No abstract

The efficacy of various preparations of neem (Azadirachta indica A. Juss) (NCE1) and cells suspension extracts (NCE2) was evaluated against three cotton insects including pink bollworm (Pectinophora gossypiella), bollworm (Helicoverpa armigera) and leafworm (Spodoptera litura). The cotton leaves and medium size excised bolls were sprayed with different dilutions of NCE1 and NCE2 and 3rd instar larvae were incubated. The dilutions T1 (1:10 v/v Extract: D.H 2 O) and T2 (1:100 v/v Extract: D.H 2 O) of both NCE1 and NCE2 showed highly significant results as almost 100% mortality was recorded after 2 to 3 days hours of larvae incubation. The larvae showed a repellent behavior, decrease in weight, and negligible leaf area damage. The preparation T3 (1:1000 v/v Extract: D.H 2 O) showed 76 to 84% mortality, T4 (1:10000 v/v Extract: D.H 2 O) 28 to 72%, and T5 (1:10000 v/v Extract: D.H 2 O) 12 to 40% mortality after the 5th day of incubation. The larvae also showed repellent to non repellent behavior, slow to moderate feeding activity with gradual increase of leaf area damage as extract preparations were diluted from T1 to T3. The control showed 96 to 100% survival of all the three insect species with active feeding activity, increase in insect weight and more than 50% leaf area damage after 2nd day of incubation. In conclusion, the extracts of callus and cell suspensions of neem have insecticidal potential that showed significant mortality response against three bioassayed insects.