Willow Leaf-Rolling Caterpillars: Cocoons in Leaves, Low Impact

Case

Willow: cocoons wrapped in leaves, other leaves nibbled. Japanese beetle battle distracted owner. Tree size unknown.

Expert Assessment

• Likely caterpillars (leaf-rollers/tier-makers) pupating in leaf rolls.
• Large tree = minimal health impact.
• Cocoons protect pupae → sprays ineffective.

Action

1. Collect affected leaves → County Extension or nursery for ID.
2. If caterpillars: Bt (Bacillus thuringiensis) or Thuricide on foliage (coverage challenge on large tree).
3. Rake/destroy fallen leaves (sanitation).

Reality Check

Mature willows tolerate heavy defoliation. Focus on tree vigor (water, mulch). Don't panic over leaf-rollers.