Insect external structure
Insect internal structure
Development of insects
Relationships of insects
Insect identification > Thysanoptera > Citrus thrips
The citrus thrips (Scirtothrips citri Moult.) is a rather serious pest in California and Arizona. It feeds upon the tender stems, leaves and fruit of citrus trees and occasionally also attacks the grape, apricot and other plants. With seedling plants the leaves and buds are injured and growth is checked. The fruit is injured by scars and scabs caused by the feeding and greatly reduced in value, and some drop to the ground.
The adult is one of the smallest of the Thysanoptera, varying from onefiftieth to one-twentieth of an inch in length, and is orange-yellow in color. The young appear in April and May and gather on the leaves and fruit where they remain until the midsummer hardening of these parts leads most of them to leave for various other food plants until August and September when they return to the citrus trees again and lay their eggs in the leaves and stems of the plant. These winter over and hatch the following spring.
Following the production of adults from the hatching and development of these eggs, there may be six to eight generations during the season and all stages may be present at once an a tree as late as December, though these die with colder weather, leaving only the eggs to hatch in the spring. The last stage before the adult, during which the insect is quiet, is passed in crevices of the trunks or in rubbish under the trees, but not in the ground.