General Information

Common names: Thrips
Thysanoptera:Thripidae

Important species

Bean thrips (Caliothrips fasciatus)
Onion thrips (Thrips tabaci)
Rice thrips (Stenchaetothrips biformis)
Thrips (Ceratothripoides claratris)
Western flower thrips (Frankliniella occidentalis; F. williamsi)

Host plants

Most agricultural crops

Distribution

Worldwide

Damage

Thrips have rasping-sucking mouthparts and feed by rasping the surface of the rapidly growing tissues of the leaves and sucking up the released plant fluid. Thrips cause tiny scars on leaves and fruit, called stippling, which can cause stunted growth. Damaged leaves may become papery and distorted. Infested terminals lose their color, rolled, and drop leaves prematurely.

In beans, thrips causes feeding damage on flowers and young pods.

In onions, they feed under the leaf folds and in the protected inner leaves near the bulb. Leaf scarring is a serious problem on green onions. When the population level is high, thrips can also be found feeding on exposed leaf surfaces. Both adults and nymphs cause damage. When foliage is severely damaged, the entire field takes on a silvery appearance.

In rice, the feeding damage causes tearing of the plant tissues. The damaged leaves are having silvery streaks or yellowish patches and curled from the margin to the middle. Infested panicle causes unfilled grains.

Thrips are vectors of the tomato spotted leaf virus.

Description

The egg is very tiny and is impossible to see. A single egg is 0.25 mm long and 0.1 mm wide. It is white when freshly laid and turns pale yellow toward maturation.

The nymph is elongated, elliptical, slender, and is pale-yellow in color. It is very small from 0.5-1.2 mm in size. Its eyes have darker coloration and are easy to see. Immature thrips do not have wings.

The pupa appears as an intermediate form between the nymph and the adult. It has short wing buds that are not functional. At this stage, they do not do any damage to the plant.

The adult has a slender small body, yellowish to dark-brown in color, and is cigar-shaped. It is 1-2 mm long with a well-pronounced 5-8 segmented antennae. It can exist in two forms, winged or wingless. The winged form has two pairs of elongated narrow wings which are fringed with long hairs.

Female thrips can reproduce both sexually and asexually.