Agave Ringspot Virus
I seldom miss an opportunity to marvel at a ‘picturesque disease’ on plants. As a classic plant pathologist, I occasionally see plant virus symptoms as a form of artwork. This week across my desk, I was presented with an Agave, Dwarf Century plant (Agave desmettiana Variegata) leaf displaying symptoms in the form of reddish brown ring spots. The homeowner was upset understandably, as there is no cure for a viral infected plant. In this case, it turned out to be Agave Ringspot Virus. I have not seen the virus before and this one certainly did not let me down.
The virus usually enters the agave plant through careless propagation techniques. The infected plant is symptomless when it is young. Over time, the round spots appear as light colored halos. As it matures, the light-colored halos look dry and sinks deep into the leaf surface then turn reddish then brown and eventually dark brown. The round or oblong patterns coalesces forming elongated blotches of different shapes.
It is best to destroy the infected plant as it serves as a harborage to other healthy agave. One way to reduce the spread of the virus is to decontaminate your cutting tools before and after use with alcohol (70% Ethanol) dip or by flame to larger bladed tools. For more information on Agave, contact your local UF/IFAS County extension agent and resources below.
Agave and Yucca: Tough Plants for Tough Times (link below).
UF/IFAS Gardening Solutions (website)