Emerald ash borers emerge

FRITZ MAYER
Posted 5/29/19

REGION — It’s spring, and that means insects are active again. The emerald ash borer (EAB) is now emerging from tiny holes in the ash trees to lay eggs on leaves and bark. When the eggs …

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Emerald ash borers emerge

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REGION — It’s spring, and that means insects are active again. The emerald ash borer (EAB) is now emerging from tiny holes in the ash trees to lay eggs on leaves and bark. When the eggs hatch, the larvae tunnel into the tree and eat the outermost layer of the sapwood beneath the bark. That’s what ultimately kills the tree, if the lifecycle is not interrupted by various available pesticides.

EAB first appeared in southern Michigan in 2002, most likely in infected ash wood. The bright green insects have since spread to 35 states from Texas to Maine. According to the U.S. Forest Service (USFS), the bugs have killed more than 70 million trees since then and cost states, municipalities and landowners millions of dollars to try to control.

Sen. Chuck Schumer noted that most baseball bats in the U.S. and New York State are made out of ash wood, so according to a press release, “Schumer called for a major infusion of federal funding responsible for efforts to research and help curb the spread of rampant invasive species like the EAB. Schumer said that not only would robustly investing the extermination and control of the EAB be critical to protecting the state economy, but [it] would also help keep ash-made baseball bats affordable, protecting the future of one of America’s favorite pastimes: baseball.”

The USFS has been studying the EAB and has learned quite a bit about their life cycles. “We found that mated females flew further than unmated females and males. The average distance flown by mated females was about 3 km, (1.5 miles) however, 20% flew >10 km and 1% flew >20 km. These findings demonstrate one of the reasons that eradication of EAB in North America has been unsuccessful.

“In forested areas, EAB tend to attack upper trunks and limbs of larger trees, gradually weakening them by destroying phloem. This severely weakens the trees, facilitating mass attack by EAB on the main trunks, resulting in tree death. It has been estimated that this process requires about five years when EAB populations have reached outbreak levels. Some trees die more quickly depending on age, health, species of ash and EAB population density in the area.

“The best early sign of EAB infestation in an area is woodpeckers feeding on the main upper limbs and large branches of ash trees. Woodpeckers are important predators of EAB living under the bark of ash trees. Evidence of woodpecker feeding is readily observed because they remove patches of bark from trunks while scavenging, resulting in light-colored (orange-pink) patches of bark along the usual grey weathered ash trunks. Over the years of EAB attack, woodpecker feeding can be observed lower and lower on the ash trunks.”

A shrinking tree canopy can also be a sign if tree infestation. If a tree loses half of its canopy, it’s probably too far gone to be saved. There are a number of chemicals that can be used for treating and EAB infestation, but the bugs must be discovered early on before the infestation is too heavy. And even then, the treatments must be carried out over several years, and they are expensive. Visit www.bit.ly/TRReabfacts for more information.

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