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Pinapple Gall Adelgid



P_pnplegladelgid

Pinapple Gall Adelgid

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Caused By:-     Two Species of adelgids

Description

Three Pineapple Galls developing on Norway Spruce. Caused by Adelges abietis.
Most spruce trees are attacked by one of two species of gall forming adelgids, which are related to aphids. The pineapple or pseudocone gall adelgid Adelges abietis and the Cooley spruce gall adelgid Adelges cooleyi both of which feeds on the plant sap and in doing so they induce gall formation which stunts, disfigures and can eventually kill the twig. They are small about 1.5mm and not easily seen. The shape, size and position of the induced galls on the twig aid in identifying the species involved. Heavy infestations can destroy the natural beauty of the tree and continuous infestations can seriously weaken trees and make them more susceptible to attack by other organisms. There is also the possibility of virus and disease transmission.
When galls are first produced, they are green, soft and made up of many individual compartments which are inhabited by the developing adelgids. They are often mistaken for the cones of the tree.
The adelgids overwinter as nymphs on twigs near the terminal buds and resume feeding in the spring. The adelgids mature about early May and produce a conspicuous, waxy cover under which they lay their eggs. They die shortly afterward, leaving the eggs protected beneath their bodies, which resemble a white, cottony twigs. The galls mature by midsummer when the cells open and the adelgids emerge. The eggs hatch in about a week, and the young insects begin to feed on the buds. Continued feeding induces abnormal growth or galls within which the insect lives and grows. Galls protect the adelgid from most insecticide sprays. The adelgids and galls mature in midsummer. The galls split and the mature adelgids emerge, develop wings, fly to the needles of the same or some other spruce and lay eggs at the base of the new growth. The eggs soon hatch and the immature forms that emerge will feed until the onset of cold weather, overwinter at the needle bases and then resume their life cycle the following spring. The empty galls soon dry, become brittle and turn dark brown.
Adelged abietis feeding causes the formation of pineapple-like galls about 10-25mm long at the base of twigs. Twig growth is normal when the gall is still green. The twig dies after the gall matures.
Adelges cooleyi produces elongated, often curved, galls about 25-75mm inches long that usually involve the entire twig. The Cooley spruce gall adelgid will frequently use Douglas fir, if present, as an alternate host. Adults may migrate to Douglas fir in late summer and lay eggs. These eggs hatch and the immature forms pass the winter there. In the spring they resume feeding, mature and lay eggs. These hatch and develop into adults that may remain on the Douglas fir or fly back to spruce to lay eggs for the next over-wintering generation. Galls are not produced on Douglas fir, but partial needle fall may occur.
See also these other Galls ACER GALL MITES, ACORN GALL MITES, AZELAE GALL, BEECH GALL MIDGE, BLACKCURRANT GALL MIDGE, BROOM GALL MIDGE, CAMELLIA GALL, CROWN GALL, EUONOMUS GALL, FELT GALL MITES, FORSYTHIA GALL, GALLS, GALL WASP, GLEDITSIA POD GALL MIDGE, HEMEROCALLIS GALL MIDGE, HAWTHORN BUTTON TOP GALL MIDGE, KNOPPER GALL OF ACORNS, LEAFY GALL, LIME NAIL GALL MITE, OAK GALL WASP, PEAR LEAF BLISTER MITE, PLUM GALL MIDGE, ROBINS PINCUSHION, TURNIP GALL WEEVIL, VINE ERINOSE GALL MITE, VIOLET GALL MIDGE, WILLOW BEAN GALL SAWFLY.


Control

Although the old galls can be unsightly this pest has little lasting impact on mature trees. On small trees galled shoot tips can be cut off, but generally this is a pest that can be tolerated.
Hand pick green galls when first noted before August and destroy. Use horticultural oil in mid- to late spring just before buds begin to break. Use horticultural oil, insecticidal soap, or insecticides in mid to late summer after galls have opened but before adelgids move to alternate hosts.
Glaucous (bluish blush) trees will turn dark green temporarily when sprayed with oil and the natural bloom may not return for one to two years. Some sensitive species may suffer from phytotoxicity. Spruce and Douglas fir may show a sensitivity to horticultural oils.
Some spruce varieties are resistant to these pests and could be used to avoid these adelgids

P_pnplegladelgid P_pnplegladelgid[2] P_pnplegladelgid[3] P_pnplegladelgid[4]

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