Eggs may be dislodged and small caterpillars may become stuck or drown. Predators and parasites also impact on population numbers. When fully mature, the caterpillars crawl to the ground, burrow into the soil and pupate. The length of the pupal stage depends on several environmental factors and varies from two weeks to several months. Results from native budworm traps together with other pest and disease alerts are published weekly throughout the growing season in PestFax.
Crops vary in their attractiveness to the moths as sites for laying their eggs.
Feeding behaviour of caterpillars also differs with crop. Field pea, chickpea, lentil and faba bean crops are very susceptible to all sizes of caterpillars during the formation and development of pods. Tiny caterpillars can enter emerging pods and damage developing seed or devour the entire contents of the pod. A field pea pod with the entire contents eaten. Fungal infections may be introduced via caterpillar feeding, especially in faba bean and albus lupin pods.