Report of an Olive Lace Bug Infestation on Olea europaea ssp. cuspidata (Wall, ex G. Don) P. S. Green in Desa’a Natural Forest, Northern Ethiopia

Abstract

Olea europae subsp. cuspidata is widely grows in natural forests in many parts of Ethiopia. However, there is scanty information about the impact of insect pests’ infestation in the natural forests o f Ethiopia. Based on the outbreak of pest infestation report in Dessa ’a Natural Forest located in the border between Tigray and Afar national regional states of Ethiopia, field survey was conducted in November 2012. It has been observed that the nymph and adults of Plerochilia australis, attached to the underside of leaves of olea trees, were found to be responsible for yellowing and scorching of leaves that resulted in serious defoliation of tree regardless of age difference. In Esot, where the infestation first observed, nearly all trees were found infested and several dead trees were found. Similar infestation by P. australis was also observed in the leaves of Oleaeuropeae subsp europeae seedling which were introduced in recent years to Atsebi- Wemberta District of Tigray Regional Slate. The level o f insect infestation was observed to vary between the native and introduced trees and from one place to another based on climatic variables. Accordingly, more infestation were observed in the native than the exotic species and in warmer than cold weather. The lack of knowledge on the biology and ecology of P. australis  in Ethiopia limited the effort to control the impact and expansion of this pest.