• Evaluation of Admire Soil Treatments on Colonization of Green Peach Aphid and Marketability of Lettuce

      Palumbo, John; Kerns, David; Hannan, Todd; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1995-08)
      Admire (imidacloprid), applied as a soil treatment, protected lettuce plants from developing infestations of green peach aphid, Myzus persicae (Sulzer), for 60-100 d after planting based on two small plot and two commercial field trials. Admire applied 7.6 cm sub-seed furrow provided longer and more consistent protection from green peach aphid than treatments applied to the soil surface, as a side-dress, or 15.2 cm sub-seed furrow. Surface band applications of Admire provided inconsistent control probably because of inadequate hydrological incorporation into the soil. In small plot trials, effective control of aphids by Admire applied 7.6 cm sub seed furrow resulted in greater than 90.0% marketable heads while the untreated plots contained 20.0% marketable heads. When used in a commercial setting, Admire applied 7.6 cm sub-seed furrow on leaf lettuce prevented aphid colonization (<3 aphids per plant) for approximately 100 d after planting, while the untreated and commercial standard treated areas contained 30.7 and 26.8 aphids per plant respectively at 100 d after planting. In addition, marketability of lettuce was greater in Admire treated plots. As a sub-seed furrow treatment, Admire provides a more suitable approach to aphid control than is currently available with foliar insecticides.
    • Relative Susceptibility of Red and Gree Color Morphs of the Green Peach Aphid to Foliar and Systemic Insecticides

      Kerns, David L.; Palumbo, John C.; Byrne, David N.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1995-08)
      Foliar and systemic insecticide bioassay techniques were developed for testing insecticide susceptibility to two color morphs of the green peach aphid. Six foliar and one systemic insecticide were used in our evaluations. These insecticides included three organophosphates, two pyrethroids, one organochlorine, and one chloronicotinyl. One of the green colored populations tested was collected from spinach, and red and green color populations were collected from the within the same cabbage field. The red morph was found to be less susceptiblethan the green morphs to Dimethoate, Karate, and Endosulfan. Their were only slight differences in susceptibility to the foliar insecticide between the green morphs. The greenmorph from spinach was found to be the most susceptible to Admire, while the two morphs collected from cabbage did not differ. Leveling off of aphid mortality at about 85% with high doses of Admire may indicate highly tolerant types in the populations, or an artifact of the methodology.
    • Relative Susceptibility of Red and Green Color Forms of Green Peach Aphid to Insecticides

      Kerns, D. L.; Palumbo, J. C.; Byrne, D. N.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1999-02)
      Field populations of green peach aphid, Myzus persicae (Sulzer), were collected from five produce fields near Yuma, Arizona. Three of the fields sampled contained both red and green-colored forms, while the remaining two fields contained only green-colored green peach aphids. Red-colored aphids were consistently more resistant to dimethoate and lambda-cyhalothrin, and usually more resistant to endosulfan than green-colored aphids collected from the same field. Slight differences in susceptibility to imidacloprid suggest that development of resistance is a possibility and justifies close resistance monitoring. Susceptibility to imidacloprid was not influenced by color form. We detected little or no differences in susceptibility to acephate, mevinphos or bifenthrin.