Grey-banded leaf weevil

Consultant, Tim Condon (Delta Agribusiness), reports seeing ‘masses’ of adult grey-banded leaf weevils (Ethemaia sellata) around Harden, in the South West Slopes district of New South Wales. The weevils have been found around house yards and domestic gardens, but have not yet been found affecting any crops. This report follows observations of very high numbers of grey-banded leaf weevil larvae around the district in July this year. The larvae were found closely associated with marshmallow weed, and in some cases had caused complete defoliation to the point of plant death.

Little is known about the feeding ecology of grey-banded leaf weevils. Adults have previously been recorded attacking several winter crops including canola and lupins, and may also be a grain contaminant at harvest. However, it is thought that they may feed preferentially on malvaceous weeds (such as marshmallow weed) and some ornamental plants, and only move into crops when there is a lack of preferred host plants. This species has been recorded as common in gardens, and both adults and larvae are known to attack several ground vegetables.

Adult weevils are approximately 8 mm long, grey in colour with distinctive raised markings (bumps) and a white area on the bottom covering approximately 1/4 of the wing covers (elytra). They are thought to be flightless. Larvae are yellow to green in colour with a light green to brown head capsule, and are often confused with vegetable weevil larvae, which are similar in size and colour. Crops should be monitored closely, particularly near fence-lines, for the presence of weevils moving into crops and causing damage. There are no insecticides currently registered to control grey-banded leaf weevils. However, when synthetic pyrethroids have been used at 400 mL/ha against other pests, they are reported to provide adequate control.

Click here for images of the grey-banded leaf weevil.