ABSTRACT
Profenofos, thiodicarb and amitraz were applied aerially onto pots of greenhouse-grown cotton plants placed into position with field-planted cotton at two active ingredient (AI) rates (0.14 and 0.28 kg per ha) using a spray rate of 46.8 L per ha. Tobacco budworm moths (TBW), Heliothis virescens (F.) were released into cages containing cotton plants sprayed with insecticides. None of the insecticides nor AI rates significantly influenced TBW adult mortality (P > 0.05), and there was no significant interaction between AI rate and insecticides (P > 0.05). Profenofos, thiodicarb, amitraz and methyl parathion were applied at five AI rates (0.14, 0.28, 0.56, 0.84 and 1.12 kg per ha) in a spray table onto greenhouse-grown cotton plants. Insecticides significantly influenced mortality of TBW moths (P < 0.001), and there was a highly significant interaction (P < 0.001) between insecticides and AI rate. Tobacco budworm mortality increased with AI rate with profenofos. Active ingredient rate in thiodicarb did not significantly influence TBW mortality. Neither methyl parathion nor amitraz showed any consistent TBW mortality response to AI rate. Amitraz significantly increased the number of spermatophores per female (avg = 1.19) in TBW moths when compared with the control (avg = 0.70). The numbers of spermatophores per female in treatments with thiodicarb (avg = 0.36), methyl parathion (avg = 0.35) and profenofos (avg = 0.13) were not significantly different from one another, but these values were significantly less when compared with the control. Data suggest that amitraz significantly increased the number of spermatophores per female in H. virescens and that profenofos may be applied as an adulticide at an AI rate of 1. 12 kg per ha to suppress adult TBW on cotton. Methyl parathion also caused significant mortality of TBW moths at lower AI rates when compared with profenofos.
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