Look out for Etiella

There have been unconfirmed reports of Etiella (Etiella behrii) in Horsham and near Ballarat, in the Wimmera and Western districts of Victoria, respectively. Etiella is a sporadic pest of lentils in southern Australia. They also attack lucerne, field peas and pasture legume crops. Successful control relies on thorough crop monitoring, with management mostly based on timing insecticide sprays to target adult moths within the crop before egg lay commences.

Etiella moths (also known as the ‘lucerne seed web moth’) are slender, 10-15 mm long, grey-brown in colour and have a prominent beak. At rest, their wings are held over the body and the forewings have a distinct white strip running the full length along the front edge. Larvae grow up to 15 mm long, are cream-pale green in colour with several pink-red stripes running along the back and have a red-brown coloured head.

Female moths lay their eggs under the calyx or on the pod surface, and these hatch in 4-7 days depending on temperature. Newly hatched larvae bore into immature pods within 24 hours to begin feeding on developing grain. This results in inferior quality lentils and yield losses due to a reduction in grain weight and grain breakage. Once inside the pods, larvae are protected from insecticide sprays and damage is usually only identified at harvest.

A degree-day model can be used to identify the onset of major flight activity of Etiella moths. The date when the cumulative total of degree-days first reaches 351 is the date to commence in-crop monitoring. No further temperatures need to be recorded after a value of 351 has been reached. According to the model, crops in most districts should now be monitored. For information about the Etiella degree-day model, click here.

Sweep netting is a common method used for estimating Etiella moth numbers in crops. Lentil crops should be sampled at least once a week during podding for evidence of Etiella activity. A minimum of 3 groups of 20 sweeps should be randomly undertaken within each lentil field. Recommended action thresholds are 1-2 Etiella moths in 20 sweeps.

For more information on Etiella and for images, click here.