Figwort weevils

Figwort weevils are easily overlooked until the damage caused by the beetles and their larvae to the shoot tips and flowers of figworts, buddleia, Phygelius and Verbascum becomes obvious.

Figwort weevil (Cionus sp.) on Figwort (Scrophularia sp.). Credit: RHS/Entomology.

Quick facts

Common name Figwort weevils
Scientific name Cionus and Cleopus species
Plants affected Figworts (Scrophularia species), buddleias - particularly Buddleja globosa, Phygelius species and Verbascum species
Main symptoms Small greyish-white beetles with black circular marks on the wing cases or slug-like beetle larvae  present on the plants. Leaves at the shoot tips and flowers are eaten
Most active May-August

What are figwort weevils?

Figwort weevils are several closely related Cionus and Cleopus species of beetles. Both the adult weevils and the grub stage spoil the appearance of host plants by eating the foliage and flowers.

Symptoms

Plants most commonly attacked by figwort weevil include Phygelius, Buddleja globosa, Scrophularia and Verbascum

  • Several species of weevil (Cionus and Cleopus species) partly eat leaves which lead to foliage drying up, particularly at the shoot tips. There is also likely to be damage to flower buds
  • The adult beetles are black and greyish white and are up to 4-5mm (about 1/8in) long, with one or two black circular marks where the wing cases meet
  • The larvae are up to 6mm (about ¼in) long and are slimy, yellowish-brown grubs with black heads
  • The larvae feed on leaves by grazing the surface of the leaf. The remaining damaged tissues dry up and become brown or white

Control

Non chemical control

  • The weevils and larvae can be controlled by hand picking

Chemical control

  • Pesticides are likely to be more effective on larvae than adults
  • Heavy infestations which are impractical to remove by hand can be treated with pesticides
  • Organic insecticides containing natural pyrethrins (e.g. Bug Clear Gun for Fruit or Defenders Bug Killer, ecofective Bug Killer (also contains fatty acids)). Several application of these short persistence products may be necessary to give good control
  • Synthetic pyrethroid pesticides such as lambda-cyhalothrin (e.g. Westland Resolva Bug Killer), or deltamethrin (e.g. Bayer Sprayday Greenfly Killer) can be used
  • The systemic neonicotinoid insecticide acetamiprid (e.g. Bug Clear Ultra) can also be used
  • Plants in flower should not be sprayed due to the danger to pollinating insects
  • Inclusion of a pesticide product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener

Download

Pesticide for amateurs (Adobe Acrobat pdf document outlining pesticides available to gardeners)

Biology

  • Adult weevils overwinter in soil, leaf litter and other sheltered places
  • They emerge in May and June when they seek out host plants on which they lay eggs
  • There are two generations during summer between May and late August
  • When fully grown, the larvae spin spherical brownish cocoons on the plant stems in which they pupate
  • These cocoons closely resemble the seed pods of figwort

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