Thrips Control; Effect on Plant Growth, 1986

Abstract

Abstract This test was conducted to compare insecticides applied in furrow for thrips control and to determine the effects on plant growth characteristics. The plots were 4 rows × 20 ft long with 4 replicates in a randomized complete block design. The soil type was Austin clay. Treatments were Temik 15G at 0.25 and 0.5 lb (AI)/acre, Counter 15G at 1.0 and 2.0 lb (AI)/acre, and Furadan 10G on corn cob grit (CCG) at 0.5 and 1.0 lb (AI)/acre. These treatments were applied in furrow at planting with a John Deere Flex 71 planter on 13 May. Plants from the outside rows were pulled and beaten on hardware screen over a white pan and thrips adults and nymphs counted. Twelve consecutive plants from each outside row were collected and thrips were counted on 27 May, 6 Jun, and 10 Jun. Ten consecutive 28-day-old plants from the center 2 rows were pulled on 19 and 20 May, and plant growth data were determined by dissecting the tap root at the cotyledon leaf node and leaves at the petiole. Leaves, stems, and roots were then weighed separately. The number of plants that were squaring was determined. Later in the season, earliness was measured by counting the number of bolls on 0.02-acre subplots in each center row. Total yield was obtained by stripping the center 2 rows with a brush stripper on 18 Sep.