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How to Manage Pests

UC Pest Management Guidelines

Adult false chinch bug, Nysius raphanus.


False Chinch Bug

Scientific name: Nysius raphanus

(Reviewed 1/07, updated 8/08)

In this Guideline:


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, bugs move to feed on virtually any nearby green plants, including irrigated fruit and nut trees, grains, and vegetable crops.


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 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 abundant, consider treating weedy borders to kill bugs before they migrate.

Common name Amount to use R.E.I.+ P.H.I.+
(trade name)   (hours) (days)

  Calculate impact of pesticide on air quality
When choosing a pesticide, consider information relating to the impact on natural enemies and honey bees and environmental impact.
4–9 pt/acre
  COMMENTS: Apply as a foliar spray. Use of this material will disrupt biological control of other pests such as scales, thrips, mites, and whiteflies.
+ Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
1 Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode of action Group numbers are assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.



[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Avocado
UC ANR Publication 3436
B. A. Faber, UC Cooperative Extension, Santa Barbara/Ventura counties
J. G. Morse, Entomology, UC Riverside
M. S. Hoddle, 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

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