ABSTRACT
Curacron, Larvin, and Ovasyn at rates of 0.125, and 0.250 lb(AI)/acre were aerially sprayed onto potted cotton plants placed in field-grown cotton. The potted plants were artificially infested with laboratory-reared Heliothis virescens (Fab.) eggs prior to spraying and 1 and 2 days after spraying. Spray rates of 2 and 5 gal/acre were used.Two droplet sizes, small and large (average Dv.5 210 and 330 pm) were used for each spray rate and ovicide combination. An aircraft speed of 90 miles/h with nozzles oriented back was used for large droplets and 130 miles/h with nozzles oriented down for small droplets. Both egg and larval mortality were increased from 11 to 24 % and from 68 to 74 %, respectively, by increasing active ingredient rates from 0.125 to 0.250 lb(AI)/acre. Each ovicide responded differently to the increases in active ingredient rate. Changes in spray rate and droplet size did not give consistent changes in egg and larval mortality from the ovicides. Larval mortality, which averaged 72 %, was significantly higher than egg mortality, which averaged 19 %, for all of the ovicides. Both ovicide (and/or its formulation) and aerial application variables influenced droplet deposition parameters. It should be possible for both formulators and applicators to increase efficacy of ovicides by modifying formulations and adjusting application parameters for each ovicide.
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