Rate and Formulations Test for Early-Season Control, 1988

Abstract

Abstract New formulations of Thimet (AC513484 20 G) and Counter (AC301467 20 G) were evaluated at rates of 0.75 and 1.0 lb (AI)/acre and compared with the standard formulations and with Temik at the same rates. Seed treated with Orthene 80 S at 8 oz/cwt served as a control. Terraclor Super X (TSX) at 10 lb (form.)/acre was applied with all treatments at planting. Test plots of 4 rows (40-inch spacing) by 65 ft were replicated 4 times in a randomized complete block design. Cotton was planted on 28 Apr on a Commerce silt loam soil at the Northeast Research Station, St. Joseph, La., and fertilized with 70 lb nitrogen/acre. Test treatments were applied in furrow with a John Deere 7300 series planter equipped with granular applicator split boxes. Major and secondary pest treatments were initiated in late June and maintained as needed through August. Treatment efficacy for thrips and aphids was measured by washing insects from 5 seedling cotton plants/plot onto 300-mesh screens, backwashing them onto lined filter paper (7 cm), and counting them with the aid of a binocular dissecting microscope. Collections and observations on these pests were made 13 and 27 May. Data on insect populations are reported as the means of these observations. Stand data were recorded by counting all plants on the center 2 rows of all plots 23 May and 17 Jun. Plant population data reported are the means for these 2 observations. Leaf area data were recorded on 27 May by randomly selecting 5 plants/plot and measuring all leaves with a LI-COR leaf area machine. Plant height data for 10 plants randomly selected from each plot were recorded 30 May. Yield was estimated by harvesting all 4 rows of each plot with a mechanical harvester 9 Sep.