Because the larvae feed on the foliage, they may add to the injury caused by adults. Strong spines on the 9th and 10th abdominal segments are used to penetrate the soil and mold a pupal cell. In the fall, the insects pupate within the cells and remain in the soil until the following spring. After emergence, adults migrate to the expanding buds and begin to feed. There is apparently one generation per year, adults appearing in late April to early May, and larval feeding finished by early June.
Leaves damaged by the pear thrips are dwarfed, mottled yellow to green-brown, and distorted.
This causes the tree to have a thin crown, and the effect resembles late frost damage. Blister-like scars develop along the veins and petioles of the foliage. Moderately damaged foliage can place the trees under some stress and possibly cause premature leaf drop in early fall. Severely damaged foliage could result in early spring defoliation followed by refoliation in June or July. The importance of these natural enemies is not known.