The iris sawfly (Rhadinoceraea micans) is a species of sawfly in the family Tenthredinidae. [2] Native to Europe, the larvae—more often noticed than the adults—can occur in large numbers causing damage to garden plants such as the yellow iris or flag, Iris pseudacorus. [3]

Iris sawfly. The greyish-brown caterpillar-like larval stage of iris sawfly can defoliate flag iris and other waterside irises in summer.

Large populations of species such as the pine sawfly can cause substantial damage to economic forestry, while others such as the iris sawfly are major pests in horticulture. Outbreaks of sawfly larvae can defoliate trees and may cause dieback, stunting or death.

Sawfly caterpillars on Iris The Yellow Iris that’s often planted in damp areas around garden ponds is commonly fed upon by the Iris sawfly, Rhadinoceraea nicans. The caterpillars are frequently found feeding gregariously on waterside irises and may cause severe defoliation.

Rhadinoceraea micans - Iris Sawfly. Benson (1952) considered this a rather local species north to Cheshire. It is now known to occur widely throughout England and Wales north to Durham, and can be fairly easy to detect (including as a larva), hence something of a range expansion seems to have occurred (Musgrove, 2023).

The Iris Sawfly, Rhadinoceraea micans, is a species of sawfly in the family Tenthredinidae. Native to Europe, the larvae — more often noticed than the adults — can occur in large numbers causing damage to garden plants such as the Yellow Iris or Flag, Iris pseudacorus.

There is only one sawfly species that feeds on yellow flag iris and other water-side garden irises: the Yellow Flag Sawfly (Rhadinoceraea micans).

The adult sawfly has a black body with two pairs of dark grey wings, the female of which lays its eggs on iris leaves in late April-May. The caterpillar like larvae emerge in June-July and grow to approximately 25mm (1”) long, when fully fed they burrow into the soil to …

The adult sawfly is all black and most commonly encountered flying around its host plant, Flag Iris. The larvae feed on this plant but have also been found on other irises.

Iris Sawfly Rhadinoceraea micans (7-8mm) is totally black and usually seen flying around Yellow Iris which is the larval foodplant. Phymatocera aterrima has a similar appearance, but has longer antennae and feeds on Solomon's seal.