• Field Performance of Admire Against Silverleaf Whitefly on Commercial Iceberg Lettuce, 1993-1998

      Palumbo, John C.; Byrne, David N.; Baciewicz, Patti (College of Agriculture, University of Arizona (Tucson, AZ), 1999-10)
      Whitefly populations in the Yuma area have been reduced to levels that growers can cost-effectively manage. Data from our studies suggest that these declines in pest populations are largely attributed to the use of Admire 2F (imidacloprid) soil treatments. Relative to the outbreaks in 1993-1994, whitefly populations during the past four growing seasons have remained at sub-economic levels on lettuce crops throughout the growing areas in Yuma This chemical has provided excellent control of whiteflies on fall lettuce, and aphids on spring lettuce. After 6 years of evaluation in commercial fields, the product appears to remain highly efficacious, maintaining good residual activity. Studies in 1998 on fall broccoli and melons crops further support this conclusion. Factors responsible for this sustained efficacy of Admire are discussed.
    • A Practical Approach for Managing Lepidopterous Larvae with in Head Lettuce

      Palumbo, John C.; Byrne, David N.; Baciewicz, Patti (College of Agriculture, University of Arizona (Tucson, AZ), 1999-10)
      During the past 5 years, the efficacy and field performance of several new insecticides for control of Lepidopterous insects on desert lettuce crops has been investigated in small plot trials at the Yuma Agricultural Center and in produce fields with commercial cooperators. The objective has been to determine how these new chemistries will fit into pest management programs in Arizona. Thus, research programs have been focused on studies to define use patterns for these insecticides chemicals that can be integrated into our local management programs in the most cost-effective way possible. This report was created to provide an overview of the new chemistries being developed, their field activity and characteristics, and guidelines for use in head lettuce. In addition, an approach for sustaining the long-term efficacy of these products is discussed.
    • Preliminary Examination of the Population Dynamics and Control of the Lettuce Aphid on Romaine

      Palumbo, John C.; Byrne, David N.; Baciewicz, Patti (College of Agriculture, University of Arizona (Tucson, AZ), 1999-10)
      Several small plot studies were conducted during the spring of 1999 to examine the population growth, distribution and control of the lettuce aphid on romaine. The lettuce aphid population developed to greater numbers more quickly and spread among plants more rapidly when compared with other aphids species under late spring growing conditions. Most of the lettuce aphids sampled were found on the hearts of the plants rather than the frame and wrapper leaves. Our preliminary efficacy studies suggest that foliar sprays, when timed properly and with proper coverage, can provide adequate control of the lettuce aphid for up to 14 days. Furthermore, significant suppression of apterous lettuce aphid populations was observed in plots where pyrethoid treatment were sprayed for thrips control. The implications of these results for future research and management of lettuce aphids in desert lettuce is discussed.
    • Residual Efficacy of New Insecticide Chemistries Against Cabbage Looper in Head Lettuce

      Palumbo, John C.; Byrne, David N.; Baciewicz, Patti (College of Agriculture, University of Arizona (Tucson, AZ), 1999-10)
      Several new insecticide chemistries were evaluated and compared with standard chemistries for residual efficacy against cabbage looper in lettuce. Four field trials were conducted at thinning, and heading stages of lettuce. These replicated trials clearly demonstrate that the new insecticides provide a solid 7 day residual efficacy (>90% control) following spray applications. Overall, Success at rates ranging from 4.5-6.0 oz/acre appeared to provide the most consistent residual activity on larvae present on plants at time of application. Confirm, appeared to have less consistent residual, but control was generally similar to Success. The newer compounds Proclaim and Avaunt, showed good residual efficacy for up to 7 days, and will be a welcome additions to the growers insecticide arsenal. Finally, the fact that all of these compounds are effective against large larvae, in part explains their consistent residual activity on lettuce.