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Homadaula anisocentra

Mimosa webworm feeding damage and webbing. Photo: Nick Brazee
Scientific Name: 
Homadaula anisocentra
Common Name: 
Mimosa Webworm
Growing Degree Days (GDD's): 
900-1200 GDD's; 1000–1600 GDD's; 1800-2100 GDD's, Base 50F, March 1st Start Date (Source: Cornell Cooperative Extension; Robert Childs, UMass Extension.) Conflicting ranges reported depending upon the source.
Host Plant(s) Common Name (Scientific Name): 
Mimosa (Mimosa spp.)
Honeylocust (Gleditsia spp.)
Insect Description: 

The mimosa webworm was first detected in the United States in 1940 in Washington, D.C. on its common namesake host plant. Originally from China, the mimosa webworm is primarily a pest of honeylocust (Gleditsia triacanthos; including thornless cultivars). This insect is found throughout the eastern and midwestern states and California. In the warmer parts of its range in the United States, it has historically heavily attacked mimosa where it grows. Adults are moths that are silvery gray in color with wings interrupted by black dots. Moths are approximately 13 mm in size (wingspan). Fully grown larvae reach up to 16 mm long and are variable in color from gray to brown with five longitudinal white stripes. Once mature, the caterpillars move to the bark scales of their host plants and find sheltered places to pupate. They may also be found in the leaf litter beneath host plants, pupating in a cocoon. Pupae are yellowish brown, 6 mm long, and encased in a white cocoon. Adult moths may emerge in early-mid June and lay gray eggs on the leaves of their hosts that turn a rose color just prior to hatch. Eggs hatch and feeding caterpillars web together the foliage, feeding within the web for protection. Larvae may be found feeding together in groups, in which case larger and aesthetically displeasing webs may be created. If disturbed, the larvae may move quickly and can drop from the web on a line of silk. A second generation of moths may occur, with pupation happening and adults emerging by August in warmer locations. In New York and New England, it is likely that this second generation emerges in September and any offspring may be killed by cold winter temperatures. In the warmest parts of this insect's introduced range in the United States, three generations may be possible per year.

Damage to Host: 

The larvae (caterpillars) of this insect tie the foliage of their hosts together with silken strands and skeletonize the leaves. Injury to host plant leaves may be noticeable by early July in Massachusetts. Foliage can appear bronzed in color from the feeding. Webbing usually begins at the tops of trees. An entire tree may become covered in the webs created by these caterpillars. So much webbing can often make it difficult to assess the extent of the defoliation or damage caused on an individual host. 


Monitor susceptible hosts for caterpillar activity and webbing beginning in the end of June, early July. 

Cultural Management: 

Certain cultivars of honeylocust may vary in their susceptibility to this insect. Gleditsia triacanthos 'Sunburst' was highly susceptible to attack in Indiana. Cultivars such as 'Moraine', 'Shademaster', and 'Imperial' may be less susceptible - however, they are still able to be fed upon by this insect so annual monitoring may be necessary. 

Natural Enemies & Biological Control: 

The mimosa webworm has documented parasitoids that impact its populations in the United States. Up to nine parasitoids have been reported (Miller et al. 1987), however two species in particular may be of primary importance in impacting mimosa webworm populations. A study completed in Indiana found that on thornless honeylocust that were observed, average browning of the foliage per tree varied from 10.1-13.7% from the feeding activity of the first generation caterpillars and 19.7-32.5% browned foliage from the second generation of feeding caterpillars. Two hymenopteran parasitoids were found impacting the population of mimosa webworm in this study - Elasmus albizziae and Parania geniculata. Average parasitism per tree observed ranged from 9.3-15.2% in the first generation of mimosa webworm and 28.1-30.2% during the second generation, with E. albizziae having the greater impact. Authors believe that the two parasitoids may occasionally contribute to a decrease in the abundance of mimosa webworm populations (Sadof and Snyder, 2005).

Chemical Management: 

Abamectin (NL)

Acephate (NL)

Acetamiprid (L)

Azadirachtin (NL)

Bacillus thuringiensis subsp. kurstaki (NL)

Beauveria bassiana (Larvae) (NL)

Bifenthrin (larvae) (NL)

Carbaryl (L)

Chlorantraniliprole (larvae) (NL)

Chlorpyrifos (N)

Chromobacterium subtsugae (NL)

Cyantraniliprole (larvae) (NL)

Cyfluthrin (NL)

Deltamethrin (L)

Emamectin benzoate (L)

Flonicamid+cyclaniliprole (N)

Horticultural oil (eggs) (L)

Malathion (L)

Permethrin (L)

Pyrethrins+piperonyl butoxide (L)

Pyrethrin+sulfur (NL)


If a tree is already very heavily infested with webbing, it may be too late to apply an insecticide. The damage may have already occurred, and any remaining caterpillars will be very well protected within their webs.

When used in a nursery setting, chlorpyrifos is for quarantine use only.

Active ingredients that may be applied systemically include:abamectin (injection), acephate (injection), acetamiprid (injection), azadirachtin (injection, soil drench), chlorantraniliprole (soil drench), cyantraniliprole (soil drench, soil injection), and emamectin benzoate (injection).

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.

Read and follow all label instructions for safety and proper use. If this guide contradicts language on the label, follow the most up-to-date instructions on the product label. Always confirm that the site you wish to treat and the pest you wish to manage are on the label before using any pesticide. Read the full disclaimer. Active ingredients labeled "L" indicate some products containing the active ingredient are labeled for landscape uses on trees or shrubs. Active ingredients labeled "N" indicate some products containing the active ingredient are labeled for use in nurseries. Always confirm allowable uses on product labels. This active ingredient list is based on what was registered for use in Massachusetts at the time of publication. This information changes rapidly and may not be up to date. If you are viewing this information from another state, check with your local Extension Service and State Pesticide Program for local uses and regulations. Active ingredient lists were last updated: January 2024. To check current product registrations in Massachusetts, please visit: .