Control of Sugarcane Borer And Effects on Nontarget Arthropods, 1987

Abstract

Abstract Foliar spray concentrates were applied from an airplane to a field of plant cane (2 replicates) and first-stubble (2 replicates) sugarcane at Lannaux Plantation near Kilona, La., for evaluation of season-long control of borers in plots of a randomized block design with 4 replicates. Each spray concentrate was made in water at 25 psi (nozzles down and 45° back) to the crop canopy on 60-ft swath widths (10 rows) at a rate of 2 gal finished formulation/acre. A combination of 2 nozzle sizes was used, 22 of the D6-45 and D8-45, with an average density (drops/cm2) of 49.5 drops/cm2. The first application was initiated after internodes were visible aboveground and the SCB infestation exceeded the Louisiana State University recommended threshold of 5% of the stalks with live larvae in the leaf sheaths (13 Jul). The second application (17 Aug) was made when that level of infestation was again exceeded in Guthion-treated plots. Season-long control was evaluated 30 Nov (just prior to harvest) by examining 3 samples of 15 stalks randomly selected from the center of each plot for sugarcane borer entrance and adult exit holes. Relative survival inside the stalk was calculated as the ratio of exit holes to bored internodes. Nontarget ground-associated arthropods were continuously sampled with 2 pitfall traps centrally situated (50 ft apart) in each plot, changed monthly. Traps consisting of 1-pt jars filled with 2 inches 70% ethanol and 0.25 inches mineral oil were embedded on top of the row and covered by a 7-inch square plastic disk supported on a tripod 1 inch above the jar.