Aquilegia sawfly

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

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Aquilegia sawfly damage
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

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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 larvae eat the leaves of aquilegia.

Symptoms

Aquilegia sawfly larvae feed in large groups and can defoliate aquilegia plants quickly. Watch 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, plants usually recover
  • The adult insect is a black, grey winged insect about 5mm in length

Management

Sawflies can be a part the biodiversity a heathy garden supports. 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 using the methods in the non-pesticide section below. Pesticide treatments are likely to kill natural enemies and are only likely to be successful if the entire plant can be reached.

Non-pesticide 

  • 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 if required and where practical
Pesticides 
The RHS recommends that you don't use pesticides. Most pesticides (including organic types) reduce biodiversity, including natural enemies, impact soil health and have wider adverse environmental effects.
 
Where you cannot tolerate the sawfly, manage them using the information above as your first course of action.
 
Pesticide treatments are likely to kill natural enemies and so reduce the likelihood of natural control and can lead to resurgence of the target animal.
 
The pesticides listed are legally available in the UK. This information is provided to avoid misuse of legal products and the use of unauthorised and untested products, which potentially has more serious consequences for the environment and wildlife than when products are used legally.
 
Always follow the instructions on the products. 
Homemade products are not recommended as they are unregulated and usually untested.
Be aware that products such as Neem are not registered for use in the UK and we cannot advise they are used.
 
  • If numbers of larvae are too high for hand picking, control may be achieved by spraying with pesticides. Spraying at dusk is likely to be more effective
  • Organic contact insecticides containing natural pyrethrum (e.g. Bug Ultra 2, Neudorff Bug Free Bug and Larvae Killer). Several applications of this short persistence products may be necessary to give good control
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, plants will usually recover. Larvae of the second generation overwinter in pupal cocoons in the soil.

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