ABSTRACT
Eucalyptus plantations and nurseries in several localities in Tamil Nadu, Karnataka, and Andhra Pradesh have been invaded in recent years by Leptocybe invasa, a tiny hymenoptera wasp from Australia, inducing galls on shoot terminals, on petioles and midribs, and on saplings and trees.12 Successful establishment has occurred on clones of Eucalyptus camaldulensis (Figure 11.2); being a long-rotation crop, impact of galls on productivity is considerable.12 Because of the importance of trees as key species in forest ecosystems, the impact of invasive species on trees is more obvious. Extensive plantations using such clones of E. camaldulensis facilitate spread of Leptocybe in states like Tamil Nadu and
Andhra Pradesh, with continuous enlargement of the infected area. Variations of incidence of galls and intensity of injury and damage exist among these clones.12 Accidental transportation of infested seedlings into uninfected areas for plantation purposes increased the likelihood of spread of Leptocybe to new areas. The coconut eriophyid mite Aceria guerreronis, introduced in the 1990s, is still causing serious damage to coconut, not to mention the threat of invasion by new pests like the Brontispa beetle.13
