Fall Webworm Alert: What You Need to Know

Host Trees
Fall Webworms have a wide range of host plants, with favorites including:

• Walnut
• Cherry
• Hickory
• Crabapple
• Birch
  
  

These pests have been documented feeding on over 88 different plant species.

Identification and Life Cycle

• Tents and Timing:
  Unsightly silken tents are starting to appear on tree branches. This is the work of the Fall Webworm, another insect affecting our trees this season.

• Lifecycle Overview:

  • Hatching: As goldenrod begins to bloom, Fall Webworm larvae hatch.
  • Development: The caterpillars can go through as many as 11 instar stages before maturing into adults.
  • Webs: These caterpillars create their characteristic tents at the ends of branches.
    
    

• Do You Need to Act?
  
  Since Fall Webworms appear late in the growing season, they typically don’t require control measures as they do not significantly harm the tree.

Management Options

1. Physical Removal:

   • If you find the nests particularly unsightly, they can be dislodged with a strong stream of water.
   • Pruning can remove the nests, but be cautious, as this may also remove healthy branches with buds for the next growing season. Pruning can be done at any time since these caterpillars remain within their webs while feeding.
     
     

2. Pesticide Treatment:

   • Consider using Bt (Bacillus thuringiensis) if pesticide treatment is necessary.
     
     

3. Natural Control:

   • Fall Webworms have several natural predators, including birds, predaceous bugs, and parasitic wasps. Allowing the webs to remain intact can support the development of these natural enemies.