BANGOR DAILY NEWS | Friday | October 21, 2011 | 11
Christmas Continued from Page 10
tion. Like its balsam and hemlock cousins, the female Eastern spruce gall adelgid spends the winter attached to a host tree’s twigs, then covers itself with a white, waxy material. A maturing female adelgid lays her eggs inside this material, the hatching nymphs feed on the adjacent twig material, and a swelling (or gout) forms at the affected site. According to Donahue, tree growers can use specific pesticides to control the Eastern spruce gall adelgid in early May. Dormant oil can be applied at appropriate times, too. • Cooley spruce gall adelgid . Infesting Douglas fir and blue spruce, this adelgid also causes galls to develop on host trees, ruining their aesthetic appeal and causing needles to turn yellow and twist. Mechanical shearing removes unsightly galls, and tree
The Cooley spruce gall adelgid causes galls to develop on blue spruce and Douglas fir trees. The galls ruins a tree’s aesthetic appeal.
Elongate hemlock scale, a Japanese import, feeds on hemlock needles and gradually turns them yellow. Tree limbs die; so does the host tree. This insect pest appeared in southern Maine aboard landscape trees imported from southern New England, where elongate hemlock scale causes major headaches for Christmas tree growers.
growers can spray infested tree with specific pesticides in the spring, before the spruce buds open. Donahue indicated that growers can help stop this adelgid from
spreading by planting blue spruce and Douglas fir some distance apart.
• Spruce spider mites. These exceedingly small insects lay eggs that hatch each spring. “The six-
legged larvae feed on foliage and can reach maturity within a week,” an MFS brochure reports. Feeding larvae cause “tiny chlorotic flecks” to appear on needles, “and the foliage appears mottled,” the brochure indicates. “Damaged needles may dry up and drop off. Christmas trees may be severely damaged by this mite.” According to Donahue, extremely dry weather spurs spruce spider-mite growth, but natural predators often keep this insect pest under control. Tree growers can treat affected trees with Kelthane or Lorsban. • White pine weevil. Landowners who raise white pines are familiar with this weevil, which the MFS calls “the most serious economic insect pest of white pine.” The weevil attacks only a tree’s leaders (the highest branches) and kills them as the weevil’s grubs tunnel beneath the bark. If not removed, dead leaders can stunt a white pine’s growth. A weevil-damaged pine will create a new See INSECTS, Page 12
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