Exploring natural resources for sustainable management of ecosystems future challenges for control and management of Xyleborus fornicatus eichh. (Coleoptera Scolytidae), the shot-hole borer of tea in Sri Lanka

Abstract

In view of the highly diverse genetic base of the seedling tea plants, though cultivated as a monocrop,along with shade trees and surrounding forests, provided a reasonably stable ecosystem then. Withthe introduction of high yielding vegetatively propagated tea during 1950's, a significant change in thedistribution and population densities of pests has been taken place. Shot-hole borer is one such pestand since then it has become the most serious and damaging pest of tea in Sri Lanka. Control hasbeen a difficult task as a result of its' wide distribution from near sea level up to 1500m amsl and theconcealed habit virtually protected from parasites and predators. Biological control usingentomopathogenic fungus, Beauvaria bassiana Vuillemin (Balsomo ) is being viewed as anenvironmentally friendly alternative to chemical control in the light of growing concern on the usage of pesticides and since oflate, the detection of pesticide residues in made tea. Preliminary investigationswere carried out with a view to find out a suitable local strain/s of the fungus for use against this pest.

Laboratory studies have shown that strains of this fungus isolated from a tea garden in Talawakelle(Nuwera Eliya District) and a home garden in Welimada (Badulla District) are highly pathogenic toshot-hole borer imparting more than 90% mortality. A potential exists for using the locally availablenatural resources like entomopathogenic fungi for the management of key pests in a compatible andecologically acceptable manner. This forms the basis for Integrated Pest Management (lPM) approachof key pests. These efforts will promote and ensure the sustainable development of the tea ccosyst;m.