Insect Control on Flue-Cured Tobacco with Systemic Insecticides, 1994

Abstract

Abstract This experiment was conducted to evaluate various systemic insecticides applied as soil or transplant water treatments followed by foliar applications of Orthene for TA and TFB control on fluecured tobacco and to determine the impact of treatment on tobacco yield and price. The experiment was conducted at the VPI & SU Southern Piedmont Agricultural Research and Extension Center, Blackstone, VA. Eleven treatments and an untreated control were established in a randomized complete block design with 4 replications. Plots, 4 × 40 ft (1 row × 24 plants), were separated by single guard rows. Pretransplant soil treatments of most liquid formulations were applied broadcast with a CO2-pressurized tractor sprayer that delivered 30.4 gal/acre at 40 psi through 8003LP tips on 29 Apr (Ambient temperature, 85-89°F, soil temperature, 75°F; soil pH, 5.8; OM, 2%). Treatments were immediately incorporated by double disking. The Furadan and Temik treatments were applied during bed formation and immediately covered with 6 to 8 inches of soil on 17 May. 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. The soil moisture was good for both the pretransplant soil and bedding treatments. ‘K-326’ flue-cured tobacco was transplanted into experimental plots in a Chesterfield-Mayodan-Bourne sandy loam soil on 18 May. 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 each plant in the treatment plots. Virginia Cooperative Extension recommendations were followed for production of the crop. Foliar applications of Orthene and Dipel were applied on 6 Jul with a CO2-pressurized backpack sprayer that delivered 30 gal/acre through 3 TX-12 tips at 60 psi. TA populations were estimated on the upper 4 leaves of 10 plants/plot about once a week from 5 to 11 wk after transplanting. On 25 Aug, TA damage was rated on a scale of 0 to 10 where 0 = no aphid damage or sooty mold and 10 = very severe necrosis of leaves and extensive sooty mold. TFB 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 WD (K-ratio = 100). Aphid count data were transformed to Log10(x + 1) before analysis.