This summer is shaping up to be a bad one, again, as far as grasshopper infestations are concerned in the East Texas area. Producers seeing these insects in their hay fields should determine if their infestation is heavy enough to warrant treatment and, if treatment is necessary, should utilize a chemical that fits their production scheme.
Texas is home to around 150 different species of grasshoppers; however, only about 5 of these species cause damage to pastures, lawns, gardens, trees, and shrubs.
Outbreaks of these insects are usually preceded by several hot, dry summers and falls, which enable more of their eggs to survive in the ground over winter and also allows for a longer egg laying season.
Grasshopper eggs begin to hatch in late April, with peak hatch occurring around mid-June into July for most of the pest species. Only one generation experienced a year and adult grasshoppers begin laying eggs around late July and on into the fall.
Young grasshoppers are referred to as 'nymphs' and look like adults, except that they have wing pads instead of wings. Nymphs go through 5 to 6 stages (called instars) during the 40 to 60 days it takes to become adults.
Control products for grasshoppers include formulations of Sevin, Malathion, and Dimilin. Sevin and Malathion are contact killers. Sevin has a maximum number of ounces that you can spray per acre per year and also has a withdrawal period between spraying and grazing the pasture or cutting it for hay of 14 days. Dimilin is a Restricted Use produce that is labeled for pastures and must be used before the third instar (nymphal stage). Dimilin is not effective on adult grasshoppers.
In general, finding more than 7 grasshoppers per square yard in a field would indicate that it is economically justifiable to spray. Expect to pay somewhere between $6 and $9 per acre for insecticides used to treat these pests.
For more information on grasshoppers, you might want to visit the following links:
http://insects.tamu.edu/extension/bulletins/l-5201.html or http://citybugs.tamu.edu/FastSheets/Ent-1043.html
The information given herein is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by Texas Cooperative Extension is implied.
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