Insect identification > Thysanoptera > Pear thrips

Pear thrips


The pear thrips (Toeniothrips inconsequens Uzel). - This insect was first discovered in the United States in the central part of California and is now found as far north as British Columbia, attacking deciduous fruit trees, particularly pears, prunes and cherries, blighting the blossoms by the abstraction of their sap. Later it was found in the Hudson River Valley in New York, and still later in Pennsylvania, Maryland and England. Recently it has been learned that the insect was first discovered in Bohemia, feeding in blossoms.

The destruction caused by this pest in California has been very great during some years. The injury is caused by the feeding of the young and adults on leaves, buds, flowers and fruit, and by laying eggs in the leaves and fruit stems and also in the small fruit.

The dark-brown-almost black-adults appear early in spring, coming out of the ground about the time the fruit buds are swelling and opening, and as soon as these have opened slightly the insects work their way into them and feed on the most delicate parts. The eggs are laid mainly in the young leaf and fruit stems and young fruit and hatch on an average after about 8 days.

The nymphs feed on the leaves and young fruit, forming a sort of "scab" on the surface of the latter, and remain on the tree for 2 or 3 weeks, though the time from the first young's appearance to the last young's disappearance may be more than 2 months.

When through feeding they fall to the ground, which they enter for a varying distance, and there, after 2 to 5 or 6 months, they transform to the last stage before the adult, having previously molted once underground. Late in the fall or winter the final molt produces the adults which remain in the ground till early spring.

This remarkable life history, quite unlike anything known for any other Thysanoptera, permits but one generation a year, with active injury during only a rather short period in the spring.