Spongy Moth, formerly known as “Gypsy Moth”

Spongy moth is the new common name for Lymantria dispar, formally known as the gypsy moth. ‘Spongy’ refers to the texture of the egg masses, the life stage in which the moth spends most of its life. Read More.

Accidentally introduced to the United States in the 1800’s and originally brought to the U.S. to manufacture silk, it subsequently escaped and has caused extensive foliar damage to a diverse array of deciduous trees. Under wet, rainy conditions, spongy moth populations can be naturally controlled by a fungus (Entomphaga maimaiga), introduced from Japan in 1910. Recently, there has been a resurgence of spongy moth populations in the eastern United States, largely due to prolonged, dry springs, which prevented fungal establishment.

Spongy moth is a forest and urban pest in the eastern United States. Caterpillars feed on a multitude of tree species, and when they reach high population densities, they will feed on almost any tree or shrub. Their preferred species include oak, maple, beech, birch, hawthorn, apple, poplar, and willow.

Download Pest Sheet

• Common Symptoms

  • Dark colored, hairy caterpillars with 5 pairs of blue and 6 pairs of red dots lining their back can be seen in May and June. White female and brown male moths are active throughout July and August. The caterpillars are responsible for tree damage, feeding on foliage and stressing the tree. Trees that are completely defoliated may re-foliate 3-4 weeks after feeding ends; however, this requires the trees to expend an enormous amount of energy. As a result, repeated defoliations may kill the trees or severely weaken them, making them vulnerable to secondary mortality factors.

  Treatments

  • Trunk injection with any of the TREE-äge® family of products and Mn-jet Fe™ will provide both preventative and curative control depending on the time of year treatment is applied. We recommend treatment in late September, which will minimize early pest damage the following spring.

  References And Photo Credits

  • Main photo taken by USDA Forest Service – Region 8 – Southern
    Damage taken by John Ruter, University of Georgia, Bugwood.org
    Egg Masses taken by Cifáre/Slovakia

©2020 Arborjet, Inc. Important: Always read and follow label instructions. Some crop protection products may not be registered for sale or use in all states or counties. Please check with your state or local extension service to ensure registration status. TREE-äge® Insecticide is a Restricted Use Pesticide and must only be sold to and used by a state certified applicator or by persons under their direct supervision.  TREE-äge® is a registered trademark of Arborjet, Inc.