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Description, Biology, Life Cycle, Damage, Common Names, Images
[R]Biology
- host plant: apple.
- Mean fecundity: 25 eggs in 4 to 5 weeks.
- Egg: time until hatching, 4 to 12 days.
- Larva: developmental duration, 3 weeks.
- Pupa: developmental duration, 10 days.
[R]Life Cycle
- 1 generation per year.
- The adult emerges from the pupa between mid-May and mid-June. For about a fortnight, it feeds by taking small bites from the leaves of trees. It then conceals itself beneath the bark of apple or forest trees, or beneath stones, dead leaves, etc., and remains in diapause until the following spring (aestivo-hibernation). It leaves its hiding-place between mid-February and the beginning of April when the mean daily temperature has been at least 9°C for a number of days. The time of emergence can thus vary from one orchard to the next, according to differences in microclimate. The diurnal beetle feeds by piercing stage-D buds (*) . 10 to 15 days after emergence, it has reached sexual maturity and mates. 3 days later, the female deposits eggs singly, each inside a flower bud intermediate between stages B2 and C2 (*) .
- The larva feeds on the reproductive parts (ovaries and stamens) and inner surface of the petals.
[R]Damage
Since the larva feeds on the plant's reproductive parts, does not open and takes on a "clove-like" appearance (*) (capped blossom). If bud-bursting is slow (cold spring), the apple weevil can lay all its eggs in buds at the prefered stage. In this case, the damage is much more serious. In years when apple bossom is abundantputs out abundant flowers, the damage done is limited and the weevil even acts as natural, and beneficial, "thinner" (apple blossom is abundant once every two years). A close watch should be kept on apple trees close to woods or abandoned orchards.
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