Earlier this month, the Land Trust was fortunate to receive funding from Maine Outdoor Heritage Fund to support efforts to combat hemlock woolly adelgid on our conserved lands. Hemlock Woolly Adelgid is an invasive insect native to Asia that was first detected in the United States in the 1920’s and has been making its way to Maine ever since, aided by the transportation of infested hemlock (such as firewood and infected nursery stock). Hemlock Woolly Adelgid feeds exclusively on hemlock trees, capable of leading to tree mortality in a decade or less after they become established and their population increases.
Hemlock trees make up approximately 10% of Maine’s forests and provide important wildlife with both food and shelter, in addition to being commonly found growing along streams and rivers, holding riverbanks in place and cooling stream temperatures. Hemlock Woolly Adelgid was first detected in the Brunswick-Topsham area in 2010 by the Maine Department of Agriculture, Conservation, and Forestry (MDACF) and is now widespread. While there is no silver bullet when it comes to managing Hemlock Woolly Adelgid, particularly on a forest wide scale, and they are here to stay, there are biological controls that have been approved by the FDA that target and feed only on Hemlock Woolly Adelgid. These biological controls are insects that target and feed only on Hemlock Woolly Adelgid, and over the last two decades the State of Maine and numerous land trusts have released these biological control beetles to help combat the rising population of Hemlock Woolly Adelgid.
Thanks to the grant funding provided by Maine Outdoor Heritage Fund, the Land Trust will be purchasing and releasing colonies of the lady beetle (Sasajiscymnus tsugae) on two properties owned by the Land Trust. These two properties have significant hemlock populations that meet the criteria as release sites. We will begin with releasing the beetle on 1-3 trees that provide the best chance for the lady beetle to survive and sustain a breeding population that will increase over time and spread to other trees where Hemlock Woolly Adelgid is present. The Land Trust will be partnering with the MDACF to select the release sites, conduct the release, and work on follow up protocol to monitor the presence of the beetle over time with the goal of limiting Hemlock Woolly Adelgid populations to help prevent hemlock tree mortality. The ladybird beetle is reared by only one lab in the country currently, resulting in a strict timeline of when beetles can be ordered and when they ship. The Land Trust expects to receive them in the spring/early summer of 2024, so stay tuned for news on the upcoming release!