Late Blight Webinar 2010: 9 - Final Managing Tips

eOrganic authors:

Dr. Margret McGrath, Cornell University

Dr. Sally Miller, Ohio State University

 This clip is from the Late Blight Control in Your Organic Farm Webinar

Audio Text

Continuing on with your management steps. This is a community disease. It occurs, it's really important to notify other farmers and gardeners in your area as well as extension staff so that other people know that the disease is occurring and they can prepare. And now they can get out preventative sprays and try to save their crops. If you realize that you have reached a point where your crop is unmanageable, you're not going to be able to save it, don't just leave the crop there producing spores that will move on to other people's plantings. Really important to treat this as a community disease and get rid of those plants, preferably on a sunny day because the UV rays will kill the spores that you are dispersing by pulling up those plants. You bag them, you can pull up a bunch and cover them with a tarp and the plants underneath that tarp will heat up and get killed, you can dig a hole and burry them, and a lot of growers I know last year used a propane flames to kill them. So there are a lot of ways to get rid of those diseased plants.

This is the community garden here on Long Island where we had an outbreak this spring. And gardeners have learned that this is an important disease. They let me know right away that they thought they had late blight, I diagnosed it and you can see they bagged up those plants and they are leaving that bag out in the sun where the plants and the spores are going to be killed. There was one last plant in here that hadn't gotten pulled yet, here is a close up on the base of that plant. This is less than a week from when those gardeners first saw symptoms. Just another illustration of how severe late blight can be pretty darn early in development. As I said, less than a week from when they saw symptoms and they were out there every day.

So clearly with late blight we need aggressive management to control it. It's not like other diseases, we can't just let it stir out there. We've got to manage aggressively. To minimize the impact for all of us, you can't just think about your own planting, we've all got to be in this together to try and control this. And if we're really aggressive about managing it, there is less chance that to many types are out there and they can come together and then form oospores. It's really important realize that if that happens, those spores can survive in the soil for a couple years and late blight becomes like early blight and septoria leaf spot where they just survive in your farm and are there every year. And that has happened in some parts of Europe, they now see late blight every year. I think that's a really important thing for us to realize that that could happen to us. I think that one of our big challenges and part of why we're all chatting here tonight is so that we're all educated and we understand. I think that we all need to be part of that education, so anybody you know who isn't part of this webinar tonight, make sure they know about late blight and hopefully we can return to it being a very sporadic disease because we certainly don't need it anymore. And just dead plants to illustrate what late blight can do and how managing it is absolutely essential.


Published July 27, 2010

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