Population Dynamics of Adelges knucheli and its Predators in the North-Western Himalayas I. Host Phase: Gallicola
Studies on the populations of the gallicola phase of Adelges knucheli (Schneider-Orelli & Schneider) (Homoptera, Adelgidae) and its predators were carried out in the north-western Himalayas. Mortality of gallicolae occurred when hatching did not synchronise with flushing of spruce. Among biotic factors influencing mortality of gallicolae, two chamaemyiids Mesoleucopis raoi Tanas. and Leucopis sp. played a dominant role. Three lepidopterous borers indirectly affected the population by tunnelling the gall-chambers. Heavy mortality of the chamaemyiids occurrcd whenÂ there was no synchrony between hatching and maturing of pseudocones; another cause wasÂ probably the large nuinber of eggs laid on a pseudocone, which was disproportionate to the host material available. The number of gallicolae that migrated and settled on the top crown of silver fir trees was about twice that settled in the lower crown. This probably accounted for the high incidence of dead and stunted growth of top crowns of silver fir.
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