When hot, dry weather arrives the grasshoppers always seem to appear. For several weeks now we have been battling grasshoppers in pastures, cropland and home landscapes. There are control options available to assist producers and land owners with managing these insects but they must be applied in a timely manner when grasshoppers are still in the nymph stage.
Grasshoppers thrive when we have consecutive years of hot, dry summers and warm, dry fall conditions. When we have a fall that is dry and warm this allows more time for grasshoppers to feed and lay more eggs increasing their numbers in the spring. If numbers of grasshoppers in the late summer increase that also adds to the mass of eggs laid.
There are fungal diseases that can assist in decreasing numbers of grasshopper but they require spring rains while the eggs are hatching and grass hoppers are young.
There are approximately 150 different species found but the majority of damage comes from 5 different species. They are the Differential grasshopper, Red-Legged grasshopper, Migratory grasshopper, Two-striped grasshopper and the Packard grasshopper. Usually major grasshopper outbreaks will involve more than one species of grasshopper. They are capable of eating ˝ their weight each day.
Grasshoppers lay their eggs in the fall about ˝ to 2 inches below the soil surface in pods. Pods can include 20 – 120 eggs. These eggs pods seem to be very tolerant of weather conditions. The main areas to find these egg pods include the ditches, fencerows and roadways where there is little soil disturbance. Hay fields and weedy fields will also be an area where grasshoppers may lay their eggs. These eggs will hatch beginning in April with the peak hatch around the middle of June. Cool and dry springs may delay egg lay and let it carry into July. Higher temperatures will accelerate egg development, nymphal growth and adult female egg production. Grasshoppers only have one generation per year but not all of the eggs are laid and hatched at the same time which results in finding grasshoppers of all different growth stages at one time. Once the eggs hatch the grasshoppers are referred to as nymphs. This is the best time to control them. They will look very similar to adult grasshoppers but have wing pads instead of wings. There are 5 different nymph stages (known as instars) before a grasshopper reaches full maturity and begins reproducing.
Grasshoppers prefer rangeland and pastures. They look for vegetation with an open canopy and numerous patches of bare ground or reduced plant density. However when plant growth begins to dry up they will concentrate in areas looking for green plants.
There are three types of control methods for grasshoppers. They include cultural control, biological control and chemical control. Cultural control includes increasing the live plant basal cover, decreasing open areas and reduced grazing if possible. In cropland you can eliminate weedy areas by tillage, herbicides, sod –forming grasses or mowing. You can also delay planting if possible to avoid the heavy infestations of grasshoppers.
All of the cultural options are difficult, especially during dry and hot weather conditions. Cultural controls to protect young trees include vinyl tree protectors, tree wraps and tree trunk painting. Grasshoppers are usually not an issue on mature trees but can cause a great amount of damage to young or newly planted trees. In garden sites you can use floating row covers and place over plants that have heavy infestations. Controlling weeds can be very effective because it will starve out the young grasshoppers and discourage adults from laying eggs in that area due to the lack of food. When making management decisions it is always best to consider fallow fields or overgrown areas first. Areas with a lot of activity or soil disturbance are not ideal areas for grasshoppers to lay their eggs.
Biological control of grasshoppers includes their natural predators such as blister and ground beetles which attack the eggs. Other predators are birds, chickens and other fowl. Biological viruses and fungi found in nature can also help control or reduce the population but are usually not present in dry, hot conditions. Nolo Bait and Grasshopper Attack are a form of biological control that can be used on grasshoppers. It is an IGR or growth regulator that will stop the growth of the nymphs and eventually break the cycle. It does provide good control but must be used when the grasshoppers are small and will not control adults. It does take a while to see the results and is not an overnight fix.
Chemical control of grasshoppers can be used in non-crop land and improved pastures. Some active ingredients in products include carbaryl, zeta-cypermethrin, lambda cyhalothrin, and Dimilin. Dimilin must be used when grasshoppers are young and in the nymph stage.
Homeowner’s options include using chemicals that include active ingredients such as bifenthrin, permethrin, cyfluthrin, cyhalothrin, and carbaryl.
As with any pesticide, always read and follow the label directions. The label will tell you what crops the products can be used on, how much product can be applied, what insects can be controlled and harvest or grazing intervals.
To be effective against grasshoppers a plan must be in place before grasshoppers begin to appear in large numbers. It takes a plan utilizing the cultural, biological and chemical combination to be truly effective in controlling the pest. You can begin by checking for grasshoppers in the weedy areas and spot treat those areas as needed. In some years you will be able to stop an outbreak at that point.
For more information about this and other topic, contact the Texas A&M AgriLife Extension Office at (817) 556-6370. Zach Davis is a County Extension Agent with the Texas A&M AgriLife Extension Service in Johnson County specializing in agriculture and natural resources.
Extension programs serve people of all ages regardless of socioeconomic level, race, color, sex, religion, disability, or national origin. The Texas A&M University System, US Dept. of Agriculture, and County Commissioners Courts of Texas Cooperating. A member of The Texas A&M University System and its statewide Agriculture Program.