CONTROL OF SILVERLEAF WHITEFLY IN STAKED TOMATO WITH SOIL-APPLIED INSECTICIDES, AND FOLIAR SPRAYS, 2004

Populations of silverleaf whitefly and incidence of whitefly-borne TYLCV continue to increase in southwest Florida and with it the dependence on soil-applied neonicatinoid insecticides to provide the control upon which profitability is so dependent. It is therefore of interest to examine additional options to supplement these all-important systemic insecticides. Seedlings from a commercial greenhouse were transplanted 31 Mar at 18-inch spacing on eight drip-irrigated beds, 240 ft long on 12-ft centers. The beds were divided into consecutive two bed sets to make four replications with each divided into 12 plots, each 40 ft long and assigned to treatments in a RCB design. The Admire 2F, Platinum 2SC and Assail WP treatments were applied as soil drenches on 2 Apr in 10 ml of solution. Admire 2F was also applied as a soil drench at 16 fl oz product/acre on 13 Apr to plants receiving Root Feed and those receiving one of three rates of the horticultural mineral oil (HMO). Root Feed I an II were alternated and applied weekly from 5 Apr until harvest for a total of eight applications. Root Feed I was applied at a rate of 5 gal product/acre and Root Feed II at 15 lbs product/acre in a soil drench to each plant in 30 ml of solution. The Oberon 2 SC was applied 11 May, for three weekly applications, to one set of the Admire plots after the whitefly had become established. Actigard 50WG and Fulfill 50WG were also applied midseason to one set of the Platinum plots. Actigard was applied weekly for four weeks beginning 4 May at 0.33 lb product/acre and increased incrementally at 0.75 oz product/acre. The Fulfill was applied in two weekly applications beginning 11 May and tank mixed with an organosilicant, Kinetic, at 0.1% v/v. The HMO’s were tank mixed with the weekly fungicide applications. Normal cultural practices were followed to control other pest and diseases. Eight weekly evaluations of whitefly adults were made beginning 8 Apr by beating one side of four plants at three locations per plot with a 9 × 13-inch pie pan painted black and coated with a 9:1 mixture of vegetable oil and liquid detergent. Immature stages were monitored 26 Apr, 11 and 24 May, and 1 Jun using one leaf removed from the sixth node of four centrally located plants in each plot. All whitefly stages were counted that appeared in a 2-cm2 ring placed once on the three terminal leaflets from each leaf collected. Plants were evaluated five times from 29 Apr to 24 May for the presence of severe TYLC symptoms. Fruit was harvested from the 20 plants per plot on 2 Jun and the number and weights of insect, disease and marketable fruit were recorded. Data were subjected to ANOVA and means were separated using LSD (P ≤ 0.05).