CONTROL OF SILVERLEAF WHITEFLY AND INCIDENCE OF TOMATO YELLOW LEAF CURL VIRUS ON STAKED TOMATO WITH INSECTICIDES AND RESISTANT VARIETIES, 2006

Reduced yield due to whitefly-borne tomato yellow leafcurl virus (TYLCV) is a major constraint to tomato production in southwest Florida. Integration of insecticidal control and disease resistant varieties would provide benefits of both management tactics to avoid yield loss. On 22 Feb, tomato seedlings from a commercial greenhouse were transplanted at 18-inch spacing on 2 sets of 3beds 240 ft in length and covered with polyethylene film mulch, black side up. The center bed in each set of 3 was planted in the TYLCV-susceptible ‘Florida 47’ and left untreated to serve as the untreated check and as source of whiteflies and virus. The remaining 8 treatments (Table 1) were randomized among 31 ft. plots in a complete block design replicated 4 times. Liquid formulations of Platinum and Admire Pro were applied as soil drenches in 50 ml of solution 2 days later. Approximately 20% of the fertilizer was preplant soil incorporated with the remaining 80% applied through drip irrigation. Foliar sprays were applied with a single row high clearance sprayer operating at 200 psi and 2.4 mph with the spray delivered through two vertical booms fitted with yellow Albuz® hollow cone nozzles, each delivering 10 gpa. Two nozzles per boom were used to apply 40 gpa when plants were small, additional nozzles being added later to maintain spray coverage to a maximum of 4 nozzles per boom to deliver 80 gpa. As nozzles were added, concentration was adjusted to maintain a constant product rate per acre. Fungicides Kocide and Manzate 75 DF were applied weekly to control foliar diseases at rates of 3 lbs and 1.5 lbs per 100 gal, respectively. Eleven weekly evaluations of whitefly adults were made beginning 15 Mar by beating 1 side of 8 plants per plot with a 9 x 13 inch pie pan painted black and coated with spray-on oil. Immature stages were monitored 10 times weekly beginning 30 Mar by counting all whitefly stages appearing in a 2 cm area ring placed on each leaflet of the 3 terminal leaflets collected using 1 trifoliate leaf removed from the 6th node of 4 centrally located plants in each plot. Plants were evaluated weekly for the presence of TYLCV symptoms. Fruit was harvested weekly for 5 weeks from the 8 plants per plot beginning 4 May. Number and weight of marketable fruit and culls were recorded.