Tobacco Insect Control with Insecticides Applied in the Transplant Water, 1995

Various insecticides applied as transplant water treatments were compared with foliar and soil treatments for TA and TFB control on flue-cured tobacco. Tests were conducted on a Chesterfield-Mayodan-Bourne sandy loam soil at the VPI & SU Southern Piedmont Agricultural Research and Extension Center, Blackstone, VA. Eleven treatments and an untreated control 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 9 May (soil temperature, 65 °F; ambient temperature, 70 °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 hr before transplanting. The treatment was applied with a CO2-pressurized backpack sprayer that delivered 1 fl oz of Admire 240FS 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 215 gal solution/acre with a Holland plunger-type transplanter on 16 May. The weather was sunny, and soil and ambient temperatures were 70 °F and 78-81 °F, respectively. Foliar applications of Orthene were applied on 3 Jul with a CO2-pressurized backpack sprayer that delivered 28 gpa at 60 psi through 3, TX-12 nozzles/row. The weather was clear, wind speed was less than 5 mph, and ambient temperature was 86 °F. Tobacco production followed Virginia Cooperative Extension recommendations for weed and disease control, fertilization, topping and sucker control. Dipel 4L was applied for tobacco hornworm control on 4 Aug. TA were counted on the upper 4 leaves of 10 plants/plot about once a wk from 6 to 10 wk after transplanting. On 22 Aug, TA damage was rated for each plot on a scale of 0 to 10 where 0 = no signs of aphid feeding and 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 22 May, 1 wk after transplanting. Tobacco was harvested as it ripened, weighed, graded by a USDA/AMS inspector, and yields and prices were calculated. Data were analyzed by ANOVA and significantly different means were separated by WD (K-ratio = 100). TA count data were transformed to Log10 (X+l) before analysis.