Seed Chalcid, Megastigmus atedius (Walker) (1, 11, 47)

BIOLOGY. - During late spring the female seed chalcid wasp settles on immature cones and inserts her long ovipositor down through the bone scales, depositing eggs directly into the seeds. Each larva feeds for 6 to 8 weeks, consuming the entire contents of a seed. Larvae overwinter in the seed; pupation and adult emergence occur in the
spring. Some larvae, however, may remain in a resting condition for up to 3 years. The adult wasp emerges in late May through a hole it bores in the seedcoat.

INSECT IDENTIFICATION. - Adult seed chalcid wasps are only about 3 mm long and are seldom seen. Larvae are white and legless with dark-brown to black mandibles.

DAMAGE IDENTIFICATION. - Infested seeds cannot be distinguished from sound seeds except by dissection or radiography.

IMPORTANCE. - Seed chalcid damage to eastern white pine is believed to be rare, as reports of damage have been infrequent.

Radiograph of eastern white pine seed: five seeds on left, normal; four seeds on right infested with seed chalcid. (3X)