Improper pruning practices increase the intensity of infestation of Indarbela sp. (Cossidae:Lepidoptera) in Dalbergia sissoo Roxb. plantation

The present study investigated the relationship between wounds on Dalbergia sissoo Roxb. trees and infestation by Indarbela sp. Field observations revealed that improperly pruned trees exhibited a greater number of wounds, primarily caused by incorrect pruning practices, which served as favourable sites for caterpillar shelter, oviposition and stem boring. Correlation analysis demonstrated a strong positive association between wound incidence and the number of active holes, with coefficients of r = 0.836 at improperly pruned (T1) site and r = 0.752 at non-pruned (T2) site. Regression analysis indicated that wounds accounted for 69.9 % and 62.6 % of infestation variation in improperly pruned and non-pruned site, respectively. Comparative analysis using t-test confirmed significantly higher infestation levels in improperly pruned trees (mean = 5.5 active holes/tree) than in non-pruned trees (mean = 1.5 active holes/tree; t₀.₀₅ = 2.024, p = 1.30 × 10-6). The study highlights that improper pruning practices exacerbate Indarbela sp. infestation by creating suitable microhabitats for caterpillar development, leading to cyclical damage and increased active holes. Adoption of proper pruning techniques are essential to reduce infestation and maintain the health of D. sissoo plantations.