Late Blight Webinar 2010: 8 - Using Fungicides for Control

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

Really important if you're going to be on it you need to be on a preventative spray schedule if want to be prepared. And that is part of what happened last year to some growers; they weren't used to needing to apply fungicides and they weren't ready and then late blight came in and here's a disease you can't live with and you got to spray but some people weren't ready for doing that. So really good to do in advance. Decide what you're going to use, select it. Make sure it is registered in your state, that was an issue last year in one state when they discovered that there were no organically approved copper fungicides registered for use in that state. Make sure the product you want to use is accepted by your certifier. And then find out when you're going to buy it and determine how much time it's going to take. If it's going to take several days to have that product delivered to you and you wait until late blight starts on your farm, you're going to be behind schedule. Sprayer, got to make sure it's working well. If you've got worn nozzles replace them so you've got good coverage. And make sure that sprayer is calibrated and ready to go if you're going to be using fungicides.

There are several products that are available. In trials that have been done so far, and there have't been too many trails so far looking at organic fungicides, mostly coppers have done well. There is a new product, Regalia, that induces resistance, and there are a couple other products that are available. Unfortunately as I said, there have not been too many studies done yet evaluating these products. It will be really to start getting some feedback from some of you growers who have used products. We are planning set up a blog that we can start interacting and discussing this because I think we all need to work together to figure out the best way to manage late blight.

Here are some results of a study that was done at Oregon State University with a number of different products plus you got a water control. And basically what Alex found with this study is that three copper products gave really good control of late blight, where as the other things she looked at there was no difference in the amount of disease from the water control. So late blight unfortunately is a very difficult disease to control.


Published July 27, 2010

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.