Control of Early-Season Insects on Tomatoes, 1987

Abstract

Abstract Tomato seedlings were transplanted on 28 May. Orthene 75 SP was applied as a transplant-water treatment at the rates of 1.0, 1.5, 2.0, and 3.0 lb (AI)/acre, using 4.5 oz water/plant. Plots were 23 by 7 ft, replicated 4 times in a randomized complete block design. Each plot consisted of 2 rows of tomatoes with 23 plants in each row. Effectiveness of the treatments for DCW control was evaluated by counting the number of damaged plants in each plot 2-wk after transplanting. Toxicity and residual activity of Orthene against sixth- to seventh-instar DCW were tested by collecting random leaf samples from each plot beginning 1 d after transplanting and then weekly for 3 wk. Samples were taken to the laboratory and equal amounts of leaves were placed in 4-inch Petri dishes containing insecticide-free sand and 10 larvae. Mortality was assessed daily for 4 d by counting the number of dead larvae in each dish. Abbott's formula was used to correct for the mortality occurring in the untreated control. For evaluation of PFB control, 20 leaves were collected at random from each plot 3 wk after transplanting, and the number of feeding holes on each leaf was counted. To assess for GPA control, 20 leaves were collected at random from each plot 3 and 6 wk after transplanting, and the number of living GPA on each leaf was counted under a magnifier in the laboratory. The mortality percentages of the cutworms were transformed to angular units. The logarithmic transformation was used for the aphid counts. The number of PFB feeding holes on the leaves and DCW-damaged plants in each plot was transformed to x + 0.5 before ANOVA. Mean values were converted to original units for presentation in the table.