Lately, I have received numerous calls about how to control grasshoppers and crickets around homes and gardens. And currently, my office has been invaded by crickets, the common field crickets not the Mormon Crickets. So, the question is, "What can I do about these critters?"
According to Jeff Knight, state entomologist, Nevada Department of Agriculture, "Grasshoppers come from wet weather, crickets from droughts. As pests go, grasshoppers are worse...they eat everything."
Grasshoppers and crickets are closely related insects that belong to the Order Orthoptera. Nearly 400 grasshopper species inhabit the 17 Western States, but only a small percentage is considered pest species.
Grasshoppers can be the most noticeable and damaging insects to yards and fields. They also are among those most difficult to control, since they are highly mobile. For many reasons, grasshopper populations fluctuate greatly from year to year, and may cause serious damage during periodic outbreaks. Problems tend to increase beginning in early summer and can persist until hard frosts.
The most important factors affecting their populations are weather related, particularly around the time of egg hatch. For example, cold, wet weather is very destructive to newly hatched grasshoppers. However, very dry winter and spring conditions also can be harmful to survival since required tender new plant growth is not available.
Grasshoppers will readily feed on garden and landscape plants. Among vegetable crops certain plants are favored, such as lettuce, carrots, beans, sweet corn, and onions. Squash, peas, and tomatoes (leaves, not fruit) are among the plants that tend to be avoided. Grasshoppers less commonly feed on leaves of trees and shrubs. However, during outbreak years even these may be damaged. Furthermore, grasshoppers may incidentally damage shelterbelt plantings when they rest on twigs and gnaw on bark, sometimes causing small branches to die back.
During periods when a local outbreak develops, control usually involves using sprays or baits. To be successful these need to be applied to developing stages of grasshoppers and concentrated at sites where egg laying occurs. Ability to control grasshoppers declines as grasshoppers develop and migrate.
Treatments should be directed at the young grasshoppers and nearby vegetation present in these breeding sites. Insecticide options are greater for larger acreages and unit costs are less expensive. The addition of canola oil to insecticide sprays can improve control by making treated foliage more attractive to feeding grasshoppers.
Alternately, baits containing carbaryl (Sevin) can be broadcast. Bait formulations are made by mixing the insecticide with bran or some other carrier and kill grasshoppers that feed on the bait. These treatments limit application effects on other insects present in the treated area. However, availability of Sevin baits is frequently limited, or prohibitively priced for use on large areas. Baits must be reapplied after rain. Insecticide treatments do not need to completely cover the area since grasshoppers are mobile. Insecticides applied as bands covering 50 percent of the area, or even less, have proved very effective for control of grasshoppers in rangelands. Backpack sprayers and application equipment modified for use on ATVs can be used in larger acreages. A review of this method, known as Reduced Area Acreage Treatments (RAATS) has been prepared by the University of Wyoming at: www.sdvc.uwyo.edu/grasshopper/atvraats.htm .
Where grasshoppers develop over large areas and impact several properties, coordinated area-wide control is very useful. As this requires some additional preparations in planning, early surveys are even more important. Grasshopper control often is much more successful as a community effort.
Once grasshoppers have reached the adult stage and migrations occur, some insecticides may be applied directly to plants. Such applications have only short effectiveness and damage can occur before individual grasshoppers are killed. Furthermore, the choice of insecticides is more limited since few allow direct application to garden fruit and vegetables.
Federal land management agencies, State agriculture departments, county and local governments, private groups, and/or individuals can request assistance from the U.S. Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS) to suppress rangeland grasshopper populations. Under the Plant Protection Act (PPA), APHIS has the authority, subject to funding availability, to treat Federal, State, or private lands that have economic damage.
Closing note, it is rumored that crickets can tell the outside temperature: Count the number of
chirps they make in one minute, divide by 4 and then add the number 40 to reach the outside temperature.
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