Laboratory evaluation of an azadirachtin enriched formulation (econeem 0.3%) against Helicoverpa armigera of cotton

A neem based product (Econeem 0.3%) containing azadirachtin was tested in the laboratory to mitigate the menace of Helicoverpa armigera on cotton, Azadirachtin treated food was given to 1^st, 2^nd, 3^rd, 4^th and 5^th instar larvae separately for 24 h. Subsequently, the larvae were fed on untreated cotton leaves and cumulative larval mortality until pupation was recorded. Observations on larval period, weight and length of larvae, pupal period and length, adult emergence and adult abnormalities, fecundity and female longevity were recorded. The LC₉₀ values of 1^st, 2^nd, 3^rd, 4^th and 5^th instar larvae were 0.65, 1.52, 2.17, 3.29 and 3.24 mg a.i. 1⁻¹, respectively. Azadirachtin treatment significantly affected larval length, larval weight, pupal length, pupal weight and pupal duration. Pupal deformities were also noted in the treated population. Besides, neem product affected adult emergence and fecundity of test insect. Abnormalities in adults were also evident. Adverse effects on consumption index (CI), growth rate (GR), efficiency of conversion of ingested food to body substances (ECI), approximate digestibility (AD), efficiency of conversion of digested food to body substances (ECD) in treated population were also noted.