Insecticide Treated and Untreated Bt and Conventional Cottons Under High Insect Pressure in Large Field Cages

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 weeks 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 cages.   Plots were monitored for insect damage, and plants were mapped for retention of fruiting structure post-treatment with insecticides.    Yield was measured by box mapping procedures to generate cumulative yield relative to fruiting site or time of fruit initiation.