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

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

• 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

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

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.