Predicting Etiella moth activity in 2025

Key takeaway: Adult Etiella moths must be controlled before they lay eggs because larvae burrow into pods and are protected from sprays. This year, moth flights may start later than in 2024. Use the SARDI degree-day model to predict peak moth activity. While crops are green, sweep weekly after 300 degree days. One to two moths per 20 sweeps indicates action is needed.

Effective protection against Etiella behrii, or the lucerne seed web moth, requires a unique strategy compared to most moth pests in grain crops. Success depends on timely action against the adult stage, and not the immature, larval stage.

Why timing matters

As the weather warms up in September and October, adult Etiella moth, start emerging from their pupal stage after overwintering. Female moths will then lay their eggs in susceptible legume crops, including lentils, field pea, lupins and lucerne seed crops.

Within 24 hours of hatching, the larvae will burrow into plant pods, where they will feast and fatten themselves up on the developing grain. This can quickly reduce both yield and seed quality.

Sheltered inside the pod, the larvae are also protected from insecticides. The larvae won’t emerge from the pods until they are ready to pupate in the soil. By then, the damage to the developing grain has already been done.

The key to protecting your crops is to target the adult moths before they lay eggs, preventing the first spring generation of larvae from damaging grain.

Forecasting Etiella activity

To stay one step ahead of Etiella moths, use the SARDI Etiella degree-day model.

By tracking local temperatures from 21 June onward, this tool predicts when adult moths will take flight, helping you plan monitoring and sprays if needed, at exactly the right time.

It is recommended that monitoring begins at 300 degree-day accumulations.

Once the degree-day accumulations hit 351, we can expect about 10% of their flight activity to have begun.

What to expect in 2025

This winter, many pulse-growing regions in southeastern Australia fell within the average temperature range. Overall, we expect peak Etiella moth activity to occur later than in 2024, when a very mild winter brought on early spring flights.

Using the SARDI degree-day model, we’ve compared degree-day accumulations in four major pulse-growing regions between 16 September 2024 and 16 September 2025. The results show degree-days are not accumulating as rapidly this year, which delays the peak of adult moth flights (Table 1).

To keep track of degree-day accumulations and recommended monitoring dates, run the model for your region:

How to monitor for Etiella

Use a sweep net to monitor for Etiella moths at least once a week while crops are green (dry crops aren’t at risk). A minimum of 3 sets of 20 sweeps should be randomly undertaken within each crop.

The recommended threshold is 1-2 Etiella moths in 20 sweeps.

Learn more

Lucerne seed web moth Pestnote, Cesar Australia and SARDI

Cover image: Photo by SARDI