Types of Garden Enemies
(Chermes abietis). Very common in home plantings of Norway spruce, also on white, black, and Engelmann's spruce. Greenish aphids winter around the bud scales and lay eggs on twigs in spring. The nymphs feed on new growth causing leaf bases to enlarge into bulb-like hollows, up to 50 of these cells being joined together to form a pineapple-shaped gall at the base of a twig and usually 2 or 3 galls together on a branch. New galls, up to an inch long, are green with the closed mouth of each cell marked with a red or purple line and each containing a dozen or so aphids. The cells open in midsummer (early August in New Jersey), releasing the aphids to lay eggs on the needles. These hatch in a few days into the overwintering nymphs. The galls turn brown after opening, and branches frequently die back.

Control. On small trees cut out the galls before they open if it is possible to do this without too much disfigurement. Spray in spring just before new growth starts with a miscible oil, 1 to 30 dilution, making sure the temperature will stay above 45 F. until the spray has dried, or with nicotine sulfate and soap, or with lindane.

{Chermes cooleyi). This species causes large terminal galls, 1 to 2 inches long, on Colorado blue spruce and also on Sitka and Engelmann's spruce. Aphids winter near terminal buds and lay eggs in spring, the nymphs producing the gall which is an enlargement of the stem together with thickening of the needles. The green changes to straw color after the cells open in July. The aphids released then acquire wings and migrate to Douglas-fir, laying eggs in nests of white wax, the nymphs remaining on fir needles until spring, when eggs are laid there. From that generation winged individuals migrate back to spruce, the complete life cycle taking 2 years.

Control. Unless trees are too large it is easy to cut off terminal galls before they open. Oil spraying should be done with caution, for it takes bloom off the needles. Spraying with lindane or nicotine is preferable.

(Colopha ulmicola). Green elevations with red tips, looking like cocks' combs, are filled with green or brown aphids which drip honeydew from the leaves onto walks and parked automobiles. There is no practical control.

(Macrosiphum rudbeckiae). Bright red lice with long legs stand out from goldenglow stems, crowd between larkspur buds, and cause delphinium leaves to cup downward.

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