Because rosette buds are larger, hollow, and more rounded than normal buds, they are easily filled with hundreds of microscopic, eriophyid mites. As a result, rosette buds either do not break in the spring or break to form multiple, weakened shoots. Although root aphids feed on large roots, their feeding causes no damage. They are often associated with ants, which feed on the honeydew of the aphids. The ants create tunnels and galleries to reach the aphids, thus loosening the soil and sometimes damaging the trees.
White grubs are the larva of scarab beetles.
The grubs live in the soil and eat roots for two to three years before emerging as adult beetles. Adults lay eggs in short grass in May and June. White grubs are associated with pastures and will damage the roots of trees planted on these sites. Look for grubs in summer and fall by digging and sifting the soil.