insects Archives

Mowing for Monarchs

Most homeowners rev up the mower when the grass loses its buzz-cut look. But how does Scenic Hudson decide when to mow the meadows in our parks and preserves? “It’s a balancing act,” says Land Stewardship Coordinator Dan Smith. “Whenever you mow, you’re benefiting something and hurting something else.”

Pollinators on Joe Pye Weed, aka Queen of the Meadow (Photo: Jo-Anne Asuncion)

Mowing cuts back trees and shrubs that, if allowed free rein, could eventually replace the meadow with forest. And it can temporarily suppress the spread of invasive species that crowd out native plants. But mowing also can eliminate the blooming wildflowers and grasses that pollinators like bees and butterflies (including monarchs) rely on for nectar, as well as the winter shelter that other species need.

Deciding when to mow depends on the chief objective. Many of the meadows in our parks are too small to support breeding grassland birds. Still, when possible, Scenic Hudson holds off mowing at least until July 15. “This gives any birds that may be breeding in a field the best chance to fledge their young,” says Smith.

Monarch butterflies on wildflowers from Seed Song Farm (Photo: Matthew Fass)

More often, Scenic Hudson’s meadow management focuses on sustaining habitat and nectar-producing plants for pollinators. “They’re a little less picky about size,” Smith says. To maximize the meadows’ potential for attracting pollinators, mowing is held off even longer, until October 1. “At that point, there are not a lot of nectar sources remaining,” he explains. Likewise, monarchs that have grown from caterpillars to butterflies on our preserves’ milkweed plants “are mostly on their way south,” undertaking their annual migration to Mexico.

One-third rule of thumb

The general rule of thumb is to mow one-third of a field each year, leaving plenty of nectar for pollinators and coverage for the winter. “But in some of our meadows woody vegetation grows so fast we need to mow more than that to maintain them. It’s one of the things I personally struggle with the most,” Smith says. Adding to his struggle, meadows filled with harmful and especially fast-spreading invasives like black swallow-wort (which closely resembles milkweed but is toxic to monarchs) require monthly mowing.

Monarch caterpillar on common milkweed at Poets’ Walk Park. (Photo: Dan Smith)

In addition to determining when to mow, it’s important to know how much to lop off. “It’s always good to leave some height,” Smith says. Mowers contracted by Scenic Hudson are advised to leave about 10 inches, which destroys the seed-producing parts of most invasive species while keeping intact many parts of plants where pollinators have laid eggs or larvae may overwinter.

Smith’s overall assessment of Scenic Hudson’s mowing strategy: “Our data show it’s working for the most part, but we’re always open to tweaking our approach.”

Tackling Ticks

Rick Ostfeld holding a white-footed mouse

Enjoying outdoor exercise helps boost our immune system and relieve stress, which has never been more important. But while a walk in the woods may keep you healthy on one hand, it also makes you a prime candidate for contracting Lyme disease.

Tick-borne illnesses have doubled since 2004, and New York ranks second only to Pennsylvania in the number of cases, with the lion’s share occurring in the Hudson Valley. Fortunately, Millbrook’s Cary Institute of Ecosystem Studies is at the forefront of efforts to halt this scourge.

In 2016, the institute partnered with Bard College, the U.S. Centers for Disease Control and Prevention, NYS Department of Health, and Dutchess County Department of Behavioral and Community Health to kick off the Tick Project. Headed by Cary disease ecologist Richard Ostfeld and Bard biologist Felicia Keesing, the five-year study will determine if a neighborhood-based method of tick prevention can prove effective and safe — for people, pets and the environment.

Rick Ostfeld holding a chipmunk. (Photo: ©Cary Institute of Ecosystem Studies / Robin Moore)

Ongoing in 24 Dutchess County neighborhoods, the study focuses on testing the effectiveness of two pesticide-free methods to reduce tick populations. One, the Tick Control System, consists of a small box that attracts mice and chipmunks, both primarily responsible for infecting ticks with Lyme bacteria. Rodents entering the box receive a low dose of the same chemical in your dog or cat’s tick-killing collar. In the second method, a naturally occurring fungus that kills ticks is applied to vegetation. The two methods are being tested separately and in tandem.

To date, researchers have completed more than 24,000 surveys in the neighborhoods. At the end of 2020, the partners began analyzing and synthesizing these and all remaining results. Eventually, the partners hope to recommend strategies for municipalities, community groups, and others to take a bite out of Lyme disease.

In the meantime, enjoy this compelling video presentation by Dr. Ostfeld that contains info about the Tick Project and Lyme disease in general.

Lantern Fly

Now, more than ever, be on the lookout for spotted lantern flies. Sightings of these EXTREMELY harmful insects, native to Asia, have just been confirmed in Manhattan’s Riverside Park as well as across the Hudson in Secaucus, N.J. — bringing them perilously close to the Hudson Valley. Last year, they also were discovered in three upstate counties and on Long Island.

The flies feed on the sap of — and can wreak great havoc on — more than 70 plant species. Favorite food sources include apple trees and grape vines, whose yields add $358 million to New York’s economy each year. The flies also secrete an unpleasant, sticky substance (known as honeydew) that can get on the hair and clothes of those trying to enjoy outdoor recreation.

Warmer temperatures encourage the flies’ northward migration, and humans facilitate their move — the bugs lay eggs on firewood and other objects left outdoors and then transported elsewhere. While the state Department of Agriculture & Markets has issued a quarantine on certain goods from areas in Delaware, New Jersey, Pennsylvania and Virginia most hard-hit by this infestation, the recent sightings show it’s not foolproof —and that your help is urgently needed to halt the insects’ spread into our region.

This fact sheet offers tips for identifying spotted lantern flies and what you can do to keep these pests in check.

Solar Buzz

Underhill solar farm in Poughkeepsie, which went on line in 2019, was one of New York’s first solar arrays developed expressly to include habitat for bees and other pollinator species — a win-win. It not only produces clean energy, weaning us off fossil fuels that contribute to climate change, but supports insects critical for making the valley’s crops — and the region’s agricultural economy — continue to grow. A third of the world’s food depends on pollinators, whose numbers have been declining alarmingly. In the U.S., honeybees alone contribute nearly $20 billion to the value of U.S. crop production, including Hudson Valley food favorites like apples, cherries and blueberries.