Biological and in vitro effects of Neem (Azadirachta indica) extract on second and third instar larvae of Spodoptera litura

Spodoptera litura is a major threat to agricultural crops all over the world including Pakistan. It has developed resistance to several chemicals, especially synthetic insecticides. Plant based chemicals like extracts may serve as suitable and alternative biocontrol methods for pests in the future. The current study was conducted to determine the biology of S. litura on cabbage and the effects of two botanicals i.e. Azadirachta indica and Eucalyptus globulus against 2nd and 3rd instar larvae in controlled conditions. The incubation period of pest was 3-4 days. The average mean developmental period of 1st, 2nd, 3rd, 4th, and 5th larval instar was 2.44±0.71, 2.32±0.74, 3.43±0.68, 2.76±0.80, and 2.40±0.79 days, respectively. The pre-ovipositional, and ovipositional period of females was 2.04-3.58 and 2.89-5.71 days respectively. The total life cycle of pests was 30.83-38.79 days. Significantly higher mortality of 2nd and 3rd instar larvae was recorded in A. indica. The percentage of mortality increased with an increase in treatment time.