Grasshoppers are occasional insect invaders of yards and gardens in Arkansas and can be among the most difficult pests to control. For a variety of reasons, grasshopper populations cycle naturally from season to season and can cause extensive damage during outbreak years. Annually, grasshopper problems tend to increase as summer progresses but subside in Arkansas after the first frost.

Grasshoppers favor certain vegetable plants but tend to avoid other vegetables such as squash, peas and tomatoes (leaves, not fruit). They also usually avoid conifer trees and shrubs. However, during years when grasshoppers are extremely abundant and food is scarce, they feed on almost all plants.

Trees and shrubs, while not preferred feeding sites, may provide convenient resting places and grasshoppers often are found on them. They may nibble on foliage and tender bark, causing considerable injury over the course of a season. Established plants tolerate this leaf loss and usually recover and suffer little long-term injury. Grasshoppers breed and develop in dry, undisturbed sites such as pastures, empty lots and roadsides.

As plants in these areas dry out or are eaten, grasshoppers move to more lush growth found in yards and gardens. Successful management must include breeding areas. Grasshopper controls applied strictly to the yard will almost always achieve poor results because of problems with continuing reinvasion. Grasshoppers are most easily controlled with insecticides when they are still immature (nymphs) and their location is restricted to breeding areas.

After most grasshopper eggs have hatched (mid-June to early July), make a neighborhood survey to identify areas of developing grasshopper populations. Where high populations of grasshopper nymphs are detected (generally more than 10 per square yard), treat promptly to prevent later problems in adjacent areas. Options for grasshopper control in breeding areas include a number of insecticides formulated to be applied as either sprays or granules. Materials for grasshopper control are readily available through farm chemical distributors, farm coops, garden shops, hardware stores and similar retail outlets. Homeowner products for grasshopper control contain carbaryl or one of several pyrethroid insecticides (bifenthrin, cyfluthrin, gamma cyhalothrin, lambda cyhalothrin, deltamethrin, or permethrin) or pyrethrins for those wishing to use an organic insecticide. Over-the-counter products containing bifenthrin and lambda-cyhalothrin provide quick knockdown and long residual control, while products containing permethrin or cyfluthrin should also provide good control.

For more information, call the Van Buren County Extension office at 745-7117.