How to Manage Pests

UC Pest Management Guidelines

Tomato

False Chinch Bug

Scientific name: Nysius raphanus

(Reviewed 12/13, updated 12/13, pesticides updated 9/16)

In this Guideline:


Description of the Pest

The adult false chinch bug is a small bug, about 0.12- to 0.16-inch (3–4 mm) long. It is gray to light brown in color and looks somewhat like a small lygus bug. The false chinch bug nymph is gray with a reddish brown abdomen.

False chinch bugs can occur in high numbers on weeds adjacent to, or within, tomato fields. The eggs are laid randomly on the soil or within soil cracks near weeds. The false chinch bug spends the winter primarily in the immature stage (nymph) on weeds, especially mustards. As weeds dry in spring or are destroyed, false chinch bugs may begin mass migration through tomato fields, where they feed. Nymphs predominate during migration, but adults also may be present. Important weeds that serve as hosts include wild mustard, wild radish, shepherd's-purse, and London rocket. Mustard crops, such as canola, can also be important sources of false chinch bug migration. The most serious infestations result from spring migrations; however, fall migrations can also occur. Insect movement occurs in early morning or evening when temperatures are cool, but bugs can be seen throughout the day. False chinch bug populations are likely to build to high levels during years with high winter rainfall.

Damage

False chinch bugs can be an occasionally serious problem on fresh market tomato fruits. Their feeding causes indiscernible lesions on green fruits, which later become apparent as numerous, small black spots when fruits are treated with ethylene to bring on ripeness and color. Feeding on tomato foliage can cause leaves to turn brown and drop. Seedlings or newly transplanted tomatoes can be killed by the high number of migrating bugs more commonly occurring along the field edge.

Management

Outbreaks of false chinch bugs are unpredictable from year to year and for various geographic locations. Monitor adjacent areas and prevent populations from migrating into tomato fields, if possible.

Cultural Control

Some control can be achieved by flaming or cultivating adjoining weedy areas, grasslands, or pastures. Frequent cultivation of infested areas may inhibit migrating populations.

Organically Acceptable Methods

Cultural controls are acceptable for use on an organically certified crop.

Monitoring and Treatment Decisions

If large numbers of false chinch bugs are present in fields, treatment may be warranted. Insecticide treatment of tomato field borders may be effective in limiting invasion of migrating false chinch bugs. Treat either in the evening or early morning when chinch bugs are active.

Common name Amount per acre REI‡ PHI‡
(Example trade name)   (hours) (days)

UPDATED: 9/16
Calculate impact of pesticide on air quality
Bee precaution pesticide ratings
The following materials are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Not all registered pesticides are listed. Always read the label of the product being used.
 
A. PERMETHRIN*
  (Pounce 25WP) 3.2–12.8 oz 12 0
  (Ambush 25W) 3.2–12.8 oz 12 0
  MODE-OF-ACTION GROUP NUMBER1: 3A
  COMMENTS: Do not apply to cherry tomatoes or other varieties that produce fruit less than one inch in diameter. Do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
 
B. BETA-CYFLUTHRIN*
  (Baythroid XL) 2.8 fl oz 12 0
  MODE-OF-ACTION GROUP NUMBER1: 3A
  COMMENTS: Apply to soil in a minimum of 10 gallons water/acre next to or below the transplants with standard preplant fertilizer equipment just before transplants are set out in field. A maximum of one pre-transplant application is allowed per crop season.
 
C. FENPROPATHRIN*
  (Danitol 2.4EC) 10.66 fl oz 24 3
  MODE-OF-ACTION GROUP NUMBER1: 3A
 
D. ESFENVALERATE*
  (Asana XL) 9.6 fl oz 12 1
  MODE-OF-ACTION GROUP NUMBER1: 3A
  COMMENTS: Do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
 
E. ZETA-CYPERMETHRIN*
  (Mustang) 2.4–4.3 fl oz 12 1
  MODE-OF-ACTION GROUP NUMBER1: 3A
  COMMENTS: Do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
 
Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) is the number of days from treatment until harvest can take place. In some cases the REI exceeds the PHI. The longer of these two intervals is the minimum time that must elapse before harvest may take place.
* Permit required from county agricultural commissioner for purchase or use.
# Acceptable for use on organically grown produce.
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-actiongroup numbers are assigned by IRAC (Insecticide Resistance Action Committee).

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Tomato
UC ANR Publication 3470

Insects and Mites

E. T. Natwick, UC Cooperative Extension, Imperial County
C. S. Stoddard, UC Cooperative Extension, Merced and Madera counties
F. G. Zalom, Entomology, UC Davis
J. T. Trumble, Entomology, UC Riverside
G. Miyao, UC Cooperative Extension, Solano and Yolo counties
J. J. Stapleton, UC IPM Program and Kearney Agricultural Center, Parlier (false chinch bug)
Acknowledgments for contributions to Insects and Mites:
C. G. Summers, Entomology, UC Davis and Kearney Agricultural Center, Parlier
C. F. Fouche, UC Cooperative Extension, San Joaquin County
N. C. Toscano, Entomology, UC Riverside

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