Spanworm Control, 1996A

Materials were applied on 22 May to 20 by 20 ft plots in a bearing blueberry field at Jonesboro, Maine. There were 4 replications of each treatment and a minimum 5-ft untreated buffer strip around each plot. Treatments were blocked according to prespray population levels. Insecticides were applied at a rate of 25 gpa using a CO2-propelled 40-inch boom sprayer with 4, flat spray, 800067 TeeJet nozzles operating at 35 psi (Test 1) or a CO2-propelled 80-inch boom sprayer with 4, flat spray, 80002VS TeeJet nozzles operating at 30 psi (Test 2). At treatment, larvae were first to third instar and plants were ca. 10% swollen bud, 40% tight cluster, 50% loose cluster. On sample dates indicated in table, 10 sweeps with a standard 12-inch sweep-net were taken systematically through the center area of each plot avoiding plot boundaries. The larvae were counted and then distributed back into the same plot. High winds on 27 and 28 May made sweep-net sampling difficult and may have confounded the results for those two dates.