Grasshoppers can be one of the most damaging pest in Texas. 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. 30 mature grasshoppers per yard can eat up to 1 ton of vegetation in 10 days, the same as 1 mature cow. They are capable of eating ˝ their weight each day.
These insects cause some damage every year, but become very destructive during outbreak periods. An often asked question during outbreak years is: Why are there so many? Weather is the main factor affecting grasshopper populations. Outbreaks are usually preceded by several years of hot, dry summers and warm autumns. While last year wasn’t a warm autumn we have had two hot dry summers in 2009 and 2008. Dry weather increases nymph and adult survival, much like we are experiencing this year. Warm autumns allow grasshoppers more time to feed and lay eggs. Cool, wet weather slows nymphal development, reduces the number of eggs laid, and increases the incidence of diseases.
Grasshoppers have a high reproductive capacity. Grasshoppers lay their eggs in the fall about ˝ to 2 inches below the soil surface in pods. Pods can include 40 – 4000 eggs, with an average of 200 eggs during a single season. 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. Not all eggs are laid and hatched at the same 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.
I can’t tell you whether or not it would be economical to spray for grasshoppers in pasture or rangeland conditions, that is for you to decide. Can you buy a bale of hay cheaper than spraying? In homeowner and garden situations they are much easier to control. I will tell you this, if you are spraying your 50 acre coastal hay field and your surrounded by native pasture land or your neighbor isn’t spraying his you will be unsatisfied because grasshoppers are always on the move and the neighbors will soon be on your place.
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.
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 is a form of biological control that can be used on grasshoppers. It is a 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. Products include Sevin (Carbaryl 4F), Malathion, Mustang Max and Dimilin. Dimilin must be used when grasshoppers are young and in the nymph stage as it is a IGR (insect growth regulator). Mustang Max may be your best option this time of year and has no grazing or hay restrictions. Sevin has a 10 day grazing and haying restriction.
Homeowners options include using chemicals that include active ingredients such as bifenthrin, permethrin or cyfluthrin or insecticides such as Diazinon, Malathion or Sevin. Always read label instructions for specific crop uses, preharvest intervals and other precautions.
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. Although it is getting late for this year, and optimal or economical control may not be obtained, 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 grasshopper control in pasture or homeowner situations please feel free to contact the Texas AgriLife Extension office in Somervell County at 254-897-2809.
References to trade names or commercial products is made with the understanding that no discrimination is intended and no endorsements by the Texas AgriLife Extension Service is implied.
Somervell County Texas Agrilife Extension Office
P.O. Box 895
1405 Texas Dr.
Glen Rose, TX 76043
Educational programs of the Texas AgriLife Extension Service are open to all people without regard to race, color, sex, disability, religion, age, or national origin.
The Texas A&M University System, U.S. Department of Agriculture, and the County Commissioners Courts of Texas Cooperating
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