Diamondback moth biology & life cycle
Adults do not overwinter in Canada but migrate in on southerly winds in May and June. Females lay eggs on the upper surface of leaves. Larvae hatch and "mine" the internal leaf tissue; older larvae feed on the leaf undersurface. The larvae feed for 2 weeks, and then pupate on the plant. Adults emerge 7-10 days later and there are at least three generations per year . All of these can be found on the plant at the same time. Typically, it is the second generation that does the most damage, feeding at the time of flowering and pod development. Yield loss can take place.