Insect Control of Flue-Cured Tobacco with Systemic Insecticides, 1997

Abstract

Abstract This experiment was conducted at the Southern Piedmont Agric. Res. and Ext. Cntr., 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. Thirteen treatments and an untreated check were established in a RCB design with 4 replications in a Chesterfield-Mayodan-Bourne sandy loam soil. Plots, 4 X 40 ft (1 row X 24 plants), were separately by single guard rows. Pre-transplant soil treatments of all liquid formulations except Furadan were broadcast with a CO2-pressurized tractor sprayer that delivered 32 gpa at 30 psi through 8003 LP tips on 13 May (Ambient temperature 66-68 °F, soil temperature, 65 °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 15 May (Ambient temperature 75-78 °F, soil temperature, 70 °F). Furadan 4°F 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. ‘Coker 371Gold’ flue-cured tobacco was transplanted into experimental plots on 19 May. A measuring cup was used to apply transplant water (TPW) treatments of Orthene and Admire in 4 fl oz/plant (204 gpa) at the base of each plant in the treatment plots. Except for insect control, production practices followed Virginia Cooperative Extension recommendations. Dipel (Bacillus thuringiensis) was applied for tobacco budworm and tobacco hornworm control on 3 Jul. Foliar applications of Orthene were applied to the Orthene TPW treatment on 5 and 31 Jul and to the Furadan treatment on 19 Jul using a CO2-pressurized back-pack sprayer that delivered 30 gpa through TX-12 tips (3 per row) at 50 psi. TA populations were estimated on the upper 4 levels of 10 plants/plot every 6 to 12 days from late Jun to mid Aug. On 25 Aug, TA damage was rated on a scale of 0 to 10: 0 = no signs of damage; 10 = very severe necrosis of leaves and extensive sooty mold. TFB and TFB feeding holes were counted on 10 plants/plot at 1 to 4 wks after transplanting. Tobacco was harvested as it ripened, weighted, and yield was calculated. Data were 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. Actual means are presented in the table.