Cabbage Looper Control on Cabbage, 1977

Abstract ‘Golden Acre YR’ cabbage seed was planted August 11, 1977, using a Stanhay precision planter, which planted 2 seed rows per 40-inch bed. Planting was in Laveen clay loam soil, in a dry seed bed and the crop furrow irrigated. Plants were thinned on September 14 to 14-inch spacing. Plots were 4 beds wide and 25 ft long. Each treatment was replicated 4 times in a complete randomized block. Spray applications were started September 15 and were made at approximately weekly intervals for a total of six treatments. Sprays were applied using a 2-gallon, CO2-pressurized, back-pack sprayer with a 2-nozzle boom operating at 50-55 psi and delivering 35 gallons of spray per acre. A single, hollow-cone nozzle was used per row on the young plants. As the plants became larger, 2 nozzles per row were employed. Effectiveness of the different materials was determined by counting the cabbage looper eggs and larvae on 10 plants from the middle two beds of each plot. Looper damage evaluation was made on plants in the middle 2 beds of each plot. A 1-5 rating scale was used: 1 indicating no damage and 5 indicating heavy damage. Cabbage looper populations began early and persisted throughout the season. There was extremely heavy population pressure present this year, which is indicated by counts as high as 191 eggs per 10 plants, early in the season. Although larvae counts were high for some treatments, such as 29 per 10 plants for Ambush and 21.8 for Lannate, most of these larvae were first and second instar with few reaching the larger instars. FMC-45498 appeared to be the most effective material in this trial.