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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
By Dewwanthi Karunarathna | January 18, 2008
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. With the introduction of high yielding vegetatively propagated tea during 1950’s, a significant change in the distribution and population densities of pests has been taken place. Shot-hole borer is one such pest and since then it has become the most serious and damaging pest of tea in Sri Lanka. Control has been a difficult task as a result of its’ wide distribution from near sea level up to 1500m amsl and the concealed habit virtually protected from parasites and predators. Biological control using entomopathogenic fungus, Beauvaria bassiana Vuillemin (Balsomo) is being viewed as an environmentally friendly alternative to chemical control in the light of growing concern on the usage of pesticides and since of late, the detection of pesticide residues in made tea. Preliminary investigations were 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 to shot-hole borer imparting more than 90% mortality. A potential exists for using the locally available natural resources like entomopathogenic fungi for the management of key pests in a compatible and ecologically acceptable manner. This forms the basis for Integrated Pest Management (IPM) approach of key pests. These efforts will promote and ensure the sustainable development of the tea ecosystem.
R S Walgama, P Senanayake and C De Seram
Division of Entomology, Tea Research Institute, Talawakelle, Sri Lanka.
Topics: symposium 2006 |