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Commentary: When is a pine cone not a pine cone?

Although evergreen cones are often all referred to as "pine cones," it's important to properly identify evergreen types. Special to Forum News Service

FARGO — It sounds like an interesting riddle: When is a pine cone not a pine cone? The answer: When it's growing on a spruce.

In last week's Fielding Questions, I missed a great opportunity to mention the importance of differentiating between evergreens, which resulted in spruce cones being called pine cones.

If you recall, we were discussing the heavy cone production on a transplanted spruce tree. In the original question, the cones were generically referred to as pine cones, as all cones are often nicknamed, and I replied simply used the word "cones."

The conscientious headline writers, probably thinking I was leaving something important out, headed the article with, "What do all the pine cones mean on transplanted spruce?"

A cone is the seed-bearing structure of certain plant groups, including those we commonly refer to as "evergreens," which in our region include pine, spruce, arborvitae, juniper, yew and fir.

It's important to know the difference and refer to evergreen types correctly. For example, it's a common mistake to call all evergreens "pines," because when a spruce develops needle disease, referring to it as a "pine" can cause confusion in finding solutions.

In summary, spruce have spruce cones, pines have pine cones and fir have fir cones. Thanks to all who gave me a good ribbing about the miracle of pine cones growing on spruce trees. I feel a gardening column coming on about the fascinating world of evergreen identification.

Q: We have a 10-year-old maple tree that has red bumps on the leaves. Can we leave it alone or will it die? It's had the bumps in the past but keeps thriving. — Craig and Catherine Kangas, Fargo.

A: The red or reddish-green tumor-like bumps are called maple leaf galls, caused by the feeding of tiny mites. Adult mites become active as buds open in spring. As they feed on developing leaves, hormones cause abnormal plant cell growth that encloses the mites inside a gall where they're protected. Adult mites lay eggs that hatch and feed, turn into adults and exit. Then they head for the trunk and branches to overwinter in roughened areas of bark.

Although they look scary, galls usually cause few health problems. Control is difficult once the galls form because the mites are nestled safely inside. The best time to treat an infested tree is the early spring before buds swell as adults are moving from their overwintering sites on the bark to new leaf growth. Apply horticultural oil (available at garden centers) to the bark of trunks and branches before spring bud-break to kill mites as they head for new growth after exiting their winter home in bark crevices.

Q: What are the tiny black bugs that attack alyssum? I don't know if we brought them home with us from the greenhouse or if they were here waiting. — Faye Waloch, Gwinner, N.D.

A: They're most likely flea beetles, which are small insects about 1/16 to 1/8 of an inch long. They can be present in greenhouses, but they are a common outdoor insect, attacking alyssum, cabbage, broccoli, radishes, potatoes, peppers and others. Leaves develop a shot hole appearance as the beetles eat small holes. Insecticides for control include sevin, malathion and spinosad.