Etiella moths have been sighted already this year in lentil crops across the southern growing region. Pesticides applied to lentil crops must target adult Etiella moths prior to egg lay because the larval stages of the insect are protected from contact sprays once they have burrowed into the pods. Larvae burrow into pods within 24 hours of hatching.
Etiella moths active in southern lentil crops
by Mary Raynes, Pulse Australia (Industry Development Manager – Southern)
T: 0408 591 193 E: mary@pulseaus.com.au
Etiella moths have been decisively active already in lentil crops across the northern lentil growing regions of southern Australia. Although the peak flight activity for etiella moths is predicted to begin in early to mid-October, moths have already been detected during sweep netting in lentil crops at Kyalite in southern New South Wales, Nyah West and Berriwillock in Victoria’s Mallee region and around the South Australian Roseworthy, Narridy and Sandilands areas.
Since the etiella moth is already definitely active, SARDI entomologists are recommending that growers and advisors check lentil crops now in all regions and consider spraying if moths exceed threshold levels of more than 1–2 moths per 20 sweeps. It is imperative to monitor lentil crops during peak flight for the larvae of etiella as it is the larvae that does the damage to plant. Lentils are susceptible to etiella damage from late flowering onwards, as soon as the first pods appear.
Etiella, or the lucerne seed web moth, with their protruding beak and distinctive white stripe along the edge of the forewing can cause extensive damage to lentil, field pea and lupin grain if left uncontrolled. The grain quality standard allows just 1 per cent of lentil grain to show insect damage, which means that growers will suffer significant losses and additional costs if this pest infests the crop.
The larvae usually only partially eat each seed, often causing characteristic pin-hole damage. Damaged seed is difficult to grade out and the unattractive appearance reduces seed quality. The pods are susceptible to damage while they are green and this pest can have up to three generations per year from spring to autumn. Larvae over-winter in the soil and emerge as adults the following spring.
Pesticides applied to lentil crops must target adult moths prior to egg lay because the larval stages of the insect are protected from sprays once they have burrowed into the pods. Larvae burrow into pods within 24 hours of hatching. As they feed on pods and seeds they leave frass in the pod and may web pods together as they move between pods.
It is important to be ready to control the first generation of this pest as soon as the threshold of 1–2 etiella moths per 20 sweeps occurs (average count from a minimum of three sets of 20 sweeps in a lentil field). Monitor every 4 to 5 days and re-commence monitoring within one week of spraying.
Esfenvalerate and deltamethrin are registered for the control of etiella moths in lentil. Both products provide a high level of control of adult moths and small larvae before they burrow into pods.
Etiella flights commonly occur in mid to late September, frequently coincide with early pod development in pulses. The SARDI degree-day model can be used to predict the peak flight activity each season using daily max/min temperatures from June 21 onwards. The date when the cumulative total of degree-days first reaches 351 is the date to commence in-crop monitoring.
You can download SARDI’s degree day model from the IPM website.
For more information please check the Pulse Australia website and Pestfacts Newsletter.