How to Manage Pests
UC Pest Management Guidelines
False Chinch Bug
Scientific name: Nysius raphanus
(Reviewed 9/16, updated 9/16)
In this Guideline:
DESCRIPTION OF THE PEST
The false chinch bug (family Lygaeidae) adult is mostly light to dark gray, elongate, and about 0.12 inch (3 mm) long. Females lay eggs on host plants or in cracks in soil. The mostly pale gray nymphs have inconspicuous reddish to brown abdominal markings. There are from four to seven generations per year. All stages can be present throughout the year.
During winter and early spring, false chinch bug primarily feeds on foliage, stems, and seeds of wild grasses and cruciferous weeds. When vegetation dries or is cut, or weeds are treated with a herbicide, bugs move in large numbers to feed on virtually any nearby green plants, including irrigated fruit and nut trees, grains, and vegetable crops. These feeding aggregations can be very large.
False chinch bug occasionally causes severe injury on young trees by sucking sap from shoots and young stems. Infested shoots wither and die suddenly after attack, which typically occurs in May and June. Economic damage normally occurs in groves away from the coast only on young trees in border rows adjacent to uncultivated areas or grasslands. Otherwise healthy mature trees tolerate bug feeding.
Monitor during late winter and early spring if young avocado trees are growing inland near unmanaged areas most susceptible to false chinch bug migrations. Before winter weeds dry or are cut, look for bugs on fences and weedy areas adjacent to young trees.
If false chinch bugs are common, consider treating weedy borders to kill bugs before they migrate. Only border trees may need treatment.
UC IPM Pest Management Guidelines: Avocado
J. G. Morse, Entomology, UC Riverside
Acknowledgment for contributions to Invertebrates:P. A. Phillips, UC IPM Program, UC Cooperative Extension, Ventura County
M. Blua, Entomology, UC Riverside
P. Oevering, UC Cooperative Extension, Ventura County
D. Machlitt, Consulting Entomology Services, Moorpark, CA
T. Roberts, Integrated Consulting Entomology, Ventura, CA
B. B. Westerdahl, Nematology, UC Davis