Investigation on the Decline of Balanites aegyptiaca (Heglig) tree Associated with the Cerambycid Beetle, Macrotoma palmata, in the Blue Nile area � Middle Region of Sudan

Abstract

This study was done to assess the impact of the longhorn beetle, Macrotoma palmata,on Balanites aegyptiaca in the Sudan. The research was to investigate the phenomenon of the decline of the wood of the tree by the wood boring beetle. A total of 14 plots were randomly selected from Khour Abuseif forest, regenerated by B. aegyptiaca wood tree species. Each selected plot had a square shape, with an area of � hectare. In each selected plot, trees were counted and grouped into 2 different categories: sound trees and infested ones. For further recognition of the infested trees, dissection of the suspected branches was done to ensure the presence of one or all developmental stages of the pest. Mean frequency of infestation in the trees was determined in each selected plot by counting the infested ones in each chosen plot. Approximately, the overall mean frequency of infestation was 24% from the whole computed trees. In each selected plot, different growth parameters were measured in sound trees and compared with those of infested ones. High significant reductions, in the parameters of the infested trees, were recorded. The mean reductions in diameter at breast height (dbh), height (h), volume (v) and mean annual increment (m.a.i) of the infested trees in reference to sound ones was15.62%, 17.90%, 41.53% and 40.6% respectively.