University of Maryland Extension

Grasshoppers: Life Cycle and Control

Stanton Gill, Extension Specialist, University of Maryland Extension
Grasshopper on zinnia

Life Cycle

In early September the weather has changed to hot and dry, at least for this week. Many weeds are drying up and grasshoppers are moving into container grown perennials and annuals. Some growers are reporting feeding damage on their plants in garden centers, nurseries and greenhouse operations growing plants outdoors. Grasshoppers cause some damage every year, but they become very destructive during dry periods. The main factor affecting grasshopper populations is weather. Fortunately, we have had a fairly wet summer and the populations of grasshoppers are not as high as the last couple of summers. Outbreaks, or exceptionally large populations, are usually preceded by several years of hot, dry summers and warm autumns. Dry weather increases the survival of nymphs and adults. Warm autumns allow grasshoppers more time to feed and lay eggs. The thing of concern with grasshoppers is that they have a high reproductive capacity. The female lays an average of 200 - 400 eggs per season. Female grasshoppers deposit their eggs below the soil surface in pod-like structures. Each egg pod consists of 20 to 120 elongated eggs cemented together. Egg pods are very resistant to moisture and cold and easily survive the winter if the soil is not disturbed. Grasshoppers deposit eggs in fallow fields, ditches, fencerows, and weedy areas. Fortunately, only one generation of grasshoppers is produced in most years.

Grasshopper on zinnia flower
Grasshopper on zinnia flower
Grasshopper damage on dahlia flower
Grasshopper damage on dahlia flower

Eggs hatch was late this year and occurred mainly in June and July. Many of the egg hatched late because the spring was cool and wet. Nymphs go through five or six developmental stages and become adults in 40 to 60 days, depending on weather and food supply. In September, you will find mainly adults feeding.

Control Options

Biological Control Options: The good news is that grasshoppers have many natural enemies that help control their populations. A fungus, Entomophthora grylli, kills many grasshoppers when the weather is warm and humid as it was in the summer of 2013. Infected grasshoppers grasps onto  plants in a death embrace with the front and middle legs, while the hind legs are extended. They die in this position. Fungal spores develop in and on the grasshopper’s body, then become airborne and infect other grasshoppers. This is a natural occurring fungus and cannot be purchased in the marketplace. Another natural enemy is a protozoan, Nosema locustae. This product can be purchased and applied near nursery growing areas. Its spores have been incorporated with bran to make insecticide baits such as Semaspore®, Nolo Bait® or Grasshopper Attack® (These are a couple I found available on the Web and there may be others available). These baits kill some nymphs but almost no adults, though infected adults lay fewer eggs. Baits act too slowly and kill too few grasshoppers to be useful for immediate control. This method obviously would have be applied back in mid-summer and is not practical for the adults that are present in September.

Mechanical Control: One way to control grasshopper populations is to eliminate sites where they might deposit eggs. Grasshoppers prefer undisturbed areas for egg laying, so tilling weedy areas in  late summer discourages females. If you have weedy areas near your growing plots trying rototilling the area in September.

Controlling summer weeds by cutting them down or applying herbicides in fallow areas during the summer leaves very little food sources for nymphs to feed on when eggs hatch. Eliminate tall grass and weeds from around any plants you wish to protect to make the area less attractive to grasshoppers and make it easier for birds to prey on grasshoppers.

Chemical Control: Finally, insecticides can be applied to the foliage of your nursery and greenhouse plants to control the adults. Acephate or permethrin will provide about 7 to 10 days of control. Only choose this option if feeding is significant.

Grasshoppers are active in September, but the damage should be down this fall unless it becomes hot and dry.

September 2013
The information given herein is supplied with the understanding that no discrimination is intended and no endorsement by University of Maryland Extension is implied.   

Maintained by the IET Department of the College of Agriculture and Natural Resources. © 2021. Web Accessibility

University programs, activities, and facilities are available to all without regard to race, color, sex, gender identity or expression, sexual orientation, marital status, age, national origin, political affiliation, physical or mental disability, religion, protected veteran status, genetic information, personal appearance, or any other legally protected class. If you need a reasonable accommodation to participate in any event or activity, please contact your local University of Maryland Extension Office.