The biology of fruit borer was studied under laboratory condition indicate that the metamorphosis is complete. The four development stages of life cycle viz. egg, larvae (caterpillar), pupa and adult were present. It is found in tropical and subtropical areas and the following result reveals that, the mean average eggs hatching period on day 3 after spraying was found T₄ (Untreated) <T₃ Neem Oil (0.03%) <T₁ Malathion (0.04%) <T₂ Methyl Dematon (0.02%) over all replications. Then the average larvae period of Helicoverpa armigera (Hubner) in days under lab condition were found that total average of larva period was 21.51 days March – April followed by T₄ (21.05) <T₁ (21.25) <T₃ (21.75) <T₂ (22) and the total average period was 22 April to March. The pupal stage lasted 10 days and data shows that The average period of pupa is 10 days under lab conditions followed by the treatments were T₁ (10.5) & T₃ (10.5) < T₂ (11.5) <T₄ (11.25) found. Harvest crop at bichpuri (Agra) revealed no trace of egg, larvae, or pupal were found in the field which indicated that moth already emerged and have migrated to somewhere else. During April when maximum temperature reached up to 30^o C the moth were unable to lay eggs and died within 3 days only few larvae could complete the development up to pupal stage at this temperature. The started infestation of chilli fruit borer in experiment plot from November onward maturity. The Pest population count on randomly selected 5 plants against each treatment in each replication after 7 days of 1st spray were found T₁ (10.4) <T₂ (11) <T₃ (11.6) < T₄ (14.2) after that pest population count on randomly selected 5 Plants against treatment in each replication after 10 days of 1st spray study found that,