Tuesday, June 29, 2010

Cercospora Leaf Spot on Crinum

I'm giving a talk on pests at a Crinum Workshop later this week at Moore Farms. When asked to do it, I think I declared, "Crinums don't really have any pest problems." But in putting this talk together, I've been reminded that they do have a scant few. This is not an overly troublesome bulb.

If you're not familiar with this plant, Crinums are old-fashioned Southern bulbs that are often found around old homesteads. Their bulbs can get really big- bowling ball size- and will form large clumps over time. My grandmother called them Milk-and-Wine Lilies; other names include Cemetery Lilies, Spider Lily, Cape Lily and Poison Lily. Poison Lily. I'd love to know the back story on that name.

One of the common diseases is caused by the fungus Cercospora. The spots are circular with a yellow halo. As the disease progresses, these spots coalesce and cause entire leaf dieback. While it doesn't kill the plant, Cercospora Leaf Spot does impact the beauty and vigor of this bold-textured plant.How do you manage this disease? By keeping the leaves dry.

Fungal plant pathogens need about 8 hours of continuous leaf wetness. If you have an overhead irrigation system that runs late in the day, the leaves will stay wet overnight.....and your chances of leaf spots (and other problems) will increase.

If you have this leaf spot, cut off infected leaves, increase air circulation (to decrease humidity) and keep the irrigation off the leaves.

If you want to know where to get this pass-along plant, check out this month's Southern Living and read about South Carolina native Jenks Farmer and his Lush Life nursery. Their article shows the more beautiful side of this plant.


  1. This looks like Corexoil poisoning happening all over the US. The trees in GA are dying at an alarming rate!

  2. Hi. I've been having this problem with my crinum for the past 3 months. It's the rainy season already here in the philippines and keeping the crinums dry is impossible. How do i treat it? Thanks!



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