A study on pesticidal potential of plant extract of a native species, Boenninghausenia albiflora (Hook) to restrain insect pests of forestry in northwest Himalayas

Forestry plantations in the northwest Himalayas are increasingly threatened by insect pests such as Agrotis ipsilon and Plecoptera reflexa, which cause severe defoliation and economic losses. The present study evaluated the pesticidal potential of leaf extracts of the native plant Boenninghausenia albiflora (Hook) against these two major forest insect pests under laboratory conditions. Leaf extracts were prepared using methanol, acetone and ethyl acetate and their insecticidal efficacy was assessed using the leaf-dip bioassay method. Among the tested solvents, the methanolic extract showed the highest extraction yield (18.58%) and insecticidal activity, causing 60.00 per cent mortality in P reflexa and 56.66 per cent mortality in A ipsilon at 1 per cent concentration after 72 h . Further bioassay of the methanolic extract at graded concentrations (0.25-1%) demonstrated a dose-dependent increase in larval mortality. The LC₅₀(%) values ranged from 0.81 to 0.89 per cent for P reflexa and 0.86 to 0.96 per cent for A ipsilon. GC-MS analysis revealed that the extract was rich in bioactive terpenoids, with α-pinene (16.56%),(+)-sylvestrene (16.27%), β-pinene (14.82%) and carvone (6.51%) as the major constituents. These compounds are known to possess insecticidal, repellent and neurotoxic effects against insect pests. The findings demonstrate that B albiflora leaf extract possesses significant insecticidal activity and may serve as a promising eco-friendly botanical alternative for the management of forest insect pests in the northwest Himalayan region.