Production Information
|
|
Production Information |
|
by Jeanine Davis, Associate Professor and Extension Specialist, Horticultural Science
I've been getting lots of questions on late blight, especially in the western part of the state. So I'm sharing some information I recently distributed to extension agents and listservs in WNC.
There's been a lot of concern about late blight, especially among the organic tomato growers. You should know that there are cases confirmed on tomatoes and potatoes in Buncombe, Henderson, Jackson, Tyrrell, Camden, Pasquotank, and Hoke counties. I'm sure there are many more cases out there, these are just the ones reported through the NCSU Plant Disease and Insect Clinic or confirmed by the pathologist at the Research and Extension Center in Mills River.
Farmers using conventional agricultural chemicals have a pretty good arsenal of products to protect their plants with. Extension agent, Sue Colucci, has information on that and a link to a Late Blight factsheet on her blog at http://wncveggies.blogspot.com/.
Organic growers, this is the big test this year, especially if the tomatoes are out in the open and not protected by a high-tunnel. There is a great article on organic management of late blight on tomato and potato on eXtension. It is written by an extension specialist in Oregon, and I think you will find it very informative http://www.extension.org/article/18361. Copper products (check OMRI list for specific ones), Serenade, and Sporatec are some of the products that may give you some control. The key to using these products successfully is they must be applied BEFORE you have an infection. So if you are going to spray, now is the time to start. Also, you need to get excellent coverage of the foliage. A powered mist blower works great. Also, spray frequently. If you spray and it rains an hour later and washes it all off, spray again. We are on a five day spray schedule with our organic tomato research plots right now. And alternate products. We are using copper every other spray right now. Please remember to read the labels for any product you spray, and pay attention to any REIs (restricted entry intervals) and PHIs (preharvest intervals). For example, following copper sprays, you are not to re-enter the field for 24 hours unless wearing the specified PPEs (personal protective equipment). Also remember not to work your plants when they are wet, clean your tools and picking buckets. Do everything you can not to spread disease from plant to plant. If you already have some infection, remove affected leaves and keep spraying. As always, check with your certifier about any restrictions on product use and timing!
One other note, this is the year to keep close records on the varieties you grow. You will probably notice a big difference in diseases among varieties, especially with heirloom tomatoes. This will help in your variety selections for next year.
Hope this helps!
Dr. Jeanine Davis
Mountain Horticultural Crops Research & Extension Center
455 Research Drive
Mills River, NC 28759
Phone: 828.684.3562 ~ Fax: 828.684.8715
Email: jeanine_davis@ncsu.edu
Maintained by: Bryan A. Konsler
Updated August 5, 2009