Thrips of Flowering bulbs

Disease Information



Several thrips species, including gladiolus thrips (Taeniothrips simplex), onion thrips (Thripstabaci) and flower thrips (Frankliniellatritici) are pests of various flowering bulbs. Adult thrips are slender, tan to dark brown in color and about 1/20 to 1/16 inch in length with fringed wings. They tend to be found in protected areas of the plant.

Symptoms and damage

Both adults and nymphs (immature insect stage resembling the adult, but smaller) feed by scraping surface cells to suck plant sap. When they feed on flower buds, the flowers may die without opening. With light infestation, their feeding causes leaves to have brown or silvery speckles or streaks. With severe infestations, leaves and flowers are stunted and distorted and may turn brown and die.


Several naturally occurring enemies feed on thrips, including green lacewings and ladybird beetles. To avoid killing these beneficial insects, which naturally reduce thrips populations, insecticides should be avoided as much as possible. Bright blue or yellow sticky traps will provide some protection from thrips. Paint cardboard or wooden boards and then coat with petroleum jelly. Attach them to stakes and place near the flowering bulbs. The adults are attracted to the yellow or blue and get caught in the petroleum jelly.

Insecticidal soap can be used, but thorough coverage is required. Where absolutely necessary for very valuable plants, spray with spinosad or acephate when damage is first noticed. Be sure that the particular plant species that you want to spray is listed on the label



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