
An Environmentally Friendly
Pesticide Curtails Cotton PestsBy Linda McGraw May 4, 2000Two of cottons worst enemies are
conceding to an environmentally friendly insecticide called spinosad. Approved
for use on more than 100 crops--including apples, almonds, citrus, eggplant,
tomatoes, cotton, and coffee--spinosad is poised to replace malathion, until
now the most widely used insecticide against the Mediterranean fruit fly. Agricultural Research Servicescientists in College Station, Texas, have years of expertise developing new
tactics to test this new insecticide on commercially-grown cotton. Cotton
bollworms and budworms have developed resistance to most commonly used
commercial insecticides. As a result, these insects now infest over 75 percent
of the U.S. cotton crop. Aerial applications of spinosad were applied with a small droplet size (200
micron) and a 5-gallon spray rate. Commercial cotton treated at this level had
fewer damaging bollworm and budworm larvae compared to cotton treated with
other pesticides. Larvae found on cotton treated with standard insecticides
were more mature, suggesting that spinosad prevented small larvae from becoming
larger and more damaging. Typically, spray rates for standard insecticides
average about 2 to 3 gallons per acre. The Texas study was conducted through a trust fund cooperative agreement
between ARS and the makers of spinosad, Dow
AgroSciences LLC, of Indianapolis, Ind. Just as important, these studies
established that spinosad is nontoxic to beneficial insects like lady beetles
and pirate bugs. More beneficial insects were found on cotton treated with
spinosad, but fewer of them survived on cotton treated with standard
insecticides. ARS is the chief research agency for the U.S.
Department of Agriculture. Scientific contact: Ivan W. Kirk, Areawide Pest Management Research Unit, College Station, Texas, phone (979) 260-9584, fax (979) 260-9386, [email protected]. U.S. Department of Agriculture | |