Gathering Ground looking at solutions to destructive beetles

This article first appeared in the Washington Island Observer.
By Sheridan Ash, Gathering Ground intern.
2019 marks the second year that Gathering Ground is tending the vineyard on the Island.

Because the organization’s mission is to educate youth and adults in sustainable agriculture and to strengthen the health of the environment and community, Gathering Ground is attempting to manage the vineyard organically.

The Grounds wants to avoid the use of conventional sprays because they harm beneficial insects and can be harmful to groundwater, human health, and other animals. However, there are few organic vineyards in the Midwest; therefore, the five-acre vineyard that forms the foundation of the nonprofit is used for research rather than to produce a commercial crop.

The Midwest has specific pressures such as high humidity that causes molds and mildews, and beetles, such as the rose chafer and Japanese beetles that are difficult to manage. For this reason, Gathering Ground has recruited the help of Judy Reith, a retired director of the Madison Research Garden, board member of Wisconsin Grape Growers and an organic vineyard consultant from Baraboo, WI to aid in the undertaking.

In addition, the vineyard relies on volunteers. Pruning grape vines was completed in late June by many volunteers from the Island, and groups from UWM and the Madison Research Station.

Last year, Midwest BioAg donated soil tests to Gathering Ground. These tests revealed the north side of the vineyard has acidic soil, which is a rarity on the Niagara Escarpment. Grapes do not thrive in acidic soil. Because of this discovery, Gathering Ground has chosen to trial other fruit. Three rows of blueberries and one of lingonberries are now planted in this section of the vineyard to take advantage of these conditions.

Rose Chafers

Last season most of the vineyard crop was wiped out by the rose chafer beetle, a pest that feasts on grapevines and loves sandy soil. The beetle is only active for three to four weeks to eat and mate, spending the rest of the year underground.

The chafer is a growing concern for other gardeners on the Island as they are now found eating through the blooms on peonies and other flowering plants on the south side of the Island. Often, when conventional control of a major pest is removed, populations of that pest can explode and can require several years to balance itself out ecologically. There is not much research on how to fight the rose chafer organically, so Gathering Ground has been implementing several methods this year to try to rid the vineyard of the pest without using harmful pesticides.

These methods include using the organic sprays such as Beetlegone! and Azera, which is a mix

of neem and pyrethrin. They are also combating them manually: shaking the vines in the morning when the beetles are sluggish. They can then fall into ready buckets of soapy water. All of these have proved to be somewhat effective in holding off the rose chafers.

Vineyard manager Russell Rolffs has been scouring research for other solutions. Chafers are most vulnerable in their grub state when in the soil. Mulching, beneficial nematodes, and tilling may disturb the population. There is also some research published in the mid ’90s that suggests farming communities that set up large pheromone traps can wipe out chafer populations over three to four years. As an isolated Island, this may be a great option. Rolffs is looking into costs and more research on this method. If successful, the benefit would be for Island gardeners and the vineyard alike.

Even if the Gathering Ground vineyard does not produce a crop, this year will provide the groundwork for future years tending the vineyard and sharing research that will benefit other organic vineyards in the Midwest. Gathering Ground is always looking for volunteers and donations, for more information email hello@gatheringroundwi.org.

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