Experimental insecticides CGA-215944 (Ciba), pyriproxyfen (S-71639, Valent), and RH-7988 (Rohm and Haas) demonstrated very good efficacy in reducing the aphid population in cabbage. Fipronil (Rhone-Poulenc) was not as effective in controlling the aphids relative to the other treatments. Acephate (Orthene®), chlorpyrifos (Lorsban™), and naled (Dibrom®) were highly effective relative to the untreated check.

Three new insecticide chemistries (Alert, Spinosad and Confirm) were evaluated and compared with standard chemistries for temporal mortality of beet armyworm in lettuce. Field assessment and lab bioassay were conducted at the thinning, heading, and harvest stage of lettuce. Results from both the field and laboratory indicated similar trends for the temporal activity of the products. Alert appears to be have the most rapid "knockdown activity" with 100% mortality consistently occurring by 2 DAT. Spiniest, a naturalyte insecticide, has activity similar to Larvin. Both require 2-3 days to achieve complete larval mortality. Confirm, a new IGR selective for lepidoptera, requires significantly more time to achieve complete mortality (4-5 DAT). It can be compared with Bt (Xentari) activity in that it has initially slow activity. However, unlike Bt, it can effectively cause complete beet armyworm mortality. The results of this study are consistent with similar studies we conducted in 1994 and 1995 and provide basic guidelines concerning the activity and assessment of the performance of these materials in the field. However, PCAs and growers will ultimately be able to develop specific use patterns for these materials within their individual lettuce pest management programs.

Experimental insecticides MK-244 (Merck), Alert (AC 303630, Cyanamid), and Confirm (RH-5992, Rohm and Haas) demonstrated very good efficacy in reducing the lepidopterous pests including plutell4 xylostella (diamondback moth, DBM) and Tricoplusia at (cabbage looper, CL) in cabbage. The total number of small, medium, and large DBM larvae for all treatments was lower than the untreated at most rating dates. The experimental insecticides compared favorably with commercially available products Lannate®, Larvin®, and Kryocide®.

Imidacloprid (Admire®) was applied at planting time in anticipation of providing aphid control in cabbage for spring harvest. In three commercially treated cabbage fields, Admire reduced the number of cabbage (Brevicoryne brassicae) and green peach aphids (Myzus persicae). Two rates of Admire, 10 and 20 oz/A appeared to be similar in performance for efficacy against aphids. Depth of placement of Admire in the soil below the seed appears to have some influence on the efficacy and consistency of performance. Much fewer aphids and greater consistency was observed when Admire was placed at 1-inch depth below the seed compared to 3- to 4-inches below the seed.

Various rates of endosulfan and pennethrin were applied to cauliflower with electrostatic, hydraulic air- assist and conventional hydraulic spray systems. Sweetpotato whitefly abundance and plant growth were measured at several intervals during the study. In addition, spray coverage was measured with each insecticide application. No differences in whitefly control or spray deposition were observed among the three sprayers. However, imidacloprid, provided excellent control. The significance of the spray technologies for whitefly control and future modifications are discussed.

Beauveria bassiana is a naturally occurring fungal disease of insects that has been shown to be an effective biological control against whiteflies in cotton and vegetable crops. Six treatments were initiated in drip irrigated fall cantaloupe on October 2, and repeated on October 9 and 23. The six treatments consisted of 1) a check or unsprayed plot; 2) 0.5 lb. Mycotrol WP/acre; 3) 1 Ib. Mycotrol WP /acre; 4) 1 pt. Mycotrol ES/acre; 5) 0.5 lb. Mycotrol WP /acre + pyrethroid tank mix; and 6) 12 oz. Naturalis-L/acre. Under moderate to light sweetpotato whitefly pressure, the Mycotrol formulations provided significant control (68-79%) compared to unsprayed check plots, and were superior to Naturalis-L formulation whose effects were relatively short lived. Mycotrol WP applied in three applications at the labeled rate of 1 lb. product/acre had the cumulative effect of maintaining adult whitefly leaf counts below the currently recommended economic threshold of 3 per leaf at 28 days after treatment initiation, under the conditions of this study.

Three new insecticide chemistries (Alert, Success and Confirm) were evaluated and compared with standard chemistries for residual activity to beet armyworm in lettuce. Lettuce was treated in the field with the insecticides and left for 0, 3, 5 and 7 days. Leaves from treated plants were then brought into the laboratory where second instar beet armvworms were reared on them. Mortality was estimated 5 days after the worms were placed on the leaves. Bioassay were conducted at the thinning, heading, and harvest stages of lettuce. Under high temperature and light intensity, only Alert and Confirm provided the best residual control of beet armyworm, exhibiting good activity for about 3 days after application. Success had better residual activity than Lannate, and both were better than Xentari. Under cool temperatures and low light intensity conditions, Alert, Confirm and Larvin exhibited good activity for at least 5 days following an application, (7 days or greater for Alert and Confirm). Lannate and Xentari both had greater residual activity late in the season, but were not as effective as Alert, Confirm or Larvin. Late season activity of Success did not appear to differ much from early season observations, and did not appear to provide more than 3 days residual activity.

A study was conducted in 1995 to evaluate five application technologies in the field in terms of deposition efficiency, as well as to assess their abilities to control the sweet potato whitefly and thereby influence crop yield. The FMC and ESS-on treatments provided the greatest deposition on the ventral side of the leaves. The FMC system tended to maintain high ventral deposition efficiencies as the plants grew and the canopy closed, whereas the efficiency of the ESS declined. Differences in ventral deposition efficiency among treatments were not closely associated with differences in whitefly control, although the declining rate of ventral deposition for the ESS-on is also reflected in its declining superiority in adult insect control relative to the CDA and conventional systems. The ESS sprayer provided somewhat better whitefly control than the conventional treatment, and was also associated with a higher yield of #12 melons than the control and Admire treatments, but not better than the conventional treatment. Early control of adults was associated with reduced egg counts later in the season, suggesting that there may be long term control advantages with the ESS system. New application technologies need to be developed to obtain higher ventral deposition and maximum whitefly control, with minimum use of insecticides.

Several experimental insecticide treatment combinations were evaluated and demonstrated very good efficacy against Bemisia argentifolii [silverleaf whitefly (WF) also known as sweetpotato WF, B. tabaci]. Adults and immatures were most effectively reduced compared to the untreated check by pyriproxyfen (S-71639, Valent) treatments and fenpropathrin (Danitol®) plus acephate (Orthene®). CGA-215944 (Ciba) plus fenoxycarb (Ciba) treatments compared favorably with many of the pyrethroid combination treatments. Registered products esfenvalerate (Asana®), endosulfan (Thiodan®), cypermethrin (Ammo®), naled (Dibrom®), and oxydemeton-methyl (Metasystox-R®) complemented many of the combination treatments to reduce WF relative to the untreated check

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.