Evaluation of a Selective Insecticide for Control of Melon Aphid on Cantaloupe, 1997

Abstract

Abstract Two rates of CGA-215944 50 WP, one tested with as well as without the addition of a wetting agent, Kinetic (0.094%, vol:vol), were evaluated for effectiveness and residual activity and compared with a standard, broad-spectrum insecticide, Thiodan 3 EC. Cantaloupe was direct seeded on 2 Apr at the Central Florida Research and Education Center, Leesburg, FL. Each plot consisted of four 35-ft rows, 6 ft apart with plants spaced 2.5 ft apart. Treatments were replicated four times in a RCB design. On 25 Apr, all plants in all plots were infested with melon aphids that had been reared on squash under row covers to prevent predation and parasitism. All chemicals were applied with a 2-row tractor-mounted boom sprayer with 18 Albuz (lilac) ceramic hollow-cone nozzles, spaced 8 inches apart, delivering 133 gpa at 200 psi. Aphids were counted on 20 leaves of similar size per plot each week for 7 wk beginning on 13 May and ending on 24 Jun. Leaves were collected at least 5 DAT. Treatments were applied only when the grand mean of a treatment (the mean of the four replicate means) was equal to or greater than a treatment threshold of 5 aphids per leaf. Thus, all treatments were applied on 7 May, but on 21 May, only the higher rate of CGA-215944 was applied; on 28 May, only the lower rate without Kinetic; on 4 Jun, only the lower rate with Kinetic; and 18 Jun, only the higher rate. A square root transformation was used to stabilize the variance of counts for analysis. A two-way ANOVA and a mean separation test (Waller-Duncan k-ratio test) were used to determine significant differences among treatments.