Efficacy of insecticides of different chemistries against Helicoverpa zea (Lepidoptera: Noctuidae) in transgenic Bacillus thuringiensis and conventional cotton.
Six insecticides of different chemistries were evaluated against the cotton bollworm, Helicoverpa zea (Boddie), in non-B.t. (Deltapine 'DP 5415', Deltapine 'DP 5415RR') and transgenic Bacillus thuringiensis (Berliner) (B.t.) (Deltapine 'NuCOTN 33B', Deltapine 'DP 458 B/RR') cotton. In 1998, treatments consisted of three rates each of a pyrethroid (lambda-cyhalothrin), spinosyn (spinosad), carbamate (thiodicarb), pyrrole (chlorfenapyr), oxadiazine (indoxacarb), and avermectin (emamectin benzoate) in a nonirrigated field. In 1999, treatments consisted of three rates each of lambda-cyhalothrin, spinosad, thiodicarb, and indoxacarb in an irrigated and a nonirrigated (dryland) field. The highest rate of each insecticide corresponded to normal grower-use rates. Spinosad and thiodicarb controlled H. zea in non-B.t. cotton, whereas other materials were less effective. Even though H. zea is becoming increasingly resistant to pyrethroid insecticides, lambda-cyhalothrin was highly effective in dryland B. thuringiensis cotton. Spinosad and thiodicarb were equally effective. Data indicated that reduced rates of lambda-cyhalothrin, spinosad, and thiodicarb could be used for control of H. zea in dryland B.t. cotton systems. However, reduced rates of these insecticides in a heavily irrigated B.t. cotton system did not provide adequate control.
Brickle
D S
DS
Edisto Research and Education Center, Clemson University, Blackville, SC 29817, USA.
Turnipseed
S G
SG
Sullivan
M J
MJ
D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics; D004338:Drug Combinations; D003368:Gossypium; D007300:Insect Control / Q000379:methods*; D007306:Insecticides; D018942:Macrolides; D009036:Moths; D009570:Nitriles; D010078:Oxazines; D030821:Plants, Genetically Modified; D011722:Pyrethrins; D013859:Thiocarbamates
D004338:Drug Combinations; D007306:Insecticides; D018942:Macrolides; D009570:Nitriles; D010078:Oxazines; D011722:Pyrethrins; D013859:Thiocarbamates; C401104:indoxacarb; C027971:thiodicarb; C037304:cyhalothrin; C415329:spinosad