Figwort weevils

Figwort weevil adults and larvae feed on the shoot tips and flowers of figworts, buddleia, Phygelius and Verbascum.

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

Quick facts

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

What are figwort weevils?

Weevils are a group of several families of beetles in the superfamily Curculionoidea, there are more than 500 species in the UK. All feed on plant material, mostly live plants but a few feed on dry seeds (grain weevils) or rotting wood. Most do not cause noticeable damage to garden plants and several species are uncommon. 

Figwort weevils are several closely related Cionus and Cleopus species of beetles. Both the adult weevils and the larval stage eat the foliage and flowers of Figworts, buddleias, Cape fuchsia and Verbascum 

Symptoms

Plants most commonly fed upon by figwort weevils include Phygelius, Buddleja globosa, Scrophularia and Verbascum

  • Several species of weevil (Cionus and Cleopus species) partly eat leaves which can lead to foliage drying up, particularly at the shoot tips. Flower buds can also be affected
  • 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 yellowish-brown grubs with black heads
  • The larvae feed on leaves by grazing the surface of the leaf. The remaining tissues can dry up and become brown or white
  • Fully grown larvae spin spherical brownish cocoons on the plant stems in which they pupate, these can appear seed like

Control

Check susceptible plants frequently from spring onwards so action can be taken before a damaging population has developed. When choosing control options you can minimise harm to non-target animals by starting with the methods in the non-pesticide control section. If this is not sufficient to reduce the damage to acceptable levels then you may choose to use pesticides. Within this group the shorter persistence pesticides (that are usually certified for organic growing) are likely to be less damaging to non-target wildlife than those with longer persistence and/or systemic action.


Non-pesticide control

  • Where possible accept these weevils as part of the biodiversity a healthy garden can support or tolerate their presence. Damage to plants is often minor and they rarely cause long term damage to the host plants
  • Where feasible the weevils and larvae can be removed by hand picking
  • Encourage wildlife in the garden, such as birds, frogs and predatory ground beetles who will eat the larvae and sometimes the adult beetles

Pesticide control

The RHS believes that avoiding pests, diseases and weeds by good practice in cultivation methods, cultivar selection, garden hygiene and encouraging or introducing natural enemies, should be the first line of control. If chemical controls are used, they should be used only in a minimal and highly targeted manner.
 
  • Organic contact insecticides containing natural pyrethrins (e.g. Bug Clear Gun for Fruit & Veg, Neudorff Bug Free Bug and Larvae Killer). These pesticides although broad spectrum have a very short persistence and so may require reapplication to keep beetle numbers in check.
  • More persistent contact-action insecticides include the synthetic pyrethroids lambda-cyhalothrin (e.g. Westland Resolva Bug Killer), deltamethrin (e.g. Provanto Ultimate Fruit & Vegetable Bug Killer, Provanto Sprayday Greenfly Killer) and cypermethrin (e.g. Py Bug Killer)
  • A broad spectrum systemic insecticide containing the active ingredient Flupyradifurone (Provanto Smart Bug Killer) is available for use on ornamentals and selected edibles
  • The systemic neonicotinoid insecticide acetamiprid (e.g. Bug Clear Ultra) is also available
Follow label instructions when using pesticides.
Plants in flower should not be sprayed due to the danger to bees and other pollinating insects.
Inclusion of a pesticide product does not indicate a recommendation or endorsement by RHS Gardening Advice. 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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