Insecta, Thysanoptera, Thripidae .
Description, Biology, Life Cycle, Damage, Common Names, Images
- Host plants: peas, field beans, broad beans, beans, cultivated and wild legumes (including lucerne), which serve as feeding plants for the adults, and various other plants such as mustard (Sinapis arvensis), poppy (Papaver rhoeas) and viper's bugloss (Echium plantagineum).
- Adult: the insect flights commence in May. The main flight period is in June. They infest fields, especially in heavy, stormy weather, attracted by the pea flowers. The females lay eggs singly in the tissue of stamens but also in the young leaves, when there are no flowers. The average fertility of a female is 40 eggs.
- Egg: embryonic development lasts 5 to 10 days.
- Nymph: it feeds immediately on hatching. They penetrate the superficial plant tissue of pods, leaves and shoots with their buccal stylets to imbibe the sap and also, nectar. After 2 to 3 weeks, the nymphs reach the 2nd instar. Fully developed, they will hibernate in the ground at a depth of 20 to 35 cm.
- "Pupa": "pupation" occurs the following spring without further feeding. The adult emerges during mid-May at the earliest.
- One generation per annum.
- The 2nd instar nymphs hibernate in the ground. The adults appear from mid-May and mainly in June. They oviposite in June and July. The eggs hatch 5 to 10 days later.
- By gradually emptying the cells, the nymphs weaken shoots; the flowers shrivel or remain sterile. During late attacks on pods, traces of feeding punctures are visible, which are typically shiny. The pods remain small, sterile and may dry up and drop off. Attacked tissue, devoid of cell sap, develops into corky spots. Late sowings and late varieties of peas are particularly vulnerable.
- The presence of 250 eggs per 10 flowers reduces the harvest by up to 60%.
- Swarming is promoted by hot dry weather at the beginning of Summer, in particular, on light soils. Heavy rainfall significantly reduces the thrips population.
- For peas (*) , thrips is more harmful to garden crops than field crops.
- Early cropping and the selection of early varieties is of great importance. Since the thrips overwinters in the ground, a sensible rotation is advisable. The tolerable levels for peas are 20 nymphs or eggs per 10 flowers, for the field bean, 2 individuals per flower.
- Throughout Europe, from the British Isles to the Urals, wherever peas are grown; in Germany mainly in the North. In Austria, field beans suffer heavy harvest losses when the thrips population is high at the start of the flowering period.
DE: Erbsenblasenfuß ES: Trips del guisante FR: Thrips du pois IT: Tripide delle leguminose PT: Tripes da ervilha GB: Pea thrips
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