Insecticide efficacy against Louisiana populations of bollworm and tobacco budworm during 2000

摘要

Bollworm (BW) and tobacco budworm (TBW) control with Tracer 4SC (0.067 !b AI/acre) or Steward 1.25SC (0.11 lb AI/acre) was compared between ground (6 GPA) and aerial (3 GPA) application methods. Four applications were applied during late Jul to early Aug on Phytogen 355 cotton. Both Tracer and Steward reduced the number of BW/TBW injured and larval infested fruiting forms and increased seedcotton yield compared to the non-treated plots. Treatments applied by ground were more effective in controlling BW and TBW compared to those applied aerially. In a second experiment, the ovi-larvicidal efficacy of selected insecticides was evaluated against native BW and TBW infestations. Ovi-larvicidal toxicity ranged from 12.5 percent (Provado 1.6SC, 0.0375 lbAI/acre) to 77.5 percent (Steward 1.25SC, 0.11 lb AI/acre). The highest levels of mortality to eggs and larvae were measured for Tracer 4SC (70 percent) (0.067 lb AI/acre), Denim 0.16 EC (75 percent) (0.01 lb AI/acre), and Steward 1.25SC (77.5 percent)(0.11 lb AI/acre).