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Hemlock Woolly Adelgid Infestation
Light infestation of HWA, 15 July 2008, Saco, ME
Hemlock woolly adelgids secrete a waxy material from pores covering their bodies. The material is wool-like in appearance, and is perhaps the most recognizable feature of this insect. HWA are covered with wool from their 2nd instar through the adult stage. The wool-like secretions of the hemlock woolly adelgid are visible throughout most of the year, and are generally between 1/16th and 1/8th inch across. The woolly masses increase in size as each generation matures. In late summer and early fall they can be hard to see because the adelgids are not producing wool, they are aestivating. Heavy rains during aestivation can wash off wool from previous generations. Aestivating nymphs have only a slight halo of wool (see below) and are not generally visible with the naked eye. The overwintering generation resumes feeding and wool production in Mid to Late October in southern Maine. The adult lays her eggs behind her in the wool, making the ovisacs (wool) appear very puffy.
Heavy infestation of HWA, 24 May 2007, Kittery, ME
Hemlock woolly adelgids secrete a waxy material from pores covering their bodies. The material is wool-like in appearance, and is perhaps the most recognizable feature of this insect. HWA are covered with wool from their 2nd instar through the adult stage. The wool-like secretions of the hemlock woolly adelgid are visible throughout most of the year, and are generally between 1/16th and 1/8th inch across. The woolly masses increase in size as each generation matures. In late summer and early fall they can be hard to see because the adelgids are not producing wool, they are aestivating. Heavy rains during aestivation can wash off wool from previous generations. Aestivating nymphs have only a slight halo of wool (see below) and are not generally visible with the naked eye. The overwintering generation resumes feeding and wool production in Mid to Late October in southern Maine. The adult lays her eggs behind her in the wool, making the ovisacs (wool) appear very puffy.