• Postemergence Herbicide Weed Control in Cole Crops Study

      Umeda, K.; Gal, G.; Murrieta, J.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1999-02)
      Weed control ratings at 3 weeks after treatment (WAT) showed that knotweed (Polvgonum argyrocoleon) and yellow sweetclover (Melilotus officinalis) were not controlled by oxyfluorfen (Goal®), pyridate (Lentagran®), clopyralid (Stinger®), sulfentrazone (FMC), or carfentrazone (FMC). Carfentrazone at 0.50 lb AI/A gave good control ( >89 %) of London rocket (Sisvmbrium irio) and sowthistle (Sonchus oleraceus). A lower rate at 0.125 lb AI/A provided acceptable control (85 %). Carfentrazone at 0.50 lb AUA caused severe broccoli and cabbage injury and crop stand reduction. Sulfentrazone at 0.50 lb AI/A gave nearly acceptable control of knotweed, London rocket, and sowthistle. Cabbage was severely injured and broccoli appeared to be more tolerant and injury was marginally acceptable (15 %). Stinger and Goal gave nearly acceptable control of sowthistle. Goal at 0.094 lb AI/A gave 80% control of London rocket. Goal caused marginally acceptable injury (12 to 17 %) and Stinger caused minimal crop injury. Goal appears to be ineffective against weeds at less than 0.094 lb AI/A and crop safety is very marginal. Lentagran was relatively safe on broccoli and cabbage but did not control the existing weed spectrum.
    • Evaluation of Insect Growth Regulators for Management of Whiteflies in Melons

      Palumbo, John C.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1999-02)
      Whitefly populations were assessed under different IGR exposure levels, and compared to Admire. When used alone during the season Applaud, Knack, and Sterling significantly reduced immature colonization similar to the standard Admire application and significantly greater than the untreated melons. Applaud treatments, regardless of spray frequency, showed the most consistent reduction in immature whiteflies. Applaud through its vapor activity also appeared to provide a long residual period of control against nymphs. Single applications of Knack and Sterling were considerably less effective in preventing colonization than applying these material twice during the season. These compounds appeared to have considerably less residual activity, which is consistent with their modes of activity. All of the IGRs had a significant impact on the distribution of nymphs among the leaves on the primary vine. In addition, Applaud provided the best melon quality. We now have a good understanding of how the IGRs influence whitefly population growth, the residual mortality of the IGRs and proper application timing for whitefly management. This information will allow us to develop a simple and reliable method that growers and PCAs can use to assess product performance and time spray applications.
    • Commercial Field Performance of Confirm and Success on Head Lettuce and Broccoli

      Palumbo, John C.; Hannan, Todd A.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1999-02)
      Field trials were conducted in the Yuma and Gila Valleys to assess the commercial field performance of Confirm and Success insecticides against beet armyworm and cabbage looper larvae. Ten lettuce and five broccoli fields were treated with combinations of Confirm, Success, and standard insecticides on various stages of plant growth. Success provided quick knockdown of larvae, but ultimately Confirm provided equitable control. Cabbage looper control with Confirm appeared to be influence by application volume and plant size. Addition of pyrethroid to Confirm did not provide additional efficacy. Success provided good suppression of leafminer adults and thrips. Both products provided control equal to conventional standards and will become valuable components of future lettuce pest management programs in Arizona.
    • Comparison of Alternative Management Approaches for Lepidopterous Larvae in Fall Lettuce

      Palumbo, John; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1999-02)
      For the second year, a large block experiment was conducted at the Yuma Ag Center to compare the field performance of three lettuce management programs for control of lepidopterous larvae. Conventional, experimental and biorational insecticides were sprayed to control beet armyworm, cabbage looper and Heliothis species throughout the growing season. Differences in populations of total larvae among the four treatments, relative to insecticide treatments and timing of application were observed throughout the season. In general, the standard and experimental treatments provided the most consistent control of lepidopterous larvae following each application. Harvest data showed that the spray regimes had a significant influence of head lettuce yield or quality. Maturity and quality were significantly reduced in the untreated control. An economic analysis shows that net returns varied widely among the management programs at different market prices. In conclusion, this study provides preliminary data to support the need for more development of experimental and biorational insecticide products as alternatives to conventional management programs in desert lettuce production.
    • Management of Aphids and Thrips on Leafy Vegetables

