Plant injury is caused by both nymphs and adults rasping the bud, flower and leaf tissues of the host plants, and then sucking the exuding sap. This causes distorted and discolored flowers or buds and gray or silvery, speckled areas on the leaves. Gladiolus thrips also feed on the corms in storage, causing russeted areas and lowering vigor, which retards growth and makes the flowers smaller. After successful mating, eggs are laid on plants with the young developing to maturity in about two or more weeks. The number of generations produced each year depends on the thrips species, temperature and other climatic factors.
Most species produce many generations in a season.
Females may lay fertilized or unfertilized eggs, the latter developing into males only. There are four or more nymphal instars exhibiting gradual metamorphosis. Both nymphs and adults overwinter concealed in grass stems or other plant debris with activity continuous in warmer climates. Control Measures Try to locate the source of infestation. Nursing homes, interior scapes, greenhouses, grassy areas, pool areas, etc.