• Sweetpotato Whitefly (Bemisia Tabaci Gennadius) Population Relationships to Cotton Yield and Quality

      Chu, C. C.; Henneberry, T. J.; Akey, D. H.; Prabhaker, N.; Perkins, H. H.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Sweetpotato whitefly (SPWF) Bemisia tabaci Gennadius strain B has been a devastating pest of cotton in Arizona and California in recent years. Management systems involving cultural procedures, SPWF population monitoring crop sanitation, crop sequencing chemical control and other technology are developing slowly. SPWF population information in relation to cotton yield and quality losses are urgently needed Preliminary studies with cotton insecticide treatments initiated each week from shortly after cotton seedling emergence to late in the cotton season were conducted at the Irrigated Desert Research Station, Brawley, CA in 1993. The results suggest significant correlations for numbers of SPWF per leaf disc from cotton leaves vs. cotton yield and lint stickiness. Cotton lint yield was negatively correlated to all stages of SPWF populations (-0.783 or higher). Lint stickiness was high positively correlated to SPWF populations (0.707 or higher) and cotton defoliation was positively correlated to SPWF populations (0.876 or higher).
    • Whole Season Rotational Pesticide System for Integrated Pest Management for Control of Sweetpotato Whitefly in Cotton

      Akey, D. H.; Henneberry, T. J.; Wuertz, D. A.; Silvertooth, Jeff; USDA, ARS, Western Cotton Res. Lab., Phoenix, 85040; Sundance Farms, Coolidge, AZ 85228 (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      A season long pesticide rotational system for cotton management of Bemisia tabaci (Gennadius) (SPWF) was put in place. The system tried to minimize pesticide impact on midseason build -up of beneficials against SPWF. SPWF thresholds were used to begin use of "potent, efficient" insecticides to stop exponential increase of SPWF in late season. Insecticide class rotation was a key element of the system to prevent insecticide resistance. Comparisons between test blocks and best agricultural practices for rest of field showed that SPWF eggs and large immature of September populations, yields (2.68 bales /Ac), and beneficials were about the same among the blocks. The cotton was free of stickiness in the entire field.