      Palumbo, John; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1999-02)
      Research has been conducted at the Yuma Agricultural Center for the past 5 years to gain an understanding of aphid and thrip population dynamics in spring lettuce, spinach and Cole crops. This information coupled with insecticide efficacy studies has allowed us to formulate recommendations for managing these serious pests of leafy vegetables. Provided below is information on species composition, sampling and chemical control of aphids and thrips. This paper should provide guidelines for pest control advisors and growers in making management decisions.
    • New Insecticide Alternatives for Aphid Management in Head Lettuce

      Palumbo, John; Mullis, Clayton Jr.; Reyes, Francisco; Amaya, Andreas; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1999-02)
      Several new insecticide was compared to Admire and Provado combinations for management of aphids in head lettuce in Yuma in two trials conducted in 1998. Foliar applications of Provado, Fulllfill, Aphistar and Acetamiprid appear to provide an alternative method of controlling aphids on lettuce comparable to prophylactic applications of Admire. In addition, at planting and side dress soil applications of thimethoxam provided aphid control comparable to Admire. The prevention of aphid colonization in lettuce heads with the foliar alternatives may depend greatly on the timing and frequency of applications before harvest occurs. Residual activity of the new foliar alternatives ranged from at least 7-14 days. These studies suggest that more than one application of the foliar products will be necessary to adequately suppress aphid contamination in heads. Evaluations of thiamethoxam suggest that it is more mobile in the soil than Admire and may be a candidate for side dress applications for aphid management.
    • Defining the Risk of Resistance to Imidacloprid in Arizona Whitefly

      Williams, Livy III.; Dennehy, Timothy J.; Palumbo, John C.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      A resistance management program for imidacloprid was initiated in Arizona in 1995, the ultimate goal of which is to sustain the efficacy of this insecticide against Bemisia. The current paper reviews our progress toward defining the risk of resistance to imidacloprid in Arizona whiteflies. Bioassay methods for adult whitefly consisted of a 1 day hydroponic uptake by cotton seedlings, followed by a 2 day exposure period. Results from statewide monitoring indicate that whitefly populations throughout Arizona are susceptible to imidacloprid; however, slight increases in resistant whiteflies were observed in 1996, as compared to 1995. Thus far, selection studies with various Arizona whitefly populations have not led to reduced susceptibility to imidacloprid. In a study exploring the influences of different cropping systems on imidacloprid use, we found no major differences in susceptibility to imidacloprid between populations of whiteflies in central and southwestern Arizona. Continued effective management of Arizona whitefly will, in part, hinge on our ability to more effectively integrate our knowledge of whitefly biology with resistance management strategies.
    • Seasonal Dynamics and Management of Whiteflies on Melons and Vegetables in the Desert Southwest

      Palumbo, John C.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      For the past 5 years, Arizona growers have been faced with the challenge of managing whiteflies populations to prevent yield reduction and loss of quality of their vegetable and melon crops. A large cooperative research effort was directed statewide to better understand how whiteflies develop on the numerous host -crops available and the environmental factors that influence their survival throughout the year. This information was used to develop short and long term management approaches for controlling whitefly populations. We quickly discovered that preventing whiteflies from colonizing plants was the key to successful management of whitefly populations in vegetable and melon crops. This report attempts to summarize what we presently understand about factors that influence the seasonal abundance of whiteflies in southern Arizona cropping systems. Non-chemical and chemical management approaches that have been developed by researchers and implemented by the agricultural communities are discussed
    • Temporal and Diagnostic Mortality of Cabbage Looper Larvae to Selective Insecticides in Head Lettuce

      Palumbo, John C.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      Several new insecticide chemistries were evaluated and compared with standard chemistries for temporal and diagnostic mortality of cabbage looper in lettuce. Three field bioassays of small and large larval mortality were conducted at pre-thinning, thinning, and postthinning, stages of lettuce. The compounds with translaminar activity (Alert, Success, and Proclaim) appear to be have the most rapid "knockdown activity" with 100% mortality consistently occurring by 1 -2 DAT. Because of their rapid activity, a large proportion of larvae are found dead on the plants. The products that need to be ingested to cause larval mortality (Larvin Confirm, Neemix, Crymax, Cryolite, MP 062) generally varied significantly in temporal mortality and in efficacy against larvae. Unlike the translaminar products, a large proportion of larvae on were often found missing from treated plants. The results of this study provide basic guidelines concerning the activity and assessment of the performance of these materials in the field PCAs and growers will ultimately be able to develop specific use patterns for these materials within their individual lettuce pest management programs.
    • Temporal and Diagnostic Mortality of Beet Armyworm Larvae to Selective Insecticides in Head Lettuce

