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Frankliniella occidentalis (Pergande)
Insecta, Thysanoptera, Thripidae .

Western flower thrips

Description, Biology, Life Cycle, Damage, Common Names, Images

- Adult: male 0.9 to 1.1 mm long, female 1.3 to 1.4 mm. Antennae: 8 segments. Colour varies, from reddish-yellow to mid-dark brown. Winter populations are darker in colour (*) .
- Egg: 0.2 mm long, pearly-white in colour, more or less kidney-shaped, depending on degree of development (*) .
- Nymph: yellowish body, reddish eyes, at all instars (*) .

- Apolyphagous species.
Attacks fruit trees (peach, plum, apple, vines, etc.) and vegetable plants (bean, aubergine, capsicum, strawberry, tomato, etc.).
It also feeds on cultivated flowers, including: Chrysanthemum, Cyclamen, pinks(Dianthus), Saintpaulia.
This thrips lives for preference in flowers, but also on shoots, buds (between the scales) and fruits, both in glasshouses and in the open. It settles on both surfaces of foliage, but more frequently on the underside.
- Adults: reproduction is parthenogenetic; males are usually rare.
During its life, the female produces up to 40 eggs which she lays in the plant, inserting them one by one; they remain slightly protruding.
Longevity of the adult varies with the climate: in Italy, it may reach 15 days, compared with 40 days in California.
- Nymphs: during the first two instars they feed off the plant, moving to the soil at the end of N2. There follow two instars where the nymph, although active, does not feed: the pre"pupa" (stage lasting 2 days) and the "pupa".

[R]Life Cycle
- In Italy, 5 to 7 generations usually occur each year.
- The full developmental cycle takes 15 days at 25_C and up to 40 days at 15°C.

The most severe damage (*) is caused by the laying of eggs.
Their feeding causes damage not so much by direct piercing but because the injected saliva causes reactions in the plant.
Tissue on which the thrips has fed becomes speckled and peppered with small holes; it is also severely discoloured, particularly in the case of petals. Infestation may also cause major deformity of host plants. A small number of individuals suffices to cause major damage.
This thrips transmits TSWV to various plants (in particular to Chrysanthemum and Gloxinia), which causes major damage.

[R]Common Names
DE: Blütenthrips ES: Trips californiano FR: Thrips IT: Nuovo fitomizo delle serre PT: Frankliniela GB: Western flower thrips, Alfalfa thrips

[R] Images

  1. Frankliniella occidentalis (Pergande) (Coutin R. / OPIE)
    Adult on flower petal
  2. Frankliniella occidentalis (Pergande) (Coutin R. / OPIE)
    Eggs deposited on a flower petal
  3. Frankliniella occidentalis (Pergande) (Rasplus J.-Y. / INRA Versailles)
  4. Frankliniella occidentalis (Pergande) (BASF)
    Damage on lettuce
  5. Frankliniella occidentalis (Pergande) (BASF)
    Detailed picture of damage on lettuce
  6. Frankliniella occidentalis (Pergande) Adult (Pinot Y. / INRA Montpellier)

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