How to Catch a Fly

The pepper maggot is a sporadic pest; not appearing at all on a given farm or infesting up to one hundred percent of the pepper fruit. Farmers often respond to such threats by applying regular cover sprays whether or not any pest is actually present in their field. Cover sprays eliminate beneficial insects which control secondary pests, such as aphids, and often result in more pesticide applications. The key to eliminating many of these unnecessary sprays is to know when and where pepper maggot flies are present.

After attempting to capture the fly with over two dozen different types of trap/bait combinations, in many different positions around the field, we finally succeeded. The most successful monitoring system uses a rectangular, yellow, sticky-trap baited with liquid ammonia, hung 20 feet high, in the canopy of sugar maple trees next to pepper fields.

It was not easy to come up with this system! The flies do not respond to traps placed in the crop, even though they obviously deposit eggs in the fruit nearby. In the period from 1996 to 1998 we attempted to trap flies at varying heights in the canopy of several common species of trees that exist along the borders of Connecticut pepper fields. We found that the flies respond much better to traps placed at a mid-canopy height (about 20 feet) than to lower positions. We also captured up to 14 times more flies in sugar maple trees than in other species.

In 1998, UConn’s IPM Program demonstrated to eight Connecticut vegetable farmers how to save 18,530 pounds of pesticide active ingredient (worth $33,667) from being applied to 221 acres of peppers. These growers saved an additional $117,700 by reducing pest damage to their peppers.

By: Jude Boucher, University of Connecticut, Vegetable IPM Coordinator, Reviewed 2012.

Originally published: IPM Report to the Legislature. 1998.

This information was developed for conditions in the Northeast. Use in other geographical areas may be inappropriate.

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