Aphid and Flea Beetle Control on Tobacco with Insecticides Applied in the Transplant Water, 1997

Abstract

Abstract Various insecticides applied as transplant water treatments and transplant drench (TPD) were compared with foliar and soil treatments for TA and TFB control and for the impact of treatment on yield of flue-cured tobacco. Tests were conducted on a Chesterfield-Mayodan-Bourne sandy loam soil at the Southern Piedmont Agric. Res. and Ext. Cntr., Blackstone, VA. Eleven treatments and an untreated check 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 15 May (Ambient temperature 75-78 °F, soil 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 hrs before transplanting. The treatment was applied with a CO2-pressurized backpack sprayer that delivered the desired rates of Admire 240 FS in 0.46 gal of water/1,000 plants through 8003LP tips at 20 psi. Treatments were watered in with about 1 gal of water immediately after application. ‘Coker 371 Gold’ flue-cured tobacco was transplanted and the transplant water (TPW) treatments were applied in 204 gpa with a dipper at 4 fl oz/plant on 20 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 11 and 31 Jul with a CO2-pressurized backpack sprayer that delivered 30 gpa at 50 psi through 3 TX-12 nozzles/row. Except for insect control, tobacco production followed recommendations of the Virginia Cooperative Extension Service. Dipel 4 L (Bacillus thuringienis) was applied for tobacco hornworm control on 3 Jul. TA were counted on the upper 4 leaves of 10 plants/plot about once a week from 6 to 10 wks after transplanting. On 22 Aug, TA damage was rated for each plot on a scale of 0 to 10: 0 = no signs of TA feeding; 10 = all leaves showing severe damage resulting from TA infestations including hon-eydew, sooty mold, necrotic leaf tissue and exuviae. TFB feeding holes were counted on 10 plants/plot at 2 to 4 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 Waller-Duncan K-ratio t-test (K = 100). TA count data were transformed to log10 (x + 1) before analysis.