r&?6m N F 5 ._ t .... ..--.-- ----", _( /-7 NORTH FLORIDA RESEARCH AND EDUCATION CENTER Ir'. - Quincy, Florida iar AGRICULTURAL RESEARCH AND EDUCATION CENTER Live Oak, Florida Quincy NFREC Research Report NF-88-12 Chemical Control of Insects Attacking Flue-Cured Tobacco in 1988__-- William B. Tappan, Entomologist, Quincy,-and Jimmie R. Rich, Nematologist, Live Oak MATERIALS AND METHODS Nine chemical foliar spray treatments were field tested on Northrup King K-326 flue-cured tobacco for insect control, phytotoxicity, effect on crop yield and value, and insect resistance to certain treatments. Formulations, number of applications, and dosage of active ingredients per acre per applica- tion are presented in Table 1. The dates treatment applications were made are given in a footnote in Tables 1 through 6. Spray treatments were applied at 14-day intervals with a tractor-mounted CO2-pressurized sprayer with one hollow-cone nozzle over each row and one hollow-cone nozzle on each side of the row. The three Tee-Jet D3- 25 nozzles per row were designed to deliver approximately 26 gallons of spray per acre at 60 p.s.i. and 4 m.p.h. Treatments were replicated three times in complete randomized blocks. Each plot was two rows wide, and was separated by a 5-foot vacant alley or buffer zone between plots within a block. The rows were 40 feet long and 3.67 feet apart within plots. Both rows served as the experimental plot for insect counts, phytotoxicity ratings, crop yield, crop value, and insect resistance to certain treatments. Each row contained 24 to 25 plants set on approxi- mately 19-inch centers. Alleys between blocks of plots were 20 feet wide. The test was located northeast of the barn area of the Center. All cultural practices in preparing the test area for planting were per- formed in the usual manner. Beds for planting were prepared and fertilizer applied in late February. The tobacco was transplanted on March 21, 1988, and hand-topped on May 31. A sucker control, Royal-Tac, was applied at 2 gallons per acre on June 2, followed by hand suckering on June 9, and an additional application of MH-30 at 1.5 gallons per acre on June 10. Green peach aphid counts were made from natural infestations beginning on April 25 (pretreatment count), and succeeding counts followed at 14-day inter- vals. All counts were made by counting the number of live alate and apterous aphids on four leaves three inches or longer down from the bud. Five marked plants equidistant from each other in each of the experimental rows were counted. Counts of tobacco budworm and tobacco hornworm were made from natural infestations on April 25 (pretreatment count), and all succeeding counts were made on the same dates as aphid counts. Each plant in each plot that had at least one larva and the characteristic feeding injury of the species was counted as a damaged plant.