In the early 2000s, vineyard growers noticed significant grapevine decline, initially thought to be from cold winter temperatures. Grapevines were growing and producing less, and parts of the vine would die. In 2010, researchers from Agriculture and Agri-Food Canada (AAFC) set out to identify the cause and potential solutions.

After a 3-year research project, AAFC researchers determined the primary cause of the decline was grapevine trunk diseases – a group of diseases each caused by a different fungal species. The fungi infect grapevines through pruning wounds. Their spores land on the wounds and, in favourable environmental conditions, begin to grow. The fungi grow in plant tissues that transport water and nutrients (xylem and phloem), resulting in the development of cankers and/or wood rot. The cankers interrupt the flow of water and nutrients, resulting in the death of spurs, cordons, and/or trunk, and eventually leading to the death of the vine.