      Palumbo, John C.; Kerns, David L.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      Several new insecticide chemistries were evaluated and compared with standard chemistries for temporal and diagnostic mortality of beet armyworm in lettuce. Field and lab bioassays of small and large armyworm mortality were conducted at pre- thinning thinning postthinning and harvest stages of lettuce. Results from both the field and laboratory indicated similar trends for the temporal activity of the products. The compounds with translaminar activity (Alert, Success, and Proclaim) appear to be have the most rapid "knockdown activity" with 100% mortality consistently occurring by 1-2 DAT. Because of their rapid activity, a large proportion of larvae are found dead on the plants. The products that need to be ingested to cause larval mortality (Larvin, Confirm, Neemix, Crymax, Cryolite, MP 062) generally varied significantly in temporal mortality and in efficacy against larvae. Unlike the translaminar products, a large proportion of larvae on were often found missing from treated plants The results of this study provide basic guidelines concerning the activity and assessment of the performance of these materials in the field PCAs and growers will ultimately be able to develop specific use patterns for these materials within their individual lettuce pest management programs.
    • Evaluation of Conventional and Experimental Insecticides for Control of Western Flower Thrips in Head Lettuce

      Palumbo, John; Mullis, Clayton Jr.; Reyes, Francisco; Amaya, Andreas; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      Studies were conducted in small plot field trials to evaluate the efficacy of several experimental and conventional insecticide chemistries against western flower thrips in head lettuce. Results from two trials using new experimental compounds showed that several insecticides have potential for management of thrips populations. All of the products appear to be good candidates for thrips control and had efficacy against adults and nymphs. Success and Fipronil consistently provided comparable control to the standard Lannate/Ammo. In the trial evaluating conventional compounds, Orthene/Mustang and Lannate/Ammo combinations provided the best control of both adult and nymphs. Plant size and temperature may be important factors contributing to the efficacy of these products.
    • Evaluation of Foliar Insecticide Approaches for Aphid Management in Head Lettuce

      Palumbo, John; Mullis, Clayton Jr.; Reyes, Francisco; Amaya, Andreas; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      Provado insecticide (imidacloprid) was compared to Admire and other standard insecticides for management of aphids in head lettuce in Yuma 1995 and 1996. Foliar applications of Provado appear to provide an alternative method of controlling aphids on lettuce comparable to prophylactic applications of Admire. The prevention of aphid colonization in lettuce heads with Provado may depend greatly on the timing and frequency of applications before harvest occurs. These studies and other studies on spinach suggest that more than one application of Provado will be necessary to adequately suppress aphid contamination in heads. The label suggests that applications be timed 5-7 apart. Our data tends to support this recommendation. Furthermore, timing applications should be based on days to harvest, level of aphid colonization and duration of aphid migration.
    • Management of Lepidopterous Larvae Under Experimental, Biorational and Conventional Control Programs in Lettuce

      Palumbo, John C.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      A large block experiment was conducted at the Yuma Ag Center to compare the field performance of three lettuce management programs for control of lepidopterous larvae. Conventional, experimental and biorational insecticides were sprayed to control beet armyworm, cabbage looper and Heliothis species throughout the growing season. Differences in populations of total larvae among the four treatments, relative to insecticide treatments and timing of application were observed throughout the season. In general, the standard and experimental treatments provided the most consistent control of lepidopterous larvae following each application. Harvest data showed that the spray regimes had a significant influence of head lettuce yield or quality. Maturity and quality were significantly reduced in the untreated control. An economic analysis shows that net returns varied widely among the management programs at different market prices. In conclusion, this study provides preliminary data to support the need for more development of experimental and biorational insecticide products as alternatives to conventional management programs in desert lettuce production.
    • Commercial Evaluation of Confirm for Control of Lepidopterous Pests of Lettuce using Various Applications Techniques

