Lucerne seed web moth (Etiella behrii) in lentils, field peas, lupins, soybeans (WA, SA, VIC, NSW), and peanuts (QLD). Under hot and dry conditions, they may also occur in soybeans in Queensland.
Incidence and abundance varies by season. Severe infestations can result in a loss of yield and quality.
Etiella flights commonly occur in mid to late September and often coincide with early pod development in pulses.
Larvae burrow into pods within 24 hours of hatching. They feed on pods and seeds, remaining in pods until entire content has been eaten.
Frass is left in the pod, and adjacent pods may be webbed together as larvae move between pods.
Frass and larvae in pods, and adjacent pods webbed together as larvae move between pods.
Seeds usually only partially eaten out, often with characteristic pin-hole damage. Damage is difficult to grade out and unattractive appearance reduces seed quality.
Peanuts are at particular risk during end-of-season droughts when the dry soil allows larval access to the pods.
Monitoring
The etiella degree-day model forecasts timing of initial moth flight using daily max/min temperatures from June 21 onwards. Start monitoring for moth flights when the model reaches 351 D-days. For more information and to download the Excel file, visit SARDI.
Early planting of crops should ensure that most pods are set before moth activity occurs in spring
Control weeds (e.g. rattle pods are favourite weed hosts in Queensland)
Thresholds
1-2 etiella moths in 20 sweeps (lentils)
Pesticides
Chemical control of etiella is only effective on adult moths. Once larvae are in pods they cannot be controlled by insecticides.
Successful control relies on thorough crop monitoring in order to time insecticide applications to target adult moths prior to egg lay.
Continue monitoring for 1 week after chemical applications
Multi-pest considerations
Typically only the first generation of etiella are of concern. However, in late finishing seasons, a second generation may also cause significant seed damage.
In some years both helicoverpa and etiella moths can be controlled with one spray.
