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Origin and Distribution
The bagrada or painted bug, Bagrada hilaris (Burmeister), is a recently introduced pest of cole crops and weeds in the western United States. Native to Africa, it has also spread to India, Pakistan, Sri Lanka, the Middle East and Italy. In the U.S. it was first found in Los Angeles County, California in 2008, Bagrada bug now occurs in California, Arizona, New Mexico, Utah, and Texas.
The bagrada bug is a plant-feeding stink bug, primarily attacking cole crops in the family Brassicaceae. It feeds on weeds, flowering plants, and cultivated mustards such as arugula, Asian greens, India mustards, broccoli, brussels sprouts, cabbage, cauliflower, canola, radish, sweet alyssum and turnip. When populations are high and preferred host plants are scarce bagrada bugs can be found on a variety of other plant species (sometimes causing damage).
Potential Impact and Spread
The presence of brassicaceous weeds is thought to have contributed to the range expansion of bagrada bug. In the southwestern U.S., mustard weeds grow in the winter, providing bugs with ample food at times when crops approach harvest and become tough and less desirable. As temperatures increase, bug density can rapidly increase. Weeds along highways and irrigation canals provide corridors into agricultural areas. The late summer planting of commercial mustard and cole crops serve as hosts for bugs that survive the summer. Since these crops are just sprouting at the end of summer, feeding by the insects quickly destroys the plants.
Life Cycle and Identification
Adult males and females are similar in appearance, measuring 5–7 mm, with the female being larger. The back of both sexes is black with orange and white spots, and the underside of the abdomen can vary from black to dark cream. Adults are commonly found copulating and positioned end-to-end. The bagrada bug overwinters in the adult stage and lays eggs in the spring through early fall. The eggs, unlike other stink bugs, are laid individually or in small groups. Eggs are laid on the undersides of leaves, hairy stems of plants, and in cracks in the soil. New eggs are slightly barrel-shaped and dirty white, gradually becoming orange-red as the embryo develops. Upon hatching, nymphs are reddish. The legs, head and thorax gradually darken within hours of hatching and the nymphs resemble small adult lady beetles. There are 5 nymphal stages. Later instars exhibit elaborate markings, and the 5th instar shows white markings on the thorax and abdomen along with the presence of wingpads. Aggregations containing both nymphs and adults become increasingly common as densities increase, generations overlap, and food sources decrease.
Multiple generations per year exist in the warm desert areas. The generation time is 2–3 weeks during the summer months. Bagrada bugs have their highest survival rates at temperatures between 75°F and 91°F. Higher or lower temperatures increase development time and cause increased mortality.
Damage (Plant Symptoms)
The bagrada bug inserts its needle-like mouthparts into plant tissues, injects digestive enzymes and sucks the juices. Bagrada bug feeding initially results in a starburst-shaped lesion. Continued feeding can cause leaf death and kill seedlings. Bagrada bugs feed primarily on leaves, flowers and young seed pods. In head-forming crops, feeding damage results in no heads being formed or multiple small heads. Bagrada bugs aggregate together which increases the damage in the places they are aggregated within a field.
Monitoring for bagrada bugs in the morning after temperatures are above 85°F can determine if a field is infested. Leaves with starshaped lesions may be easier to spot than the insects themselves. In young cole crop fields, bugs may be found at the plant/soil interface during early morning and late afternoon when temperatures are cooler. Removing weedy mustard plants from around fields can reduce the number of bagrada bugs in area between cole crops.
Contact your local Extension Agent for insecticide recommendations.
For information about the Pest Alert program, please contact Laura Iles, co-director of the North Central IPM Center, at firstname.lastname@example.org. This publication was produced and distributed by USDA-NIFA Regional IPM Centers and the 1862 Land-Grant Universities.
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Thomas M. Perring and Darcy A. Reed, Department of Entomology, University of California, Riverside, CA 92521
John C. Palumbo, Department of Entomology–Yuma Agricultural Center, University of Arizona, Yuma, AZ 85364
Tessa Grasswitz, Department of Entomology, Plant Pathology and Weed Science, Extension Plant Sciences, New Mexico State University, Los Lunas, NM 87031
C. Scott Bundy, Department of Entomology, Plant Pathology and Weed Science, New Mexico State University, Las Cruces, NM 88003
Walker Jones USDA-ARS, Biological Control Unit, Stoneville, MS 38776
Monica Papes, Department of Zoology, Oklahoma State University, Stillwater, OK 74078
Tom Royer, Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078
This work is supported by the Crop Protection and Pest Management Program (2018-70006-28884) from the USDA National Institute of Food and Agriculture.