Insect Control on Flue-Cured Tobacco with Systemic Insecticides, 1995

Abstract

Abstract This experiment was conducted at the VPI & 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 and to determine the impact of these treatments on tobacco yield and price. Twelve 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 guard rows. Pretransplant soil treatments of most liquid formulations were applied broadcast with a CO2-pressurized tractor sprayer that delivered 32 gpa at 30 psi through 8003LP tips on 8 May (ambient temperature 74–76 °F, soil temperature, 70 °F; soil pH, 5.7; OM, <2%). Treatments were immediately incorporated by double disking. Band applications of Furadan and Temik were made during bed formation and immediately covered with 6 to 8 inch of soil on 8 May. Furadan 4F band treatments were applied in a 12-inch band using a CO2-pressurized backpack sprayer that delivered 16 gpa through an 8003E tip at 30 psi. Temik was applied in a 14-inch band using a tractor mounted-Gandy granular applicator. The soil was in excellent condition 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 17 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 each plant in the treatment plots. Virginia Cooperative Extension recommendations were followed for fertilization, topping, and weed disease, and sucker control. Dipel (Bacillus thuringiensis) was applied for tobacco hornworm control on 28 Jul. The foliar application of Orthene was applied on 3 Jul with a CO2-pressurized backpack sprayer that delivered 28 gpa through 3 TX-12 tips at 60 psi. TA populations were estimated on the upper 4 leaves of 10 plants/plot about once a wk from 5 to 9 wk after transplanting. On 25 Aug, TA damage was rated on a scale of 0 to 10 where 0 = no signs of aphid damage and 10 = very severe necrosis of leaves and extensive sooty mold. TFB and TFB feeding holes were counted on 5 plants/plot. Tobacco was harvested as it ripened, weighted, graded by a USDA/AMS inspector, and yield was 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.