Hello Carrie,

You didn’t make the situation worse — and you don’t need to tape over the tree. The best approach in Michigan is to remove egg masses, protect the bark, and use proven Integrated Pest Management (IPM) methods rather than sealing the crook. More information at this link:

Dealing with Spongy Moth Around Your Home or Property - Integrated Pest Management

Below is a clear, Michigan‑specific plan based on university extension guidance.

What to Do Now (Michigan Extension–Based Guidance)

1. Do NOT wrap or tape over the tree crook

Arbor tape, duct tape, or plastic wrap will not stop emerging caterpillars and can trap moisture, causing bark rot or fungal problems.

Michigan State University Extension recommends physical removal rather than sealing tree wounds or cavities. More information at this link:

Dealing with Spongy Moth Around Your Home or Property - Integrated Pest Management

2. Remove Remaining Egg Masses Properly

Even if the nests broke apart, you can still reduce the population.

How to remove egg masses (MSU Extension method)

Scrape egg masses into a container of soapy water (not just water) and leave them submerged for 48 hours.

Do not crush them on the tree — this can leave viable eggs behind.

Use a putty knife or stiff brush to reach into the crook.

If you already removed most of the material, you’ve done the right thing.

3. Protect the Tree This Spring

Spongy moth caterpillars hatch in late April–May in Michigan. Early intervention is most effective.

A. Burlap banding (recommended)

Instead of sealing the crook, use burlap bands around the trunk in late May–June:

Wrap a strip of burlap around the trunk at chest height.

Tie a string around the middle, so the top half hangs like a flap.

Caterpillars hide under the flap during the day — you can remove and destroy them daily.

This is a standard IPM method used by MSU and other universities. More information at this link:

Dealing with Spongy Moth Around Your Home or Property - Integrated Pest Management

B. Bacillus thuringiensis kurstaki (Btk)

A biological insecticide effective on young caterpillars (under ¾ inch).

Safe for fruit trees when used according to label directions.

Apply in early May when hatch begins.

C. Tree health support

Purdue Extension notes that healthy deciduous trees usually recover even after heavy defoliation, as long as they aren’t stressed by drought. More information at this link:

Management

Water deeply during dry spells.

Mulch (but keep away from the trunk).

Avoid pruning during infestation unless necessary.

4. What Happens if Some Cocoons Remain?

Pupae that fell deeper into the crook will emerge as moths only once and then die.

The real damage comes from next year’s caterpillars, not the adults.

Removing egg masses now is the most important step.

5. When to Call a Professional

If you see:

Multiple egg masses (more than 10–15 on the tree)

Repeated defoliation year after year

Large trees you cannot safely treat

An arborist can apply Btk or other targeted treatments at canopy height.

Summary: What You Should Do Next

Do not tape or seal the crook — it harms the tree and doesn’t stop caterpillars.

Scrape any remaining egg masses into soapy water for 48 hours.

Plan for spring control: Btk spray early, burlap bands later.

Keep the apple tree healthy to help it withstand any feeding.

I hope this helps!