Control of Adult Sweetpotato Whitefly (SPWF) and Tomato Mottle Geminivirus (TMOV) Transmission on Staked Tomato, Spring, 1992

Abstract

Abstract Raised beds 3 ft wide on 6 ft centers were fertilized with a bottom mix of 508 lbs/acre of 5-16-8 NPK and a top mix of 952 lbs/acre 19-0-30, fumigated with Vapam (37% metham-sodium) at the rate of 40 gal/acre, and covered immediately with black polyethylene 3 weeks prior to setting transplants at 20 inch spacing on 23 Mar. Plots were inoculated with TMoV by transplanting 2 infected plants into the center of each middle row. Plants were staked, tied and pruned of suckers 3 times and weekly maintenance sprays of Manzate 200 (1.5 lb/acre), Tri-basic Copper (3 lb/acre), Bravo (2 pts/acre), and Dipel (1 lb/acre), were applied to control diseases and lepidopterous pests. Experimental design was a randomized complete block with 12 treatments and 4 replications. Plots were 26 ft long, 3 rows wide, separated at either end by a 4 ft buffer, and oriented 6 across and 2 deep in blocks running across the field from north to south. No significant block effects were observed. Bay NTN-33893 was applied only once with planting water as a drench. Weekly foliar applications began 24 Apr using a 3-row tractor-drawn sprayer fitted with 4 drop nozzles per row (3 sprays), or 6 drop nozzles per row (4 sprays) delivering 63.7 or 95.5 gpa respectively. Nozzles were equipped with Albuz ATR Red ceramic tips having an average output of 0.61 gal/min each at the 200 psi operating pressure. Mixture concentrations were adjusted to deliver the same amount of AI for each treatment throughout the trial. All water used for applications came from the same source and alkalinity was adjusted by adding 0.18 ml of concentrated H2S04 per gallon prior to adding trial material. The surfactant Triton B1956 was added to the tank mix of Azatin at the rate of 20 oz/100 gal. Adult SPWF were sampled with yellow sticky cards measuring 4 × 4 cm stapled back-to-back on a garden stake and placed 20 cm above soil level with card faces perpendicular to the row in a vertical plane in the center of the center row in each subplot for 24 h beginning 24 h post-treatment. Additional adult counts were made 24 h after applications by striking 5 randomly selected plants per subplot over a 31 × 20 cm teflonlined bake pan coated with a thin layer of vegetable oil and dish detergent, 16:1. Plots were inspected for TMoV and flagged a different color by date on a weekly basis for the duration of the trial.