewings as well as harming beneficial bird populations.
He decided to colonize large numbers of Polistes wasps, commonly known as paper wasps, as a control against these pests. The paper wasp’s diet consists of soft-bodied insect pests such as caterpillars and some grasshoppers. The colonization of paper wasps in agriculture is not a new idea; Chinese farmers have used this technique since ancient times.
Since paper wasps can be permanently colonized, Frank built and placed 200 wasp boxes—which he built from PVC end caps and mounted on stakes about three feet high– throughout his twenty-four acre grove. He also later hung an additional 75 “boxes” from his trees. He had similar occupancy in the wasp boxes placed on stakes as hung in trees, 55 to 60 percent. But he noticed less bird predation of the wasps in the hanging wasp boxes than those on stakes.
An interesting complement to his insect control by wasps was that he also built bat boxes to provide homes to several thousand bats. These bat boxes were not a part of his producer grant but he used them to keep bats on his property because they eat insects. In fact, Frank is convinced that this combination of natural beneficial predators—wasps and bats–is more successful than one approach alone. His pest control system is also more diversified and less likely to fail him if something causes problems with a single predator; the other hungry predator already lives in his grove.