Tag Archives: insects

Watching out for the Emerald Ash Borer & other Invasives

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Large purple plastic triangular boxes illustrate monitoring activity
Large purple plastic triangular boxes illustrate monitoring activity

by Brad Withrow-Robinson, OSU Forestry & Natural Resources Extension, Benton, Linn and Polk Counties and Wyatt Williams, ODF Invasive Species Specialist

A large purple box hanging in the trees along Airlie Road last year caught my attention at 55 mph. Pulling over I recognized it as a monitoring trap for one of the current invasive species threatening Oregon’s woodlands. Luckily ODF and others are watching out.

The emerald ash borer (EAB), an invasive insect from Asia, has killed an estimated 100 million trees and caused more than $3.5 billion dollars’ worth of damage and property value losses in the eastern U.S. since its arrival in the 1990’s. All 16 North American ash species are threatened with extinction, including our native Oregon ash. The furthest west population yet detected is in Boulder, Colorado – a day’s drive or so from Oregon in a motor home. Originally introduced to the U.S. via wood packaging material, it is now spread across the continent in infested firewood.

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Yellowjackets

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by Chal Landgren, OSU Extension Christmas Tree Specialist

Anyway it is spelled- Yellowjacket, Yellow Jacket or Yellow-Jacket, these insects are feared and hated not only by picnickers, but by many working in the woods, and in Christmas trees.  For Christmas tree growers they can inflict physical and economic pain, since they are unwanted hitchhikers in many shipping destinations.

First some biology- These are not honeybees. Rather, two predatory insects in the genus Vespula, whose common names are the Western Yellowjacket and German Yellowjacket. The Western

Comparison of queens. Photo courtesy ODA
Comparison of queens. Photo courtesy ODA

Yellowjacket (V. pensylvanica) is a common native.  Yes, they are predators, but also scavengers, which makes them a pest at summer BBQs and picnics.  The German yellowjacket (V. germanica)  is an uncommon non-native species (not wanted in Mexico).  Both these insects feed on other insects as well as nectar, honeydew and fruit.

Queens will overwinter in protected locations above or below ground and emerge in May. After the queen emerges she will begin her colony which eventually can include hundreds to thousands of workers. Fertilized queens will emerge again in October or November. Males (stingless) begin to emerge in large numbers in late July. Continue reading →

The boom-and-bust life of defoliating insects

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By Amy Grotta, OSU Forestry & Natural Resources Extension – Columbia, Washington & Yamhill Counties

It is shaping up to be another exciting year in forest health here in northwest Oregon. Fortunately, neither of the two defoliating insects currently on the scene are serious threats to forest or human health, but they are certainly causing a stir.

Right now, Columbia County is in the midst of the largest documented western tent caterpillar outbreak that Oregon has seen in two decades, according to the Oregon Department of Forestry. I first noticed a few tent caterpillar clusters on one site in the area two years ago. Last summer, our Extension office received many calls as the caterpillar population built up.  Aerial surveys done a few weeks ago show that at least 13,000 acres are affected in the county this year.

Map and aerial view showing extent of western tent caterpillar defoliation, early June. Affected areas are brown in the photo. Source: Oregon Department of Forestry
Map and aerial view showing extent of western tent caterpillar defoliation, early June. Affected areas are brown in the photo. Source: Oregon Department of Forestry

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Flea beetles skeletonize red alder leaves

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Submitted by Glenn Ahrens, OSU Extension Forester, Clackamas, Marion & Hood River Counties

Alder flea beetles are particularly active this summer as they go about their business of skeletonizing leaves on red alder trees. I have seen this come and go over the years, and generally flea beetles are not a serious threat. Flea beetle flare-ups in the forest usually run their course after 2-3 years, after which their population crashes – similar to western tent caterpillar infestations. Healthy alder trees with good vigor are usually not seriously affected. Stressed alder trees – particularly those in dense thickets – may die after 2-3 consecutive years of flea beetle infestation. If you like your red alder trees and want to promote “good vigor” the best way is to 1) avoid growing alder on poor alder sites and 2) keep trees well-spaced to ensure large healthy crowns.

What’s big, black and white, and not a pest?

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Summer must be coming to an end. I say that not because the kids are going back to school or the tomatoes are (finally) starting to turn red, but because today I got my first call of the year about a strange and striking looking insect.

This is a banded alder borer. It is a native wood boring insect, but it is not considered a forest pest because it generally infests dead or downed wood (people often find them on their firewood piles). This insect is often confused with the Asian Longhorn Beetle, which is one of the nation’s most un-wanted invasive pests. If you find a large, black and white insect with long antennae, chances are it’s the banded alder borer (the good guy), but to be sure, look for a white head with a large black dot on it. See the photo above.

I am not sure about the banded alder borer’s life history, but I think the adults must be most active in August and September because that’s when the calls and emails start to come in.