Grasshopper: Friend or Foe?

Its summer and the summertime pests are out in force. Grasshoppers are on my hit list this week. We came back from a July 4th celebration and found the grasshoppers had left the pastures and moved to our landscape. Their presence will continue to grow as the pastures dry out. Consecutive years of hot, dry summers and warm, dry autumns favor grasshopper survival and reproduction. Warm, dry fall weather allows grasshoppers more time to feed and lay eggs. Large numbers of grasshoppers in the late summer can deposit large numbers of eggs which hatch in the spring.

I hope this recent wet weather will help control some of the grasshoppers.  Wet weather encourages growth of a fungus, Entomophthora grylli, which often causes high mortality. Infected grasshoppers strike a characteristic pose at the top of a plant or other object. The grasshopper grasps the plant in a death embrace with front and middle legs while the hind legs are extended. It dies in this position.  Fungal spores develop in and on the body of the infected grasshopper. These spores become airborne and infect other grasshoppers. Under warm, humid conditions, great numbers of grasshoppers have been destroyed by this fungus.

During hot, dry summers, weedy hosts dry up and grasshoppers fly in search of green plants. The search for food can result in large numbers of grasshoppers concentrating in orchards, crops and irrigated landscapes.

Grasshoppers are susceptible to many insecticides. However, insecticides typically do not persist more than a few days and grasshoppers may soon re-invade the treated area. The length of control will depend on the residual activity of the insecticides and the frequency of retreatment. Controlling grasshoppers over a large area will reducethe numbers present which can re-infest a treated area. Dimilin 2L provides long residual of young hoppers but is not effective against adults.

A few years ago when we had a bad grass hopper infestation and the hoppers were continually trying to crawl up the fruit and shade trees to feed in the canopy I started spraying the trunks of the trees every 5 or so days.  The results were outstanding as you see the grass hoppers rarely fly in to a tree to feed. The hoppers usually crawl into the trees & shrubs to feed.

Some insecticides for controlling grasshoppers in the home landscape include: Cyfluthrin, the active ingredient in Bayer Advanced Home and Garden Spray and Tempo; Bifenthrin, the active ingredient in Ortho Ready-to-Use Houseplant and Garden Insect Killer; Permethrin, the active ingredient in Spectracide and other products; and Acephate, the active ingredient in Orthene. Note: Tempo (cyfluthrin) and Demon (cypermethrin) are labeled for use by Professional Pest Control Operators for insect control in lawns and landscapes. It is important that you remember to read and follow all label directions.

If you need further information contact the Bosque County Extension Office.

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