Did you know oak is the national tree for more than 10 countries?

Unfortunately, some pests are quite fond of oak trees, too. In spring and summer, hungry caterpillars can’t get enough of oak tree leaves.

The good news is oak trees are notably resilient, but they do need a little help to fight infestations. Read on to identify which type of caterpillar is eating your oak tree and how to control them.

What To Do If Caterpillar Pests Are Eating Oak Tree Leaves

Look at the caterpillars on your oak tree and observe the leaves as well. Then, try to determine which one is eating your tree–and learn how to stop them!

Oakworm Caterpillar

  • How it looks: When young, an oakworm caterpillar is a hairless critter with a big head and a small, yellow-green body. As the pest matures, it turns black.
  • What it does: In spring, oakworms feed on newly sprouted leaves. Groups of these insects devour leaves down to their veins. Sometimes, they completely consume foliage by summertime.
  • When and how to treat: Stop oakworms early on to guarantee a healthy summer canopy. Apply a product that contains Bacillus thuringiensis (Bt), a bio-pesticide, on a sunny spring day when caterpillars are active.

Yellownecked Caterpillar

  • How it looks: True to its name, this caterpillar is yellow with black stripes.
  • What it does: Between late summer and early fall, clusters of yellowneck caterpillars skeletonize leaves. They chomp away one section at a time, so you’ll notice full branches lacking greenery.
  • When and how to treat: You can easily eliminate the pest on small trees by shaking them off. For larger trees, or a more serious infestation, use a product that contains Bt.

Tent Caterpillar

  • How it looks: It’s a hairy pest with a reddish-brown body and small head.
  • What it does: Tent caterpillars start chewing up foliage early in spring. They also weave a silky, spider-like web that makes for an unsightly appearance.
  • When and how to treat: Wait until winter to clip and destroy the silky webs, or stop the caterpillars by adding a tree band in early spring.

Leafrollers

  • How it looks: This is a small caterpillar with a dark head and green or brown body.
  • What it does: Like tent caterpillars, these pests spin silk webs, but they use the webs to tie leaves into a safe feeding area. Over time, leafrollers can defoliate an entire tree.
  • When and how to treat: For small infestations, cut leaves that have leafroller webs. Check back in a week or so to see if new webs have formed, and if so, try treating with Bt.

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