Effects of Tank Mix Combinations of Insecticides and a Herbicide on Cutworms, Weeds, and Flue-Cured Tobacco, Ontario, Canada, 1985

Each of the 3 insecticides and a herbicide, Enide, were applied in tank-mixed combinations on tobacco seedling; after transplanting to determine their effects on cutworms, weeds, and on the yield and quality of flue-cured tobacco in Ontario. Tobacco seedlings of the variety Candel were transplanted into a field of Fox loamy sand on 28 May. Plots were 76 × 14 ft, replicated 4 times in a randomized block design, anc consisted of 4 rows with 38 tobacco plants in each row. Furthermore, 2 subplots (12 × 12 inches each) containing 3 tobacco seedlings were established ir each plot. Ten 6th and 7th-instar larvae were introduced in each subplot 2 h before treatment and then 5 days after treatment. The larvae were retained in the subplots by aluminum barrier strips 8 inches high with 3 inches embedded in the ground to prevent the cutworm larvae from escaping. The tank mixtures of insecticides and Enide were applied in a 10-inch band over the row in each plot on 5 Jun, using a power sprayer equipped with 65-06 flat nozzles applying 11 gal of liquid per acre at 15 psi and 3.5 mph speed. Cutworm damaged plants from the 2 central rows in each plot were counted weekly after treatment for 4 weeks and the number of weeds was counted 2 weeks after treatment. Mortality counts of the larvae in the subplots were made daily for 5 days. Abbott’s formula was used to correct for the mortality occurring in the check. The harvest and curing of each plot were carried out in the conventional manner. Cured tobacco leaves were analyzed for reducing sugars and total alkaloids as measures of the quality of the tobacco. Agronomic parameters measured were yield (lb/acre) and grade index (0/lb). The percentages of larval mortality in the subplots were transformed into angular units, and square root transformation VX + 0.5 was used for the number of cutworm damaged plants before analysis of variance. Means were converted to original units of presentation in the table.