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Macremphytus tarsatus

Dogwood sawfly caterpillar. (Photo: Tawny Simisky)
Scientific Name: 
Macremphytus tarsatus
Common Name: 
Dogwood Sawfly
Growing Degree Days (GDD's): 
1151–1500 GDD's, Base 50F, March 1st Start Date (Source: Cornell Cooperative Extension)
Host Plant(s) Common Name (Scientific Name): 
Dogwood (Cornus spp.)
Gray Dogwood (Cornus racemosa)
Insect Description: 

One generation occurs per year. The larvae of the dogwood sawfly overwinter in decaying wood and occasionally compromised structural timber. An overwintering "cell" is created in this soft wood. Pupation occurs in the springtime and adults can take a lengthy time to emerge, roughly between late May and July. 100+ eggs are laid in groups on the underside of leaves. Eggs hatch and the larvae feed gregariously, initially skeletonizing leaves. As the caterpillars grow in size, they are capable of eating the entire leaf with the exception of the midvein. Larval appearance varies greatly throughout instars, so much so that one might mistake them for multiple species. Early instars are translucent and yellow, but as the caterpillars grow they develop black spots (over yellow) and become covered in a white powder-like material. Larvae and their shed skins may resemble bird droppings. Full grown larvae begin to wander in search of a suitable overwintering location. Rotting wood lying on the ground is preferred for this.

Damage to Host: 

Foliage of dogwood, esp. gray dogwood (Cornus racemosa). Skeletonizes leaves at first, then eats all but the midvein.


Look for eggs laid in groups, particularly near the leaf veins of gray dogwood. Also scout for skeletonization caused by newly hatched caterpillars prior to heavier feeding. These sawfly caterpillars can cause a great amount of defoliation on their host, given their group-feeding behaviors.

Cultural Management: 

Remove groups of sawflies feeding together and drop into soapy water if necessary. Older caterpillars may be difficult to manage with insecticides, so removing them by hand (where practical) is a great first step toward management.

Natural Enemies & Biological Control: 

No effective parasites or predators are currently reported. It is suspected by some that the white, woolly coating on dogwood sawfly does not only make the larvae appear to be bird droppings, thus deterring potential avian predators, but also might play some role in deterring insect predators and parasitic wasps. The yellow and black mottled coloration that the older (wandering) caterpillars develop is also suspected to play some role in camouflaging the insect.

Chemical Management: 

Acephate (NL)

Azadirachtin (larva only) (NL)

Bifenthrin+imidacloprid (L)

Carbaryl (L)

Chlorpyrifos (N)

Cyfluthrin (larva only) (NL)

Deltamethrin (larva only) (L)

Dinotefuran (larva only) (NL)

Emamectin benzoate (L)

Flonicamid+cyclaniliprole (N)

Gamma-cyhalothrin (L)

Horticultural oil (larva only) (L)

Imidacloprid (larva only) (L)

Insecticidal soap (larva only) (NL)

Lambda-cyhalothrin (L)

Pyrethrin+sulfur (larva only) (NL)

Spinetoram+sulfoxaflor (larva only) (N)

Spinosad (larva only) (NL)


To entomologists, the term caterpillar refers to the immature or larval life stage of the Lepidoptera - butterflies and moths. However, the public and some entomologists included sometimes use this term interchangeably to refer to the immature or larval life stage of certain Hymenoptera - in particular, sawflies. 

This can cause confusion when selecting management options for pests collectively referred to as caterpillars. The larvae discussed here will mature into an adult sawfly. This means that the active ingredient Bacillus thuringiensis Kurstaki (Btk) will not be effective at managing this insect. Btk will only kill the caterpillars of moth (or butterfly) pest insects. It will not kill sawfly larvae. 

Sawfly larvae can be distinguished from moth or butterfly caterpillars by the presence of or absence of 6 or more prolegs. Some sawfly species will have 6 or more pairs of fleshy abdominal prolegs, whereas some sawfly larvae will have 0 pairs of fleshy abdominal prolegs. Caterpillars that mature into butterflies or moths will have 5 or fewer pairs of fleshy abdominal prolegs. Prolegs are soft, and found behind the hardened 3 pairs of thoracic legs on the insect. In butterfly or moth caterpillars, the prolegs will also have tiny hooks or crochets on the very bottom.

Active ingredients that may be applied systemically include: acephate (injection), azadirachtin (injection, soil drench), dinotefuran (soil drench), and imidacloprid (soil drench).

When used in nurseries, 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.

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: .