Stone fruit bud weevil

Anthonomus bituberculatus

Profile

The stone fruit bud borer is a weevil which can cause damage to apricot, plum and damson. The feeding activity of the beetles destroys the buds of the host plants and leads to sparse, airy shoots in the crowns. Locally, high infestation pressure can develop and ultimately lead to yield losses.

Appearance

The stone fruit bud weevil(Anthonomus bituberculatus) is a 2.7 - 3.3 millimeter long weevil which is mostly brownish red, rarely reddish brown or monochromatic blackish brown in color. Its proboscis is dark, the keel is lined with rows of dots. The neck shield, which has a pale midlongitudinal band, and the elytra base are usually paler reddish than the posterior half of the elytra. The stone fruit budworm is very similar to the pear budworm in appearance and habits.

The larvae are legless and grow up to 6 mm long. They eventually pupate to a yellowish pupa.

Biology

The stone fruit bud borer is a representative of the weevils (Curculionidae). The beetle carries out a ripening feeding in autumn and can destroy the flower and leaf buds of its host plants. After mating, the females lay their eggs on the flower buds and the larvae that hatch from them destroy the buds by feeding inside them. Pupation occurs while still in the bud and the adult beetle hatches from the pupa in the spring. The adult beetle survives in protected places (e.g. bark cracks) to become active again on its host plant in autumn. The stone fruit budworm forms only one generation per year. Nevertheless, a relevant infestation pressure can build up locally in the course of a few seasons.

Damage symptoms

In spring, infested flower buds do not sprout. The inside of the bud is eaten out by the larva and the buds are dead. Beetle larvae or pupae may be found in the damaged buds. Loss of buds may result in sparse, airy shoots in the crowns.

Host plants

The stone fruit bud borer preferentially attacks its main host plant, the weeping cherry(Prunus serotina). However, it can also occur as a pest on important cultivated fruit species such as apricot(P. armeniaca), plum (P.domestica) and its subspecies plum(P. dom estica subsp. domestica). In addition, other wild plants can also be used for development, such as hawthorn(Crataegus sp.).

Distribution

The stone fruit bud borer is widespread from the Near East westwards over almost all of Europe, although there are no records from Spain and Greece. In Central Europe, it can be assumed to occur everywhere.

Economic importance

The loss of buds results in sparse, airy shoots in the crowns and can result in yield losses.

Prevention and control

  • Prevention: Observation of beetle emergence from the beginning of September (tapping the beetles onto a light-coloured surface or into a collecting funnel)
  • If there is a strong local infestation pressure, a targeted autumn treatment is usually sufficient to prevent new infestations in the coming seasons. If plant protection products are currently authorised in Austria against this pest, they can be found in the plant protection product register (see list of plant protection products authorised in Austria)

Last updated: 12.12.2023

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