Hosts: Maple, birch, beech, ash, and cherry
Evidence: Foliage that has been severely injured by pear thrips appears distorted, tattered or stunted, and may resemble foliage damaged by late frost or strong winds (a). Close examination of the midvein and petiole may reveal swollen blister-like scars where egg-laying occurred.
Life Cycle: There is one generation a year. Insects spend the winter in the ground as pupae, and adults emerge in early spring to feed on opening vegetation and flower buds (b). Eggs are laid in the midvein or in petioles. The emerging larvae, which are pale white and translucent, feed on foliage until early June, then drop to the soil to pupate.
Management: Control of pear thrips is difficult because adults emerge and enter developing buds before trees leaf out. The damage done by thrips takes place over a short time span, and insects are concealed in buds for much of that time. Results of research on the effects of entomopathogenic fungi on pear thrips populations may provide new control options.
Similar Species: A similar species occurs on basswood. Larger predacious thrips may also occur on all of those hosts, where they feed on plant-feeding thrips
Figure a: Ronald S. Kelley, Vermont Department of Forests, Parks and Recreation, Morrisville, VT.
Figure b: E. Bradford Walker, Vermont Department of Forests, Parks and Recreation, Waterbury, VT
Johnson, W.T. and Lyon, H.H. 1991. Insects That Feed on Trees and Shrubs. 2nd edition. Cornell University Press. p 432.