Nematodes cannot be totally eliminated from the landscape. The goal is to keep the population low enough to prevent damaging symptoms that weaken the plant. Boxwoods should not be grown in soils heavily infested with nematodes. This is the most serious insect pest that attacks boxwood. When the larvae hatch, they feed inside the leaf, creating a mine.
Adults emerge from the leaves the following spring, just after new growth occurs on boxwoods.
There is one generation per year. Boxwood leafminer attacks result in irregularly shaped swellings on the leaf. There may be a slightly blistered appearance on the leaf s undersurface. Blistering may not be obvious until late summer. Infested leaves typically turn yellow or brown in splotches, are smaller and drop sooner than healthy leaves.