The adult moth is approximately 1 inch in length. Forewings are pink with a yellow colored band in the center. After adult moths become active in the spring, yellow eggs are laid on the underside of leaves over a very extended period of time. When caterpillars are mature, they can be up to an inch and a half in length with reddish heads and a pale green body that has 7 greenish-black stripes running lengthwise. On the thorax of the caterpillar (second thoracic segment), two black horns or projections are present. These horns are longer than the additional, smaller black spines that are found on the rest of the body of the caterpillar. Caterpillars are often found in trees particularly in late July and early August but sometimes as late as September in New England. The pupal stage overwinters in the soil. In the northeast, one generation per year is recorded. In the southern portion of its range, there are two generations per year (potentially 3) and caterpillars may be active from May to November. In those locations, oak may be defoliated twice in the same season. Historically, outbreaks of this native caterpillar have defoliated sugar and red maples in eastern Canada and the northeastern United States. Adults of this species are known as "rosy maple moths" and are hairy with beautiful combinations of yellow and pink on the wings and a yellow body; they are often admired for their beauty. Adult moths will play dead when handled.
Foliage of maples may be partially or completely defoliated. Often, lower branches of its hosts are fed upon first. Smaller trees may occasionally be completely defoliated. Leaves are typically fed upon down to the midrib. Caterpillars feed in groups until the 3rd instar (Wagner, 2005). Occasionally oak is fed upon, particularly when it is in close proximity to maples. However, in New England, the feeding of this native insect may not be of huge concern for the overall health of the host plant, unless a population outbreak occurs.
Monitor the undersides of leaves for the clusters of yellow eggs in the spring. Look for groups of feeding caterpillars between July and September in New England. Management of this native insect may not be necessary unless the population is experiencing an outbreak year. Because there is one generation per year, otherwise healthy trees can typically withstand a single year of defoliation.
If caterpillars are found feeding in groups, remove them by hand when practical on young trees.
Green-striped mapleworm reportedly has some natural enemies, including parasitoids, but it is unknown how effective they are are reducing their population. They are noted to be mostly distasteful to bird predators, however some predation from birds does occur.
Abamectin (NL)
Acephate (NL)
Acetamiprid (L)
Azadirachtin (NL)
Bacillus thuringiensis subsp. kurstaki (NL)
Beauveria bassiana (NL)
Bifenthrin (NL)
Carbaryl (L)
Chlorantraniliprole (NL)
Chlorpyrifos (N)
Chromobacerium subtsugae (NL)
Cyantraniliprole (NL)
Flonicamid + cyclaniliprole (N)
Horticultural oil (L)
Indoxacarb (L)
Insecticidal soap (NL)
Malathion (L)
Methoxyfenozide (NL)
Neem oil (NL)
Pyrethrin+sulfur (NL)
Spinosad (NL)
Tebufenozide (NL)
Active ingredients that may be applied systemically include: acetamiprid (injection), chlorantraniliprole (soil drench), cyantraniliprole (soil drench, soil injection), and neem oil (soil drench).
When used in nursery settings, chlorpyrifos is for quarantine use only.
Make insecticide applications after bloom to protect pollinators. Applications at times of the day and temperatures when pollinators are less likely to be active can also reduce the risk of impacting their populations.
Note: Beginning July 1, 2022, neonicotinoid insecticides are classified as state restricted use for use on tree and shrub insect pests in Massachusetts. For more information, visit the MA Department of Agricultural Resources Pesticide Program.
