Cabbage Looper Control on Head Lettuce with Bacillus and Pyretroids, 1978

Abstract

Abstract Plots for this study were located on the University of Arizona, Mesa Branch Station. Soil type is Laveen Clay loam. Empire variety of lettuce (naked seed) was planted on Aug 25. Planting was with a vegetable sled on 40 inch wide beds, with 2 plant rows per bed. Seeding was in a dry seed bed and the planting was furrow irrigated, keeping the beds damp until germination occurred. Plants were thinned to 12 inch spacing on Sep 25. Plots were 4 (40 inch) beds wide × 25 ft long representing 0.007 acre. All treatments were replicated 4 times using a complete randomized block design. Sprays were applied with a CO2 pressurized spray unit mounted on an International 284 tractor which treated 4 beds at one time. When the plants were small a single hollow cone nozzle was used/plant row. The system was operated at 60 psi, applying 35 gallons of spray mixture per acre. After the plants increased in size, 2 hollow cone nozzles/plant row were used. All insect counts were made from the middle 2 beds of each plot. Ten plants were examined and the number of cabbage looper eggs and larvae were recorded per plot. Yield data was taken from the middle 2 beds of each plot. The total number of plants in the two beds was recorded after which the mature heads were field graded according to #l 1/2, #2 and #2 1/2 sized heads. These numbers indicate the number of dozen heads that can be packed in a standard shipping carton.