These tiny winged insects feed on leaves, buds and flowers. They suck the sap and cause white or silvery patches or areas where they have fed. Thrips can cause problems while the plant is growing or during storage. Bulbs and corms stored can be dusted with insecticide and sprayed when in growth.
On this Gladiolus the stripes look like thrips attack. Thrips are very dangerous and look like very minute black flies. Their attack is particularly evident in Gladiolus flowers (like silver patches). One thrips species, Frankliniella occidentalis, is much feared as it is extremely efficient in spreading virus among nursery stock. Photo by Jennifer Hildebrand