This group contains some extremely small insects that can cause extensive plant damage. Although most of these insects are plant feeders, a few are predaceous on other insects. Thrips damage plants directly by feeding. Much of the damage caused by larvae occurs within developing leaves and flowers - this damage is very noticeable once the affected parts expand. These areas are often distorted, and flowers may not open.
Some thrips also damage the plant indirectly, by transmitting the virus that causes spotted wilt.
Some of the more important thrips of floricultural plants include the onion or tobacco thrips, the greenhouse thrips, the eastern flower thrips, and the western flower thrips. Western flower thrips. I have selected this insect as a typical example of a thrips. Their rapid life cycle and high reproductive capacity, combined with the fact that larvae, concealed within plant parts, are the only stages very susceptible to insecticides, lead to great difficulty in detecting and managing these important pests. The western flower thrips has a wide host range that includes many ornamental plants.