Tobacco Insect Control with Systemic Insecticides, 1993

Abstract

Abstract This experiment was conducted at the VPI and SU Southern Piedmont Agricultural Research and Extension Center, Blackstone, VA, to evaluate TA and TFB control on flue-cured tobacco with various systemic insecticides applied as soil or transplant water treatments. Fourteen treatments and an untreated control were established in a RCBD with 4 replications. Plots, 8 × 40 ft (2 rows × 24 plants), were separated by single untreated guard rows. Pretransplant soil treatments of most liquid formulations were applied with a CO2-pressurized tractor sprayer that delivered 34 gal/acre and 30 psi through 8003LP tips spaced 20 inches apart on 3 May. Soil treatments applied before bedding were immediately incorporated by double disking. The Di-Syston, Furadan, and Temik treatments were applied during bed formation on 11 May. Di-Syston was applied in a 20-inch band using the tractor-mounted CO2-pressurized sprayer that delivered 17 gal/acre immediately in front of the bedder. Furadan 4F was diluted 50:50 in water and applied in a narrow stream (<1 inch wide) in the row using a peristaltic pump. Temik was applied in a 14-inch band using a tractor mounted-Gandy granular applicator and immediately covered 6 inches of soil at bed formation. The soil was in excellent condition for both the pretransplant soil and bedding treatments. A measuring cup was used to apply transplant water (TPW) treatments of Orthene and Admire in 4 fl oz/plant (204 gal/acre) at the base of newly transplanted plants. The flue-cured tobacco was transplanted into experimental plots in a Chesterfield-Mayodan-Bourne sandy loam soil on 12 May. Virginia Cooperative Extension Recommendations were followed for production of the crop. The test was irrigated with 1 inch of water on 28 Jun, 14, 22 and 28 Jul. Bacillus thuringiensis (Dipel) was applied on 25 Jun and 6 Aug for control of hornworms and budworms. TA populations were estimated on the upper 4 leaves of 10 plants/plot about once a week from 4 to 12 wk after transplanting. TFB on one side of a plant and TFB feeding holes in the most damaged leaf were counted on 10 plants/plot. Tobacco was harvested as it ripened, weighed, graded by a USDA/AMS inspector, and yield and price were calculated. Data were analyzed by ANOVA and significantly different means were separated by DMRT. Aphid count data were transformed to Log10(x + 1) before analysis.