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Matsucoccus gallicolus

Ponderosa pine twig gall scale, Matsucoccus bisetosus, a related species. In search of M. gallicolus photo. Photo: Donald Owen, California Department of Forestry and Fire Protection, Bugwood.
Scientific Name: 
Matsucoccus gallicolus
Common Name: 
Pine Twig Gall Scale
Growing Degree Days (GDD's): 
None available at this time.
Host Plant(s) Common Name (Scientific Name): 
Loblolly pine (Pinus taeda)
Pitch pine (Pinus rigida) *Preferred host.
Ponderosa pine (Pinus ponderosa)
Red pine (Pinus resinosa)
Shortleaf pine (Pinus echinata)
Spruce pine (Pinus glabra)
Table mountain pine (Pinus pungens)
Virginia pine (Pinus virginiana)
Insect Description: 

There are at least 15 species of scale insects from the family Margarodidae (also called ground pearls) in the genus Matsucoccus found in North America - and all except one feeds on various pine tree (Pinus) species. The pine twig gall scale (M. gallicolis) may be particularly damaging to Pinus rigida or pitch pine. The pine twig gall scale occurs on the new growth of the host plant, causing gall-like swellings to form. A single generation occurs per year. The pine twig gall scale overwinters as an egg beneath bark scales which hatch in the spring (late April in Connecticut; Parr, 1939) with the development of new needle growth (when needles are 1-3 inches long). Yellow, first instar crawlers will locate the new growth and insert piercing-sucking mouthparts in the shoot to feed. A tiny pit develops where the insect has been feeding. Eventually, the crawler molts into the second instar, which is shaped like a cyst (round and legless) and the host plant grows a gall-like swelling around the insect with only a tiny opening. By late July, the scale insect has matured and an adult female emerges from the gall-like swelling via the tiny opening. Adult females are tiny, approximately 2.4-4.5 mm in length and 1-2.7 mm wide. Once on the trunk or main branches, the adult females lay up to 150-500 lemon yellow colored, tiny eggs in an ovisac beneath bark scales (Parr, 1939). No adult males are currently known for this species, however second and third instar males have been described. This species is in the same genus as the red pine scale (M. resinosae), a serious pest of red pine (Pinus resinosa) particularly in southern New England. The red pine scale has killed many planted red pine.

Damage to Host: 

The initial sign of an infestation by the pine twig gall scale may be that the needles of the host turn brown at the tips of branches. Terminals and new growth of pitch pine are most impacted. Other hosts may become infested if grown ornamentally. Heavily infested needles can be easily pulled from the stem in clumps. Severe infestations weaken their host plants, causing branch dieback and potentially tree death. In some historical accounts, trees were said to never reach timber size (Aughanbaugh,1949) Twigs killed by this insect may be covered in black spots, if viewed with magnification. 


Viewing these scales may require careful dissection of the host plant twig bark (under magnification) in order to find the scales themselves or their cast (shed) skins within gall-like pits. 

Cultural Management: 

Presumably, on ornamental specimens, heavily infested branches can be pruned out and destroyed after needle elongation in the spring and initial scale feeding, but prior to the development of the adult female scales in July. If adult females are present and move to the trunk and branches to lay their eggs, pruning and removal of symptomatic branches will not help reduce the potential for overwintering eggs of this species of scale.

Natural Enemies & Biological Control: 

Two species of minute pirate bugs, Elatophilus inimicus and Elatophilus pinophilus, are known to feed on the pine twig gall scale (ScaleNet). A rarely collected species of plant bug, Largidea davisi, is also thought to be a predator of the pine twig gall scale (Wheeler, 2004). This species is known only to pitch pine found in pine barrens of parts of Massachusetts, including Cape Cod. Additionally, Largidea davisi has been collected from Connecticut, Maine, New Hampshire, New Jersey, Pennsylvania, Rhode Island, and New York.

Chemical Management: 

Abamectin (NL)

Acephate (NL)

Acetamprid (L)

Azadirachtin (NL)

Buprofezin (NL)

Carbaryl (L)

Chlorpyrifos (N)

Clothianidin (NL)

Cyantraniliprole (NL)

Cyfluthrin (NL)

Dinotefuran (NL)

Flonicamid+cyclaniliprole (N) (listed as effective against soft scales)

Gamma-cyhalothrin (L)

Horticultural oil (L)

Imidacloprid (L)

Insecticidal soap (NL)

Lambda-cyhalothrin (L)

Neem oil (NL)

Pyrethrin + sulfur (NL)

Pyriproxyfen (L)

Spinetoram + sulfoxaflor (N)


Active ingredients that may be applied systemically include: abamectin (injection), acephate (injection), acetamprid (injection), azadirachtin (injection, soil drench), clothianidin (soil drench), cyantraniliprole (soil drench, soil injection), dinotefuran (soil drench), imidacloprid (soil drench), and neem oil (soil drench).

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: .