Control of Sweetpotato Whitefly in Cantaloupe with Various Pesticides, 1992

Cantaloupes ‘Topmark’ were direct seeded on 20 Feb into single row “yuma beds” on 203 cm centers and thinned to 30 cm intervals at the University of Arizona, Yuma Valley Agricultural Center. Plots consisted of 4 beds, 18 m long with a 3.6 m buffer between plots. Plot preparation and seasonal maintenance followed local practices. Two applications of the fungicide Myclobutanil were made on 14 May and 20 May to suppress powdery mildew. Plots were arranged in a randomized complete block design with 4 replicates. Applications were made with a 4-row high-pressure, electrostatic boom sprayer equipped with stainless steel, hollow-cone nozzles (TX-18) spaced at 50 cm and delivered 563 liter/ha at 320 psi. Applications were initiated when immature whitefly densities reached measurable levels. A total of 5 applications were made on 23, 29 Apr, and 8, 13, and 20 May. The pH of the application water was 7.1. Addition of the Aliette to the water caused the pH of the mixture to decrease to 3.5 pH. A spreader/sticker was not used. Insect data were collected only from the inner two beds of each plot. Plots were sampled on 22, 24 and 30 Apr, and 9, 14, and 21 May. Adult SPWF were assessed by randomly selecting 20 leaves from the terminal area on primary vines (4th fully expanded leaf from the apex of the vine) in each plot. The underside of each leaf were carefully turned upward and the number of live adults on the surface was recorded. Counts were made at sunrise between 0500-0600 hrs. Data were analyzed for treatment differences using ANOVA and Ryan’s Q test. Bartlett’s test estimated a heterogeneity of variance and treatment means were log transformed prior to analysis of variance.