Spongy Moth (Lymantria dispar)
GDD Window (base 50): 90-448
Overview:
- Overwinter as egg masses covered in yellowish fur, 1.5 inches long and ¾ inches wide on trees, stones, walls, furniture, etc.
- Young caterpillars are black and hairy
- Older caterpillars are 2 inches long with 5 pairs of blue dots and6 pairs of red dots along their backs
- Male moths are brown with a darker brown pattern on their wings
- Females are white, slightly larger than the males, and have wings but do not fly -Adults appear two weeks after pupae
- Trees may be completely bare of leaves (3 consecutive yrs of 75% defoliation will set trees up to be killed)
- Heavy infestations will look barren and wintery in the summer
- Host plants: over 300 species of trees and shrubs
Management:
Cultural Practices:
- Natural Predators: Entomophaga maimaiga fungus, Nuclear polyhedrosis virus (NPV), Clostridium bacteria
- Report sightings to agriculture officials
- Follow quarantine regulations
- Crush pupae or brush it into a container or soapy water using a disposable object
- Apply a trap/burlap banding or sticky banding to capture caterpillars
- Soak egg masses in soapy water for a few days before disposing
- Crushing eggs will not work
- Reduce tree stress
Materials:
- Contact insecticides:
- Pyrethroids [3]: –thrins
- Permethrin, bifenthrin
- Carbamates [1A]: carbaryl
- Pyrethroids [3]: –thrins
- Systemic insecticides: (larvae only, ~June application):
- Neonicotinoids[4A]: acetamiprid (reduced risk)(translaminar)
- Organophosphates [1B]: acephate (translaminar)
- Diacylhydrazines [1B]: Diflubenzuron (IGR)
- Considerations:
- Will harm non-target species
Biorationals:
- Bacillus thuringiensis (Btk)
- Microbial disruptors of insect midgut
- Only for populations less dense than1000 eggs per acre
- Most effective when applied in the spring (1st & 2nd instars)
- Insecticidal soap (young instars)
- Spinosyns [5]: spinosad (translaminar)
- Diamides [28]: Chlorantraniliprole
Disclaimer – Materials do not cover all possible control scenarios and are intended for licensed professionals. Tradenames do not imply endorsement and are used as examples. You must strictly follow the label for each compound prior to use. Rutgers is not responsible form is used materials or damages thereof. The label is the law. Labels will provide detailed information on use and restrictions. Additionally, application intervals, compatibility, surfactant use, PHI, PPE, important and other key information is described in detail. Always discuss treatments with your local agents. Note: Neonicotinoids can only be legally applied in commercial agriculture settings by licensed applicators. Guidelines and recommendations made in this presentation are specific to the state of New Jersey.