No description available.

No description available.

No description available.

No description available.

No description available.

A field study was conducted at Yuma in 1991 to examine the relative effectiveness of several formulations of Bacillus thuringiensis on beet armyworm and cabbage looper on seedling and pre-cupping lettuce. Several applications were made before and after thinning. Results of the study suggest that most formulations are capable of controlling small larvae. However, because of the inherent variation in beet armyworm dispersion, it was difficult to statistically attribute differences in pest levels due to insecticide efficacy.

No description available.

No description available.

The effects of Admire formulation and soil placement on colonization by sweetpotato whitefly, Bemisia tabaci (Gennadius), at three plant growth stages of lettuce, Lactuca sativa L., were evaluated in experimental and commercial lettuce plots in 1993-1994. We also evaluated the effects of Admire treatments on yield response and incidence of chlorosis associated with whitefly control. Admire placement had a significant affect on whitefly colonization in lettuce throughout the experimental period. Whitefly densities on lettuce varied at each plant stage relative to depth of placement within the lettuce seed bed. Applications made to the soil surface and at 1.5 inch sub-seed furrow followed by irrigation, provided the most consistent control of whitefly nymphs in both small plot and on -farm lettuce plots. These Admire soil treatments also prevented reductions in head size and incidence of leaf chlorosis associated with whitefly colonization in lettuce. Our data suggest that incorporation of Admire into the upper 1.5 - 2 inches of soil below the seed furrow is optimal for absorption and translocation by lettuce roots. Admire soil treatments may provide a more environmentally suitable and effective alternative to control of whiteflies in lettuce than is currently possible with foliar insecticide reatments.

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.