      Kerns, David L.; Tellez, Tony; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      Confirm was evaluated in head lettuce for control of lepidopterous pests when applied by air, and when applied by ground at 4, 8 and 12 mph. By air Confirm may not provide commercially acceptable control when used alone. Confirm must be ingested to exhibit activity and aerial applications may not provide adequate spray coverage. When used by ground, applicators should avoid exceeding 8 mph, again because good spray coverage may be compromised.
    • Commercial Evaluation of Proclaim for Control of Lepidopterous Pests of Lettuce

      Tellez, Tony; Kerns, David L.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      Proclaim 1.6 was evaluated in head lettuce in side-by-side large plot aerial and ground application demonstrations compared to commercial standard treatments. Proclaim consistently provided excellent control of beet armyworm and cabbage looper larvae. Worm control by Proclaim was equivalent to, or better than the commercial standards.
    • Mating Disruption of Beet Armyworm in Lettuce by Synthetic Pheromone

      Kerns, David L.; Tellez, Tony; Nigh, Jeff; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      The beet armyworm pheromone dispenser, Yotoh-con-S, was evaluated for its ability to inhibit mate location and subsequent population growth of beet armyworm in head lettuce. Pheromone dispensers were very effective in preventing male beet armyworm moths from locating point pheromone sources. Pheromone dispensers also appeared to result in an approximately 75 % reduction in beet armyworm larvae relative to untreated fields.
    • Review of New Insecticides Under Field Development for Desert Vegetable and Melon Production

      Palumbo, John C.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      The efficacy and field performance of new insecticides for control of insects on vegetables and melons under desert growing conditions has been investigated in small plot trials for the past several years at the Yuma Agricultural Center. Our objective has been to determine how new chemistries will fit into the growers management programs in Arizona. Thus, our research programs have been focused on studies to determine how to integrate these new chemicals into our local management programs in the most cost/effective way possible. This document was created to provide you with an overview of new insecticide chemistries being developed by the Agrichemical Industry for use in vegetables. The first part of this report concisely describes the new types of chemistries being developed The tabular information presented is a summary of the efficacy and activity of the new compounds based on research we have conducted at the Yuma Agricultural Center.
    • Lannate and Larvin Resistance in Beet Armyworms from the Low Desert Regions of Arizona and California

      Kerns, David L.; Tellez, Tony; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      Beet armyworm populations were collected in 1996-97 from spinach, melons, lettuce and alfalfa in Arizona and California, and tested for resistance to topical applications of Lannate. Resistance levels were found to be low to very high. The lowest level of resistance detected came from Blythe, CA, having no detectable resistance to Lannate, and from Parker, AZ, having a resistance level of approximately 24 fold. The highest level of resistance detected was a 685 fold increase, from a population collected from alfalfa in Imperial County, CA. In Yuma, larvae collected from alfalfa following an insecticide application that included Lannate, was 4.43 fold more resistant than the pre-application population. Only very low levels of resistance were found to Larvin, and no evidence of cross -resistance between Lannate and Larvin was found. Larvae resistant to topical applications of Lannate were found to be susceptible to Lannate given orally. Lannate resistance appears to be due to cuticular penetration and/or cuticular metabolism.
    • Comparison of Foliar-Applied Insecticides for Whitefly Control in Broccoli

      Umeda, K.; Murrieta, J.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      Whitefly (Bemisia tabaci also known as B. argentifolii) control in fall planted broccoli is difficult to achieve with foliar-applied insecticides and two treatments were compared and demonstrated a relative reduction of the immature stage of whitefly. Capture® (bifenthrin) plus Thiodan® (endosulfan) as a tank-mix applied two times significantly reduced the number of whitefly immatures (9/leaf) compared to the untreated check (71/leaf). Provado® (imidacloprid) following two applications reduced the number of immature whiteflies by only slightly more than 50% (38/leaf).
    • DPX-MP062 (DuPont) Insecticide Efficacy in Broccoli Study

      Umeda, K.; Stewart, D.; Murrieta, J.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      DPX -MP062 (Dupont) insecticide was applied two times in broccoli for cabbage looper (Trichoplusia ni. CL) control and demonstrated efficacy comparable or superior to methomyl (Lannate®) or esfenvalerate (Asana®). DPX-MP062 0.025 to 0.065 lb AI/A alone or in combination with Lannate significantly reduced the number of medium to large sized CL larvae relative to the untreated broccoli following each application.