Optimal Conditions
The warm and relatively dry conditions of mid-autumn (and mid-spring) are their time to party.
Signature
Quickly decimated brassica plants, with tiny black droppings in the base of the stems.
Prevention
The moths are territorial, so dummy butterflies should deter them from laying their larvae. But if you’re serious about preventing them, it’s worth putting fine netting over the patch that will restrict landing space for the moths to lay their larvae. Make sure the netting is fine enough to prohibit them from entering the veggie patch and is not draped over the plants themselves, as this will render the netting useless.
Coping
A search and destroy mission is useful. We like to reward our kids for caterpillar kills
Eradicating
If you turn your back and things have gotten out of hand, dipel bacillus thuringiensis– a bio-insecticide spray – will drastically reduce their numbers. A couple of sprays, a few days apart when it is not raining, will kill all living caterpillars. But to ensure they don’t come back, netting needs to be constructed.
