Diagnosing lucerne seed web moth in lupins and peas
The larvae of the lucerne seed web moth (Etiella behrii - also called Etiella web moth) is an infrequent pest of peas and lupins. Late sown crops and crops near lucerne are at most risk.
What to look for
- Pods contain chewed developing seed with jagged edges, silken webbing, droppings, and often a small cream to green caterpillar. During the early stages of an attack, there are few signs of damage. Often the pods must be pulled apart before damage can be seen.
Larger caterpillars mesh pods together with webbing and chew them.
Plant
- Cream to green caterpillars up to 20mm long with a reddish-brown head and light red stripes running along the back. These stripes are more pronounced in young larvae.
Insect Larvae
- Grey-brown slender moth up to 12mm long with a protruding 'beak'.
Insect Adult
What else could it be
| Condition | Similarities | Differences |
|---|---|---|
| Diagnosing native budworm in narrow-leafed lupins | Chewed seed in green pods | The pod has a clear hole with only chewed seed inside, and the caterpillar remains outside. |
Where did it come from?
- Lucerne seed web moth is a native insect that occurs on a wide range of native and introduced legume plants. Cultivated hosts include medics, clovers, lucerne, field peas, lupins, vetch, lentils and soybeans.
- Lucerne seed web moths have three to four generations each year in spring, summer and autumn.
- Adults are first seen late in the season. Adult females lay about 200 eggs which may hatch within 24 hours in warm weather, but may take up to two weeks to hatch in cool weather. Four to seven days is common. Each egg hatches into a small larva which constructs a tunnel-like silk tube, around itself, with one end attached to the surface of the pod.
- In autumn, mature larvae drop to the ground and spin cocoons in the soil and do not develop into pupae until spring.
Management strategies
Grass pasture control
- Etiella does not usually cause economic damage in lupin unless there are plant hosts such as lucerne growing nearby over summer.
- Removing early season volunteer legume plants near lupin crops will help control Etiella.
- Monitor early, as insecticides will only control larvae present on the outside of pods. Check for webbing in flowers and growing point of the plant.
Where to go for expert help
Page last updated: Monday, 1 May 2017 - 11:47am