How to Manage Pests
UC Pest Management Guidelines
Scientific Name: Leptoglossus zonatus
(Reviewed 2/17, updated 2/17, corrected 1/19)
In this Guideline:
Description of the pest
The leaffooted bug gets its name from the small spined leaflike enlargements found on the hind legs of large nymphs and adults. Adult bugs are about 1 inch long and have a narrow brown body with a yellow or white zigzag line across their flattened back and two yellow spots on the pronotum, the platelike structure just behind the head.
Leaffooted bugs have two to three generations per year and prefer to feed on seeds of crops like almond in the spring, pistachio in the summer, and pomegranate in the fall. In the late fall leaffooted bugs seek out protected areas, such as citrus trees or the spaces between palm fronds, to overwinter as adults in aggregations. They remain in these aggregations until the following spring and disperse into other crops from late March through May.
The leaffooted bug is an occasional pest of citrus in the San Joaquin Valley and usually only occurs in groves that are adjacent to preferred summer and fall hosts like pistachio and pomegranate. Leaffooted bugs can cause damage to mature citrus fruit in the winter and early spring, and to young fruit if the bugs are still present after bloom.
Leaffooted bugs feed by inserting their large proboscis (mouthparts) into fruits and nuts in search of seeds. In citrus, where seeds are typically lacking, bugs probe through the rind multiple times and feed on juice. On large fruit, probing does not cause any visible external damage on the rind, but can cause significant damage internally when juice sacs are punctured and desiccate. On small fruit, the area around the penetration site becomes slightly sunken and discolored as the fruit expands over time.
Treatment thresholds for this pest have not been developed for any crop, including citrus. Citrus growers in the lower San Joaquin Valley that are near nut crops or pomegranate orchards should monitor groves for overwintering aggregations of adults between November and March.
In the unlikely event that aggregations are still found in the orchard in April and May, and small fruit are present, an insecticide application may be warranted.
The only insecticides known to have long-term efficacy on leaffooted bugs are pyrethroids and organophosphates. However, use these products cautiously (e.g. spot treat or use rates that minimize harm to natural enemies), as they have broad-spectrum effects on natural enemies and pollinators.
There are no cultural controls available for leaffooted bug. The only biological control is an egg parasitoid, Gyron spp., that is unable to attack the adult stage of leaffooted bug that is present during the winter in citrus.
UC IPM Pest Management Guidelines:
Insects, Mites, and Snails
E. E. Grafton-Cardwell, Lindcove Research and Extension Center, Exeter and Entomology, UC Riverside
Acknowledgments for contributions to Insect, Mite, and Snails:J. Barcinas, E.S.I., Corona, CA
R. Dunn, Badger Farming Co., Exeter, CA
J. Gorden, Pest Management Associates, Exeter, CA
C. E. Kallsen, UC Cooperative Extension, Kern County
D. Machlitt, Consulting Entomology Services, Moorpark, CA
C. Musgrove, retired entomologist, Riverside, CA
K. Olsen, S & J Ranch, Pinedale, CA
N. V. O'Connell, UC Cooperative Extension, Tulare County
P. A. Phillips, UC IPM Program, UC Cooperative Extension, Ventura County
T. Roberts, E.S.I., Corona, CA
T. Shea, UC Cooperative Extension, Riverside County
J. Stewart, Pest Management Associates, Exeter, CA
P. Washburn, Washburn & Sons Citrus Pest Control, Riverside, CA