Abstract
Various insecticides applied as transplant water treatments were compared with foliar and soil treatments for TA and TFB control and for their effects on the yield of flue-cured to bacco. Tests were conducted on a Chesterfield-Mayodan-Bourne sandy loam soil at the Southern Piedmont Agricultural Agric. Res. and Ext. Cntr., Black-stone, VA. Eleven treatments and an untreated check were established in a RCB design with 4 replications. Plots, 4 X 40 ft (1 row X 24 plants), were separated by single untreated guard rows. The Temik treatment was applied in a 14-inch band using a tractor mounted-Gandy granular applicator and immediately covered with 6 inches of soil at bed formation on 21 May (soil temperature 75 °F ambient temperature, 88 °F, soil pH, 5.6; weather, sunny; soil moisture, good). The Admire drench treatment was applied to tobacco seedlings in 288-cell float trays 24 hrs before transplanting. The treatment was applied with a CO2-pressurized backpack sprayer that delivered 1 fl oz of Admire 240 FS in 1.84 gal of water/1,000 plants through 8003LP tips at 20 psi. Treatments were watered in with an additional 1 gal of water immediately after application. ‘Coker 371 Gold’ flue-cured tobacco was transplanted and the transplant water (TPW) treatments were applied in 204 gal solution/acre with a Holland plunger-type transplanter on 21 May. The weather was sunny, and soil and ambient temperature was 75 °F and 88-91 °F, respectively. Foliar applications of Orthene were applied on 3 Jul and 8 Aug with a CO2-pressurized backpack sprayer that delivered 28 gpa at 60 psi through TX-12 nozzles (3 per row. The weather was clear, wind speed was less than 5 mph, and ambient temperature was 84-86°F at each application. Except for insect control, tobacco production followed Virginia Cooperative Extension recommendations. Dipel 4 L (Bacillus thuringiensis) was applied for tobacco hornworm control on 3 Jul. TA were counted on the upper 4 leaves of 10 plants/plot about once a week from 6 to 10 wks after transplanting. On 22 Aug, TA damage was rated for each plot on a scale of 0 to 10: 0 = no signs of aphid feeding; 10 = all leaves showing severe damage resulting from TA infestations including honeydew, sooty mold, necrotic leaf tissue, and exuviae. TFB feeding holes were counted on 5 plants/plot on 2 and 26 Jun, 2 and 5 wks after transplanting. Tobacco was harvested and cured and yield was determined. Data was analyzed by ANOVA and significantly different means were separated by Waller-Duncan K-ratio t-test (K = 100). TA count data were transformed to log10 (x + 1) before analysis.
SYSTEMIC INSECTICIDES APPLIED AS SEEDLING DRENCH AND TRANSPLANT WATER TREATMENTS FOR INSECT CONTROL ON FLUE-CURED TOBACCO IN VIRGINIA, 2010