The eastern tent caterpillar is a pest native to the United States whose presence was first recorded in the mid-1600s. Found in the eastern and central United States, it has been seen as far west as the Rocky Mountains. It appears in large numbers, generally every ten or so years.
When populations are large, elm leaf beetle larvae and adults can completely defoliate elms. Adults chew small, circular holes. Infested trees appear drought-stricken and brown or scorched. After the beetles feed, only the lacy vein structure of the leaf remains. Leaves quickly turn brown, curl and detach.
Eriophyid mites are the smallest arthropod pests on plants. Two common eriophyid mites are ash flower gall mite (Eriophyes fraxiniflora) and pine bud mite/needle sheath mite (Trisetacus pini). Because the mites have relatively short mouthparts, they feed on cells just under the plant surface and may cause galls, witches broom and browning or yellowing of leaves or needles.