Scandinavian Journal of Forest Research (2002) 17, 150-157

Carolyn Glynn and Åke Lindelöw (2002)
Defoliation by the needle-shortening pine gall midge, Thecodiplosis brachyntera, on pines in central Sweden
Scandinavian Journal of Forest Research 17 (2), 150-157
Abstract: An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera, occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta, however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation.
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Research topic(s) for pests/diseases/weeds:
population dynamics/ epidemiology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Thecodiplosis brachyntera	Pine (Pinus)	Sweden