Order
THYSANOPTERA(Greek, thysanos = fringe; pteron = wing)
Common Names
thrips
Description
The distinguishing characteristic of thrips is the possession of two pairs of fringed wings. Thrips are small insects, 0.5-15 mm long. Compound eyes are well developed and three simple eyes (ocelli) may be present in winged forms. The antennae are composed of short straight segments (filiform). The mandibles and mouthparts are highly modified for rasping and sucking. The winged forms are capable of weak flight, but can cover large distances when assisted by the wind.
Life Cycle
Females lay eggs directly into plant tissues or crevices in vegetation. The emerging juveniles resembles the adults (nymphs) but are wingless. The nymphs mature by successive moults but some of these stages may involve considerable resting when large amounts of internal tissue alteration takes place. Some species of thrips inhabit litter while others manufacture galls in which they have complete protection while feeding. Females lay their eggs in a slit in plant tissue. The egg hatches and the developing nymph causes the plant tissues to swell and form a gall. In the centre of the gall is a cavity where the nymph continues to feed and develop.
Food
Thrips feed on plant sap obtained by rasping at the vegetation surface and sucking up the resulting fluid. Litter inhabiting thrips consume fungi.
Importance
Thrips are of immense importance as pests in horticulture. Some crops subject to thrips damage are onions, tobacco, pears, apples, bananas and citrus, but there are many more. Numerous flowering plants are also attacked.