STP1146: Ovicide Formulation and Aerial Application Parameters Influence Control of Tobacco Budworm on Cotton

    Kirk, IW
    Agricultural engineer, entomologist, and agricultural engineer, Aerial Application Research Unit, Southern Crops Research Laboratory, Agricultural Research ServiceTexas A&M University, College Station, TX

    House, VS
    Agricultural engineer, entomologist, and agricultural engineer, Aerial Application Research Unit, Southern Crops Research Laboratory, Agricultural Research ServiceTexas A&M University, College Station, TX

    Bouse, LF
    Agricultural engineer, entomologist, and agricultural engineer, Aerial Application Research Unit, Southern Crops Research Laboratory, Agricultural Research ServiceTexas A&M University, College Station, TX

    Pages: 21    Published: Jan 1993


    Abstract

    Amitraz, profenofos, and thiodicarb at active ingredient rates of 0.14, and 0.28 kg/ha were aerially sprayed onto field-grown cotton plots containing separately-grown potted cotton plants in 1990 and 1991. The potted plants were artificially infested with laboratory-reared Heliothis virescens eggs prior to spraying and 1 and 2 days after spraying. Spray rates of 18.7 and 46.8 L/ha were used. Two droplet sizes, small and large (average Dv0.5 = 202 and 306 μm, respectively) were used for each spray rate and ovicide combination. An aircraft speed of 145 km/h with nozzles oriented back was used for large droplets and 209 km/h with nozzles oriented down for small droplets. Both egg and larval mortality were increased by increasing active ingredient rates, but the responses to increased active ingredient rates were different for the different ovicides. The responses of egg and larval mortality to changes in spray mixture rate and droplet size were also different for the different ovicides. Larval mortality was higher than egg mortality for all of the ovicides. Both ovicide (and/or its formulation) and aerial application variables influenced the spray droplet deposition parameters: droplet size, droplet density, and percent coverage as measured on water sensitive paper. Results of these studies indicate that both formulators and applicators can increase efficacy of ovicides by modifying formulations and adjusting application parameters for each ovicide.

    Keywords:

    Aerial application, cotton, ovicide, insecticide, application rate, spray rate, droplet size, nozzle orientation, Heliothis, egg mortality, larval mortality, fruit damage


    Paper ID: STP20203S

    Committee/Subcommittee: E35.22

    DOI: 10.1520/STP20203S


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