EVALUATION OF ADMIRE FOR THE CONTROL OF CUCUMBER BEETLES AND BACTERIAL WILT IN PUMPKIN, 2000

This study was undertaken to evaluate Admire for controlling bacterial wilt as well as cucumber beetles, for which it was recently labeled. Evaluation included comparison with the industry standard of weekly foliar applications of Sevin. Cucumber beetles vector Erwinia tracheiphila, the causal agent of bacterial wilt. An experiment was conducted at the Long Island Horticultural Research and Extension Center in Riverhead, NY, in a field of Haven loam soil. Fertilizer (1000 lb/acre of 10-10-10) was broadcast and incorporated on 30 May. To manage Phytophthora fruit and crown rot, Ridomil Gold EC (1 pt/acre) was broadcast over the entire field then incorporated on 31 May. The herbicides Curbit EC (1 pt/treated acre) and Command 4EC (4 pt/treated acre) were applied on 21 Jun in a 10-inch band over the planted rows, then incorporated by irrigating. Average monthly high/low temperatures (F) were 81/61 in Jun, 81/64 in Jul, and 81/65 in Aug. Rainfall (inches) was 4.24, 4.7, and 2.42 for these months, respectively. The field was irrigated (» 1.0 inch) on 6-7 Jul and 13 Jul. Treatments were randomized in four complete blocks. The wilt-susceptible cultivar ‘Merlin’ was selected. Plots were double 12-ft rows each with five plants spaced 30 inches apart in rows spaced 11.3 ft apart. Plots were spaced 13 ft apart in the row. Seeding was done by hand on 20 Jun. A tractor-drawn Cole planter was used to open the furrow and a hand push-hoe was used to close the furrow after seeding. Admire was applied at 1.1 fl oz/1000 linear ft of row after seeding, using a CO2-pressurized backpack sprayer and hand-held boom equipped with a TeeJet TJ-60 4003 EVS twinfan nozzle. Two methods for applying Admire were compared: in the furrow with the seed (20 Jun) and in a 2-inch band over the row after closing the furrow (21 Jun). Herbicides were applied on 21 Jun, followed by irrigation (about 0.25 inches). Admire was also applied in furrow followed by four weekly applications of Sevin XLR during Aug. Applications of Sevin were originally planned to be started when the action threshold of 1 beetle/plant was reached. However this did not occur. Foliar application of Sevin XLR and Avaunt 30WG were made weekly from emergence (1, 8, 15, 21, and 29 Jul; and 4, 11, 18, and 25 Aug). The first six applications were made using a CO2-pressurized backpack sprayer and hand-held boom equipped with TeeJet TJ-60 4003 EVS twinfan nozzles that delivered 60 gpa at 30 psi. The boom was equipped with one nozzle while plants were small. Three nozzles were used beginning on 15 Jul. The remaining applications were made with a tractor-mounted boom sprayer equipped with D3-45 hollow cone nozzles spaced 11 inches delivering 100 gpa at 210 psi. Plants were examined weekly for live and dead cucumber beetles, feeding damage, and symptoms of bacterial wilt. Wilt severity of each plant was assessed weekly from 5 Jul through 5 Sep as percentage of plant wilted. Wilt incidence in each plot was calculated for plants that were at least 50% wilted. Pathogen presence was confirmed by examining thin sections from stems of wilted plants.