Aquilegia sawfly

The larval stage of aquilegia sawfly feeds on the foliage of Aquilegia in early summer.

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Aquilegia sawfly damage

Quick facts

Common name: Aquilegia sawfly
Latin name: Pristiphora rufipes
Plants affected: Aquilegia
Main symptoms: Foliage is eaten by pale green caterpillar-like larvae
Caused by: Larvae of a sawfly
Timing: May-September

What is aquilegia sawfly?

Sawflies are a group of insects suborder (Symphyta) of the Hymenoptera (bees, ants and wasps). There are about 500 species of sawfly in Britain. They have caterpillar like larvae that feed on plant material and are named after the saw like egg laying organ used by females to lay eggs in plant material. Adults can come in a range of colours many are black, green orange or striped yellow and black. Most are small (< 1cm) but some species such as the Birch sawfly (Cimbex femoratus) can be over 2 cm long. Several species can be found in gardens and are part of the biodiversity a healthy garden will support. More information can be found at The Sawflies of Britain and Ireland webpages

Aquilegia sawfly larva eats the leaves of aquilegia.

Symptoms

Aquilegia sawfly larvae feed in large groups and can defoliate aquilegia plants quickly. Be alert for early signs from early May.

  • Pale green caterpillar-like larvae with yellowish brown heads and up to 1cm long. They feed on the edge of leaves whilst lying with most of the body beneath the leaf blade
  • Complete defoliation can sometimes occur, although plants often recover
  • The adult insect is a black, grey winged insect about 5mm in length

Control

Check aquilegia 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 tolerate populations of aquilegia sawfly, plants often recover from defoliation and may not be affected every year
  • Encourage predators and other natural enemies of sawfly in the garden, such as birds and ground beetles.
  • Check plants regularly from may for the presence of larvae and remove by hand where practical
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.

  • If numbers of larvae are too high for hand picking, control may be achieved by spraying with pesticides. Spraying at dusk is likely to give the best results
  • Organic contact insecticides containing natural pyrethrinrum (e.g. Bug Clear Gun for Fruit & Veg, Neudorff Bug Free Bug and Larvae Killer). Several applications of this short persistence products may be necessary to give good control
  • 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 systemic 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

Pesticides for gardeners (downloads pdf document outlining pesticides available to home gardeners)
 

Biology

Adult aquilegia sawfly are black-bodied insects, up to 5.5mm long, with two pairs of blackish grey wings and light brown legs. They appear similar to small flies but are in the same order of insects as bees, ants and wasps, the hymenoptera. They emerge in late spring.

The larvae feed on the underside of the leaves, making large holes from the leaf edge. They take about two weeks to complete development before entering the soil to pupate. Adults emerge from the pupa after a couple of weeks and soon lay eggs. A second generation of larvae can then cause more defoliation. By mid-summer, the stems may have been stripped of foliage. Larvae of the second generation overwinter in pupal cocoons in the soil.

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