Effect of field sprayed methanolic extracts of plants on some biological traits of spotted bollworm, Earias vittella (Fab.) of cotton

摘要

Methanolic extracts of neem (Azadirachta indica], bakain [Melia azedarach) and karanj [Pongamia pinnata) seeds and ginger (Zingiber officinale) rhizomes were sprayed on cotton field (variety H 1117) at Research Farm, CCS Haryana Agricultural University, Hisar during 2005-2006. These extracts were tested at 2.5, 5.0 and 7.5 per cent to evaluate their effects on biological traits and consumption utilization indices of larvae of spotted bollworm, Earias vittella (Fab.) of cotton. A total of five sprayswere applied at 8 days interval and after 24 h of third spray, young to medium sized bolls were used to see their effects on post embryonic development of spotted bollworm. Consumption utilization studies were conducted with 7 day old larvae. The experiment at data revealed that 5.0 and 7.5 per cent neem, bakain and karanj adversely affected biological traits like survival (59-72%), duration (9.7- 13.5 days) and weight (48.09-60.34 mg) of larvae; pupal duration (9.9-11.70 days) and weight (40.65-46.07 mg); adult emergence (61.40-71.30%) and fecundity (54.70-68.07 eggs/female) and consumption utilization indices (CI, GR, AD, ECD and ECI) of the pest. Sex ratio remained unaffected. Highest concentration (7.5%) of these extracts were as effective as nimbecidine (5ml/l), a commercial neem formulation. Methanolic extract of ginger at 7.5 per cent was found ineffective against the bollworm.