Diversity and occurrence of defoliators and stem borers associated with Eucalyptus camaldulensis, Dalbergia sissoo, and Vachellia nilotica in Chichawatni Plantation, Punjab, Pakistan

Abstract

Insect pest outbreaks pose a significant threat to productivity and sustainability of plantation forests in Pakistan, particularly in the context of the country’s severe forest deficit. Current study provides the first comprehensive assessment of defoliator and stem borer complexes associated with three cornerstone plantation species, Eucalyptus, Shisham and Babul in the Chichawatni irrigated plantation of Punjab, Pakistan. A systematic survey employing stratified random sampling was conducted over a complete annual cycle. Insect collection were made using visual observation, hand-picking and beating sheet methods for defoliators, while stem borers were detected through symptom-based examination of exit holes, frass, gum exudation and bark dissection. A total of 3158 individual pest from 26 species were recorded, with the defoliators constituting 59.9% and stem borers 40.1% of the assemblage. Babul hosted the highest pest load and exhibited most severe defoliation along with the poorest tree health score. Shisham predominantly affected by stem borers while Eucalyptus showed more balanced pest complex with significant pressure from both Chrysophtharata bimaculata and Phoacantha semipunctata. Statistical analysis revealed strong positive correlation between pest abundance and defoliation and strong negative correlation between defoliation and tree health. One way ANOVA showed significant difference in defoliation among species. Current study identifies key pest species requiring prioritized management and establishes baseline data for monitoring pest population dynamics in Chichawatni plantation. The findings support development of species-specific integrated pest management strategies, with critical implication for sustaining plantation productivity in one of Pakistan’s largest man-made forest.