Lauterbach: Emerald Ash borers are bad and they're heading west

Special to The Idaho StatesmanOctober 18, 2013 

The Emerald Ash borer and the holes they make.

The devastating Emerald Ash borer is migrating closer to us. This metallic-colored beetle has ravaged forests and landscape trees in the East and Midwest and spread very quickly since its first appearance in this country in June 2002.

The insect crossed the Missisippi into Kansas, then earlier this month it was found in Boulder County, Colo. Transporting of ash trees that might harbor this pest has been controlled, but it's thought the insect has been spread in firewood.

Urban forestry officials are scrambling to try to protect their valuable shade trees in cities and towns. It is not here yet, according to Debbie Cook, an arborist with Boise Park & Recreation.

Our ash trees are already under attack by the Lilac Ash borer, the parent a clear-wing moth that's transient from tree to tree. It cannot be controlled with systemic pesticides, but the Emerald Ash borer can be controlled with systemic treatment if it hasn't already doomed the tree.

Symptoms of the marauding Emerald Ash borer are sparse leaves on highest branches, new sprouts on the lower trunk or branches, vertical splits in the bark, D-shaped exit holes about one-eighth inch wide, and increased woodpecker or flicker activity.

The adult beetle is a dark metallic green, about one-half-inch long, and one-eighth-inch long. It can fly, but generally it and many other insects "migrate" in firewood carried from one state to another. There's no law against moving firewood, but please do not import it or buy it from sources obtained out of state.


If you have special pumpkins (the eating kind, not jack o'lanterns) and/or squash, consider giving some to friends. Those are very nice, appreciated gifts.

Incidentally, master gardener Bev Williams says marigolds planted around and near her squash effectively repelled squash bugs last summer.


The Idaho Horticulture Society has opened a period for grant applications for projects that create, promote or further "interest in horticulture, gardening, civic beautification, and natural resource conservation" in the state of Idaho and Malheur County, Oregon.

The grant application form and guidelines may be reviewed and downloaded from Deadline for applications is Nov. 22. All correspondence, including questions, should be directed to the IHS grant coordinator at


Early autumn is a great time to plant fruit trees, shrubs and vines, letting them settle in and begin to establish new roots before harsher cold of winter. If you do plant new trees or shrubs this fall, use a bark mulch to insulate those tender new roots from cold temperatures.

In spring, you can sit back and just watch new leaves emerge. If you can get trees in containers, all the better, because you'll have a year's advantage on getting to fruiting stage.

Do your homework online or in paper catalogs to determine whether you'll need a pollinator and what it would be, then shop locally. Locally-owned nurseries such as Garden Center West, Franz Witte, Far West, Edwards Greenhouse, Cloverdale Nursery, Barber Hills, Greenhurst, Victory Greens, and The Nursery, for instance, carry trees, shrubs and vines suitable for our area. Also, consider the Fruitland Nursery in Fruitland for trees adapted to our climate.

Remember, semi-dwarf trees bear fruit on younger trees than standard trees, and dwarf trees bear fruit on trees even when trees are younger than those semi-dwarf bearing trees.

If you situate your fruit tree on the north side of your house (not shaded), it may blossom later than on the warmer southern exposure, yielding viable fruit instead of frost-killed blossoms.

Send garden questions to or Gardening, The Statesman, P.O. Box 40, Boise, ID 83707.

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