What's eating my burr oak?

Burr Oak is attacked by gypsy moth and oak leafroller caterpillars, two-lined chestnut borer, and various oak gall wasps. Deer browse seedlings and young saplings heavily. Squirrels are the primary acorn predators. Burr oak is more borer-resistant than many oaks but drought stress opens the door to secondary pests.

Mass defoliation in late spring; repeated years of defoliation weaken and eventually kill trees; egg masses on bark in winter Scrape and destroy egg masses; apply Bt spray to young caterpillars in May; use sticky tree bands; for outbreak areas, aerial Bt application by authorities

Serpentine galleries under bark of stressed branches; branch dieback starting at crown; D-shaped exit holes in bark Keep trees well-watered during drought; prune and destroy infested limbs before adults emerge in spring; no effective curative chemical

Round, bullet, or woolly galls on leaves, stems, or acorns depending on species; rarely fatal but disfiguring; galls on acorns reduce crop Prune gall-bearing twigs in winter; no chemical control is practical or necessary on established trees; tolerate cosmetic damage

Bark rubbed by antlers (rutting damage); seedlings and saplings browsed to stubs; repeated browsing prevents establishment Install wire-mesh tree shelters or hardware cloth around trunks; use repellent sprays on young trees; deer fencing for nursery blocks