Magnolia scale insects have an interesting life cycle. Female scales lay their eggs from mid-summer to fall, and new scale insects hatch between August and October. These babies (called crawlers) spend the winter tucked away on branches, then start feeding and growing again in the spring. As they get older, they produce increasing amounts of honeydew. By the time fall rolls around, the adult females die, leaving behind a hollow brown shell.

The crawler stage, which happens in late summer and early fall (typically August to October), is when treatments are most effective. Targeting the crawlers during this window helps stop the next generation before they settle and grow their protective coatings. Planning your treatment for this time of year gives you the best chance of keeping your magnolia scale problem under control.