In 2021, more than 5.8 million acres of trees were killed and 5.7 million acres suffered damage from pests and diseases in the United States.
Pest Prevention Fall and winter are ideal times to start protecting trees against spring infestations By Millicent Skiles
"By the fall you’re worn out. But you have to wake up for a few minutes,” says Chip Doolittle, president of ArborSystems, a provider of injection solutions to treat tree pests. “Just be- fore you take off on that vacation, you need to be planning what you’re going to be doing next year.” THE NEED FOR VIGILANCE In 2021, more than 5.8 million acres of trees were killed and 5.7 million acres suffered damage from pests and diseas- es in the United States, according to the U.S. Department of Agriculture. That same year, a study in the journal Frontiers in Forests and Global Change discovered that forests damaged by insects and disease were reducing the carbon sequestration potential of forests across the country by about 50 million tons of carbon dioxide each year, about 10 million cars’ worth of emissions. Every tree has its nemesis, generally categorized as arthropods (insects and spiders,) vertebrates (animals,) weeds, pathogens, and nematodes. For the most part, trees have spent hundreds of millions of years evolving a system
of checks and balances to stave off attacks from pests. Yet, introduce a foreign pest to the area or plant a non-native tree and all bets are off. As arborists look toward spring, it’s hard to make predictions on how pests will behave. “We don’t know what to expect, but it’s coming into our ports right now,” says Rob Gorden, director of urban forestry and business development with Arbor- Jet, Inc., a provider of tree injections and pneumatic soil excavation tools. He points to the emerald ash borer ( Agrilus planipennis ), whose larvae feed under the bark of ash trees, dis- rupting vascular systems and choking off water supplies. Native to Asia, it likely arrived in the United States in wood packing materials in 2002. “While they may target weaker trees in Asia, here they attack healthy trees,” Gorden says. Like many pests, the emerald ash borer keeps a low profile, with new infesta- tions avoiding detection for up to three years. Aer frantically feeding and
Emerald ash borer, Dutch elm disease, sudden oak death. The mere mention of these insects, fungi, and diseases is likely to keep any arborist up at night. Whether they bore, suck, or chew, these pests can wreak havoc on entire forests and tree communities. In Massachusetts, keeping watch for invasive pests is a full-time job. When the state’s 3.2 million acres of forests enter their dormant season, four for- esters take to the sky, hop on boats, and creep on foot to meticulously track the spread of beech leaf disease (likely caused by Litylenchus crenatae , a foliar nematode) and spongy moths ( Lymantria dispar ). “They’re out there with their binoc- ulars all winter,” says Nicole Keleher, director of the Massachusetts Depart- ment of Conservation and Recreation’s forest health program. “It’s complex, there’s a lot going on." Aer a busy growing season, it might be tempting for tree care companies to take a break as fall and winter ap- proaches. But for those with their eye on the future, they know a new cycle of work is about to begin.
Like many pests, the emerald ash borer keeps a low profile, with new infestations avoiding detection for up to three years.
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