Coherent Identifier About this item: 20.500.12592/57x669

A Note on the Chilgoza (Pinus Gerardiana) Bark-Boring Beetles of Zhob Baluchistan




The number of dead trees still standing in the forest would in themselves prove this to be the case but better evidence of the truth of the supposition is to be found in an examination of the insect galleries in the sap wood. [...] The larger of the pair a species of Polygraphus is the most serious pest the trees have to fear and the chief cause of their death whilst the other is a species of Phleosinus and is to be found in company with the Polygraphus in both trunk and branches. [...] The grubs on hatching tunnel away from the egg gallery in a direction which is more or less at right angles to it in the case of the first laid and therefore the lowest eggs the direction however trending upwards (or downwards when the egg gallery is carried downwards) in the case of the eggs laid higher up the gallery. [...] The bark on the portion of the side infested by the beetles will die and the vitality of the tree will be lowered in consequence. [...] The life history of the Polygraphus the most dangerous of the three is now practically known with the exception of the important point about the number of generations and the same remark applies to the Pityogenes.


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