Acute, sublethal, and combination effects of azadirachtin and Bacillus thuringiensis on the cotton bollworm, Helicoverpa armigera.
The cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a polyphagous and cosmopolitan insect pest that causes damage to various plants. In this study, the lethal and sublethal effects of azadirachtin and Bacillus thuringiensis Berliner sub sp . kurstaki (Bacillales: Bacillaceae) were evaluated on third instar H. armigera under laboratory conditions. The LC50 values of azadirachtin and Bt were 12.95 and 96.8 µg a.i./mL, respectively. A total mortality of 56.7% was caused on third instar larvae when LC20 values of the insecticides were applied in combination with each other. The LT50 values of azadirachtin and Bt were 4.8 and 3.6 days, respectively. The results of the sublethal study showed that the application of LC30 value of azadirachtin and Bt reduced the larval and pupal weight and increased larval and pupal duration of H. armigera. The longevity and fecundity of female adults were affected significantly by the insecticides. Female fecundity was reduced by the treatments, respectively. The lowest adult emergence ratio and pupation ratio were observed in the azadirachtin treatment. The results indicated that both insecticides have high potential for controlling of the pest.
Department of Plant Protection, College of Agriculture, University of Maragheh, Maragheh, 55181-83111, Iran za.abedi88@yahoo.com.
Zahra
Z
Abedi
Department of Plant Protection, College of Agriculture, University of Maragheh, Maragheh, 55181-83111, Iran saber@maragheh.ac.ir.
Moosa
M
Saber
Department of Plant Protection, College of Agriculture, University of Maragheh, Maragheh, 55181-83111, Iran svojoudi@yahoo.com.
Samad
S
Vojoudi
Department of Plant Protection, College of Agriculture, University of Maragheh, Maragheh, 55181-83111, Iran mahdaviparchin_vahid@yahoo.com.
Vahid
V
Mahdavi
Department of Plant Protection, College of Agriculture, University of Maragheh, Maragheh, 55181-83111, Iran eparsaeyan@yahoo.com.
Ehsan
E
Parsaeyan
D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry; D005260:Female; D007300:Insect Control; D007306:Insecticides; D007814:Larva; D036701:Limonins; D008297:Male; D009036:Moths / Q000254:growth & development; D010572:Pest Control, Biological; D011679:Pupa
D007306:Insecticides; D036701:Limonins; C010329:azadirachtin
bioassay; biorational insecticides chemical control; life table