Many different insects attack leguminous vegetables. Aphids damage terminals, whiteflies feed on sap and transmit bean golden mosaic virus, and caterpillars, like bean leafroller, and beetles feed on leaves. Flower thrips feed in blossoms and stink bugs, corn earworm, and leaffooted bugs damage seeds and pods.
Snap beans are becoming an important crop for Florida. Southern peas (a bean) are typical in north Florida. Many other types of beans are grown on a small scale. Increas- ingly, newer pesticides are being registered for the entire crop group, including legumes such as pigeon pea, yardlong bean, sword bean, and crowder pea. Labels for individual insecticides should be consulted to see if they are labeled for all types of beans.
According to already published guidelines for snap beans (Pernezny et al. 2003), management practices should include scouting twice a week for insect pests in at least one location for every 2.5 acres. More sites should be chosen in small fields (less than 20 acres). A map of the field should be drawn so that pest counts can be connected to a particu- lar section of the field for future reference.
A sample is a 3 ft section of row. Whiteflies can be estimated by turning over several leaves in the section and counting the number of adults. Terminals should be examined for the presence of aphids. A three-by-three-foot cloth is placed on the ground for other pests, and the bean plants are shaken over it. Insects that fall on the cloth can be identified and counted. The growth stage of the plant and an estimate of defoliation should be recorded. Snap beans can tolerate up to 20% defoliation before pod set and 10% after pod set.
A systemic insecticide (a neonicotinoid) should be applied at planting to control aphids and whiteflies. Later in the season, when the effects of the systemic wear off, an insect growth regulator for whiteflies may be applied. Because it is the pod that is sold, damage to this part of the plant is the most serious concern. An insecticide appropriate for the pests present should be applied at pinpod. At least one more application may be needed before harvest.
For the organic grower, a number of OMRI-listed insecti- cides have been listed in the table (see the Notes column).
Pernezny, Ken, Gregg Nuessly, and William Stall. 2003. Integrated pest management for Florida snap beans. PPP37. Gainesville: University of Florida Institute of Food and Agricultural Sciences. 8 p. https://edis.ifas.ufl.edu/pp117.