Control of Silverleaf Whitefly and Tomato Pinworm on Staked Tomato with Chemical and Biological Insecticides, Spring 1994

Abstract

Abstract Beds (32 inch width) were prepared in sandy soil on six foot centers, fumigated with a 67/33% mixture of methyl bromide and chloropicrin applied at 220 lbs/acre, fertilized with a bottom mix of 800 lbs/acre of 5-16-8 and a top mix of 500 lbs of 19-0-30 and mulched with whiteface polyethylene film. Greenhouse grown tomato seedlings were transplanted 18 inches apart on 1 Mar 1994 into single rows and watered by subsurface seepage irrigation. Plants were sprayed weekly with 3.0 lb/acre Kocide DF plus 1.0 lb/acre Maneb 80W rotated with Bravo 720 applied at 32 oz/acre. Standard cultural practices of pruning and staking were followed. There were 12 rows 240 foot long divided into 4 replicated blocks of 3 rows each. Each block consisted of 10 treatments assigned in a completely randomized design. An adjuvant, ASPA 80, was added to each spray mixture at the rate of 0.06% v/v except for RH-0345 to which Latron-B-1956 was added at 0.06% v/v. Plants were sprayed weekly except for Biobit alone which was sprayed twice a week at 0.5 lb product/acre. Applications were made with a tractor-drawn hydraulic boom sprayer using a diaphragm pump at 200 psi through two drop lines per row fitted with Albuz@ ATR Yellow nozzles. Spray treatments commenced 29 Mar and continued through 10 May for a total of 7 weeks. Initial spray volume was 46 gal/acre increasing to 65 gal/acre on 5 April and finally to 83 gal/acre 3 May corresponding to the increases in number of nozzles from 2 to 3 to 4 per drop respectively. Plants were evaluated weekly for the presence of whitefly adults, eggs, nymphs, pupae, and parasitized pupae. Relative estimates of adult whitefly numbers were made by striking a black, 9.5” × 13” pie pan coated with an oil/detergent mixture against three plants from each row in every plot and recording the number of adult whiteflies caught. Egg populations were estimated from randomly sampled first expanded trifoliates, one per row (3 per plot). Eggs in 4 cm2 of leaflet were counted with a stereoscopic microscope by placing a 1 cm2 template twice on each side of the midvein. Nymphs were counted in the same way except that the trifoliate sampled came from the 5th, 6th or 7th node from the top. All plants were inspected weekly for symptoms of tomato mottle geminivirus (TMoV), the presence of which was confirmed by nuclear inclusion analysis. On 19 May, all fruit of marketable size was harvested from the best 10 plants per plot. Fruit was culled based on damage from tomato pinworm, other insects, or non-insect causes. Marketable tomatoes were sized to USDA standards on a commercial grading table.