Seed Treatment Evaluated for Greenbug Control in Sorghum, 1994

Seed of three sorghum hybrids treated with 0, 2 or 4 oz AI of Gaucho per cwt were furnished by Gustafson, Inc. The hybrids used in the study were NC+ 271 (greenbug susceptible), DK 56 (biotype- E resistant), and Cargill 607E, (biotype-I resistant). All three hybrids were pretreated with Captan and Concept and the DK 56 was also pretreated with Apron. The seed was planted on 24 May in a modified Latin square design with three replications. Each plot was two rows wide (5 ft) and 22 ft long. The seed was planted at the rate of 5 g per row using a cone planter. On 23 Jul corn leaf aphid and greenbug populations were monitored by cutting off two plants per plot and counting the number of aphids on the plant and removing the whorl and counting the number of aphids observed as the leaves were unrolled. On 4-5 Aug, two plants were cut off at the base and visually examined to estimate greenbug numbers. Yield data were collected by machine harvesting the plots on 27 Oct.