Matsucoccus gallicolus

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.