EVALUATION OF FOLIAR INSECTICIDES FOR THE CONTROL OF ONION THRIPS IN DRY-BULB ONION, 2010

摘要: The objective of this experiment was to assess the efficacy of foliar insecticides applied at-threshold to control immature stages of OT in dry-bulb onion. The trial consisted of 17 main effect treatments arranged in a RCBD with four experimental replicates. Onion was direct seeded 20 May 2010 in a cooperating producer’s field located 5.1 miles (8.1 km) west of Coloma, Wisconsin on a muck soil. Experimental plots consisted of single 56 inch (1.4 m) beds containing 6 rows of onion spaced 9.8 inches (24.9 cm) between rows and 2.2 inches (5.6 cm) within rows and experimental plots measured 25 ft (7.6 m) in length with planted beds on either side acting as guard rows. All foliar treatments were applied in 1.0 L of water at 24.9 gpa using a four nozzle, 6 foot (1.8 m) boom equipped with an XRVS 8003 flat fan spray tip powered by a CO2 backpack sprayer operating at 30 psi. Successive applications were initiated when mean immature thrips populations had exceeded established thresholds of 3 immature thrips/leaf and the foliar applications were applied 22 and 29 Jun. Applications on 22 Jun occurred between 10: 00-11: 30 hours and application conditions were recorded as a west wind at 3.8 mph (6.1 kph), 72 F (22.2 C), 80% RH, under mostly cloudy conditions with a 3 inch (7.6 cm) soil temp at the time of application of 69 F (20.6 C). Applications on 29 Jun occurred between 8: 00-9: 30 hours and application conditions were recorded as a west wind at 4.5 mph (7.2 kph), 69 F (20.6o C), 80% RH, under mostly cloudy conditions with a 3 inch (7.6 cm) soil temp at the time of application of 70 F (21.1 C). All plots were maintained according to standard …