Insecta, Thysanoptera, Phloeothripidae .
Description, Biology, Life Cycle, Damage, Common Names, Images
- Host plant: olive.
- Adults: winter period is passed in the adult stage with the insects protected in cracks or crevices on olive stems. They resume activity in the following spring when mating and then oviposition occurs, with a total of 250 eggs laid on leaves or in crevices or cracks.
- Eggs: iIncubation period from 9 to 15 days depending on weather conditions.
- Nymphs: the first instar takes about 15 days to reach the "prepupal" stage and after another 3 days reaches the "pupal" stage where it remains for 7 to 8 days before passing to the adult form.
- This pest has 3 generations per year, although in some regions it is possible to have 4, depending on the local climatic conditions.
The lst generation takes about 40 days and the others show no significant differences. The adults from the lst generation copulate 5 to 15 days after emergence and oviposition takes place on new shoots and flower buds. The young nymphs attack shoots, young leaves, flowers and young fruits. Maximum population density is observed in June-July depending on local climatic conditions. During full summer where temperatures are higher (July-August) the adults return to take shelter in cracks or crevices on olive stems until the weather becomes more favourable, usually in September.
The thrips feed by rupturing the epidermal cells and imbibing the sap. The destruction of the attacked cells results in the yellowing and the dessication of damaged areas.
The severity of damage caused by nymphs and adults depends upon the timing of attack. Leaves become deformed by the asymmetric and hardened growth of their tissues. The fruits also become deformed and smaller than normal.
On young trees or during the emergence of new shoots, attacks on new terminal buds may prevent development or cause deformation. On floral buds or young fruits the attack can cause abortion or their destruction with considerable effect on yield (*) , (*) .
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