Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/31/2012
Publication Date: 5/1/2012
Citation: Luttrell, R.G., Jackson, R.E., Allen, K.C. 2012. Insecticide treated and untreated Bt and conventional cottons under high insect pressure in large field cages. National Cotton Council Beltwide Cotton Conference. In: Proceedings of the Beltwide Cotton Conference January 306, 2012 Orlando, FL pp. 1126.
Interpretive Summary: Commercial Bt and non-Bt cottons were compared to new cotton lines (ARK48 and MD25) being developed by the University of Arkansas and the USDA ARS in Stoneville, Mississippi. These cottons were grown under large (1/8 acre) field cages and exposed to high densities of bollworm and tobacco budworm moths. All cottons were then left unsprayed, sprayed with Coragen, a long residual and expensive insecticide, or sprayed with Karate, a standard and affordable pyrethroid insecticide. Plants from each cotton under the different insect management systems were mapped for insect damage and fruit retention during the growing season. Yield was determined by box mapping plants at harvest.
Technical Abstract: Early maturing Bt cottons (DP0912 and PHY375), early maturing conventional cottons (ARK48 and DP121), a full season Bt cotton (DP1048) and full season conventional cottons (MD25 and DP174) were grown in large field cages and exposed to high densities of bollworm and tobacco budworm moths over a three week period. Following detection of eggs on the plants, the different varieties were sprayed with chlorantraniliprole or lambda-cyhalothrin or left untreated. The experiment with all seven cotton varieties managed under the three different insect protection treatments was replicated in three large field cages. Plots were monitored for insect damage, and plants were mapped for retention of fruiting structures post-treatment with insecticides. Yield was measured by box mapping procedures to generate cumulative yield relative to fruiting site or time of fruit initiation.