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Etiella

Lentil growers should start preparing for potential spring pests, particularly Etiella (Etiella behrii), also known as the lucerne seed web moth. Etiella is a sporadic but serious pest of lentils in southern Australia, and can cause yield losses and damage grain if not controlled. Newly hatched larvae bore into immature pods within 24 hours of hatching to begin feeding on developing grain. Once inside the pods, larvae are protected from insecticide applications so sprays must target adult moths before egg lay commences. Etiella also attack lucerne and occasionally clover, peas and lupins.

The Etiella degree-day model predicts the peak Etiella moth flight period based on local temperatures and this can be used as a guide for when to commence monitoring. Daily minimum and maximum temperatures for a specific location need to be entered from June 21st onwards. The date when the cumulative total of degree-days first reaches 351 is the date to commence crop monitoring. No further temperatures need to be recorded after a value of 351 has been reached. As of 7th August, the cumulative degree-days at some locations were: Horsham (VIC) - 113; Bendigo (VIC) - 93; and Wagga Wagga (NSW) - 115.

Etiella moths are 10-15 mm long, slender, grey-brown in colour and have a prominent beak. The forewings have a distinct white stripe running the full length along the front edge. Larvae are cream-pale green in colour with several pink-red stripes running along the back. They have a red-brown coloured head and grow up to 15 mm long. Female moths lay their eggs under the calyx or on the pod surface, and these hatch in 4-7 days depending on temperature.

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 crop. Recommended action thresholds are 1-2 Etiella moths in 20 sweeps. Pheromone traps and light traps are also useful monitoring techniques. Esfenvalerate, a synthetic pyrethroid, is registered for controlling Etiella in lentil crops in southern Australian states.

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