Dave Roberts

Dr. Dave Roberts

Dr. Dave Roberts has researched many issues in Michigan’s plant industry, including Oak Wilt, Dutch Elm Disease, and Diplodia Tip Blight of Pines, along with a 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 Green Industry. Dr. Roberts is President, CEO and CBW (Chief Bottle Washer) of The Plant Doctor, LLC…aka the Tree Doctor.

The Plant Doctor, LLC

Diagnosing Herbicide Injury in Landscapes and Nurseries

Start Date/Time:

End Date/Time:

Herbicides provide highly effective and efficient means to eliminate unwanted plants (weeds) in landscapes and nurseries. Unfortunately, with vague labels and misunderstandings about the chemicals in herbicide products, mistakes often happen, leading to impacts on non-target plants. These impacts may cause symptoms ranging from minor cosmetic concerns to severe injury and to plant death. When valuable plants such as trees are involved, liability for mishaps may be staggering; herbicide toxicity issues are often catastrophic compared to other mistakes.

Distinguishing Oak Afflictions

Start Date/Time:

End Date/Time:

Oak trees (Quercus sp.) represent increasingly important components of the Michigan Landscape, whether the landscape is urban or is natural woodlands/forests. The loss of important species of trees (examples: Ash, Elm, and Chestnut), coupled with seemingly almost daily new introductions of pests and diseases (examples: Hemlock Wooly Adelgid, Beech Leaf Disease, Pear Trellis Rust), makes it vitally important that we learn to distinguish the myriad of Oak maladies so that we can properly manage and preserve this important genus of tree.