How to Manage Pests
UC Pest Management Guidelines
Several kinds of stink bugsfeed on cucurbits, but all are similar in life history and damage. Adult stink bugs are distinctly shield shaped, about 1/2 inch (1.3 cm) long and either brown or green. Some species have red, pink, or yellow markings. Eggs are laid in about fourteen to a cluster and are barrel-shaped with circular lids. Initially they are pearly white and later turn cream colored or pinkish just before hatching. For consperse stink bugs, a row of spines encircle the top of the eggs; the other species have concentric black rings on top of the eggs. Early nymphal stages resemble the adults in shape, but have various markings and patterns and no wings. Nymphs develop prominent wing pads as fourth and fifth instars.
The green stink bug is bright green with the entire lateral margin lined yellow, orange, or reddish. They are slightly larger (0.6–0.9 inch or 1.5–2.2 cm in length) and less common than the redshouldered stink bug which is predominantly green with a narrow red band across the shoulder, although sometimes the band is absent. Consperse stink bugs have gray brown to green bodies with yellow to orange legs and antennae with darkened tips. The body and legs are covered with small, black specks and the undersurface of the body varies from gray to green. Say's stink bugs have green and yellow colors on the head and back, are covered with tiny white flecks, have three pale spots at the base of the scutellum, and appear distinctly rounded when seen from above. These bugs develop in trees and weeds and move into green plants. Do not confuse these stink bugs with the rough stink bug, a predator that is speckled white and gray and is quite common in many crop areas throughout the year.
Feeding on immature fruit can cause growth distortion as well as irregular surface and internal spots on fruit at any time.
Stink bugs are sporadic and spotty seasonal pests. Adults overwinter on the ground under leaves, in orchards, legume crops, blackberries, or on certain weeds such as Russian thistle, mustards, and little mallow (cheeseweed). During mid- to late summer, populations can become quite high. These pests often move from undisturbed areas such as weedy fields and ditch banks as well as from riparian areas into crops. Monitor such adjacent areas to eliminate any surprise infestations. Check developing fruit for stink bugs. Time applications after the majority of eggs have hatched and nymphs are easily found. Individuals tend to hide by moving to the opposite side of the plant or fruit surface being observed.
|Common name||Amount per acre||REI‡||PHI‡|
|(Example trade name)||(hours)||(days)|
|The following 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.|
|MODE-OF-ACTION GROUP NUMBER1: 4A|
|COMMENTS: Foliar application.|
|(Warrior II with Zeon)*||1.28–1.92 fl oz||24||1|
|MODE-OF-ACTION GROUP NUMBER1: 3A|
|(Asana XL)||5.8–9.6 oz||12||3|
|MODE-OF-ACTION GROUP NUMBER1: 3A|
|COMMENTS: Repeat as necessary. Do not exceed 0.25 lb a.i./acre per season.|
|‡||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 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).|
|*||Permit required from county agricultural commissioner for purchase or use.|
UC IPM Pest Management Guidelines: Cucurbits
UC ANR Publication 3445
E. T. Natwick, UC Cooperative Extension, Imperial County
J. J. Stapleton, UC IPM Program, Kearney Agricultultural Center, Parlier
C. S. Stoddard, UC Cooperative Extension, Merced & Madera counties