FOLIAR SPRAYS FOR FLEA BEETLE AND APHID CONTROL ON FLUE-CURED TOBACCO, 2000

Abstract

This experiment was conducted at the Southern Piedmont AREC, Blackstone, VA, to evaluate various foliar insecticides for GPA and TFB control and to assess the resulting effects on the economic value of fluecured tobacco. Tobacco 'K 326' was transplanted into experimental plots on 10 May. Seven treatments and an untreated check were established in a RCB design with four replications (Table 1). Plots, 4 x 40 ft (1 row x 24 plants), were separated by single untreated guard rows. Treatments were applied as foliar sprays with a CO2-pressurized backpack sprayer that delivered 25 gpa at 50 psi through TX-10 nozzles (3 per row) on 19 May, 21 Jun, and 2 Aug. Temperatures during application ranged from 84-88 oF on 19 May, 82-84oF on 21 Jun, and 85-88oF on 2 Aug. After the 19 May application, 0.42, 0.13, and 0.52 inches of rain fell at 1, 2, and 3 DAT. No significant rainfall occurred within the first week after the sprays on 21 Jun and 2 Aug. TFB and TFB feeding holes on the most damaged leaf were counted on five plants/plot at 4, 7, and 12 d after the 19 May applications. GPA counts were made on the upper four leaves of 10 plants/plot about once a week from 30 Jun to 9 Aug. Normal production practices were followed for weed and disease control, fertilization, and topping. Spinosad 4L was applied at 2 fl oz/acre to the entire test for tobacco hornworm control on 21 Jun and 3 Aug. Tobacco was harvested as it ripened. It was cured, weighed, and graded by an USDA/AMS inspector, and gross economic returns were calculated in $/acre. Gross economic values were based on market prices for the assigned grades in 2000. Data were analyzed by ANOVA and significantly different means were separated by WD test (P = 0.05). GPA and TFB feeding hole count data were transformed to Log10(X+1) before analysis. Actual means are presented in the tables.