Daylily Rust- Where Will It End

Another interesting control example is white pine blister rust. This rust infects the bases of eastern white pine trees, causing cankers that eventually girdle and kill the tree. It used to be endemic in the central Appalachian Mountains and limited the production of the tree. The alternate host of the blister rust are plants in the genus Ribes which include currants and gooseberries. Gooseberries used to be common natives in the central Appalachians. During the great depression, one of the work projects of the Civilian Conservation Corps was to eliminate the gooseberry from the ecosystem. Day after day, crews would scour the mountain forests, marking their progress by stringing endless miles of string, searching for gooseberry bushes growing in the under story. When found the ill fated shrubs were pulled and hung upside down in neighboring vegetation. In Virginia, the project was conducted very thoroughly and effectively eliminated the gooseberries in most localities. The result has been a gradual increase in white pine in the forests of the region.

The daylily rust, though can successfully short circuit this alternate host requirement and directly infect daylily plants directly from daylily plants. Even if one were to isolate daylilies from the alternate host genus, Patrinia, it can carry on right on its original host and spread directly from one Hemerocallis to another. A Theororised daylily rust lifecycle may help you visualize how this works.

So where did this disease come from? Well, to begin with, it apparently is not really a new disease. It was first identified and described in literature from Asia in 1880. For what ever reason it did not reach this country (at least in a highly virulent form) until the summer of 2000. It is suspected that the current disease inoculums arrived on daylilies brokered and shipped in from Costa Rica into Georgia. In the summer of 2000 this disease was reported in the states of Alabama, Florida, Georgia and South Carolina.

Where has it gone? In a SNA research conference presentation, Dr. Jean L. Williams-Woodward and James W. Buck, Univ. of Georgia state: "As of June 2001, daylily rust has been identified in ten U.S. states (Alabama, California, Florida, Georgia, Louisiana, Minnesota, Mississippi, Tennessee, Texas, and South Carolina). The spread of the disease has been primarily through the sale and trading of infected daylilies."

The National Plant Board, in a recent The copyright of the article Daylily Rust- Where Will It End in Plants & Trees is owned by Wesley Ford. Permission to republish Daylily Rust- Where Will It End in print or online must be granted by the author in writing.