Conifer Conundrum

Jan 29 2019 - 4:15pm

Conifers are important components of our nursery and landscape industries. Unfortunately, conifers have been experiencing many debilitating and decline issues in recent years. It is vitally important that we be able to distinguish among non-lethal vs. lethal problems, diseases vs. pests, and cultural vs. environmental issues.

What’s the difference between white pine decline and white pine root decline? How do we differentiate needlecast diseases from Phomopsis and Cytospora cankers of spruce? Making an accurate diagnosis is necessary before implementing the proper management practices necessary to preserve the health of our conifers in Michigan landscapes and nurseries.

Session Track: 


The Plant Doctor, LLC

Dr. Roberts retired from Michigan State University in 2018 after committing four decades to advancing MSU’s Land Grant Mission, originally signed into law by President Abraham Lincoln during the midst of the American Civil War. He has published hundreds of articles and has taught hundreds of lectures and workshops.

Dr. Roberts has researched many issues in Michigan’s plant industry, including Oak Wilt, Dutch Elm Disease, Diplodia Tip Blight of Pines, along with variety of cultural problems such as plant nutrition and herbicide toxicity. During his career, he has discovered a variety of new diseases and pests such as Phomopsis Canker of Spruce and the first bacterial wilt disease of turfgrasses in North America.

In the early 2000s, his research on Ash Decline in Southeast Michigan led to the discovery of the invasive Emerald Ash Borer in North America.

In his retirement, Dr. Roberts intends to remain active with the Arboriculture/Landscape/Nursery industries. Dr. Roberts is President, CEO and CBW (Chief Bottle Washer) of The Plant Doctor, LLC…aka The Tree Doctor. His contact information remains the same: Phone (248) 320-7124; Email