Late Blight Identified in Western NC

Late blight has been positively identified in Henderson County.  Please review the NC Alternative Crops and Organics for a synopsis from Dr. Jeanine Davis and control recommendations and descriptions of the disease from Dr. Kelly Ivors - Late Blight Confirmed in Western NC.

Growers are urged to start scouting fields and taking proper preventive measures- it is very hard to play catch up with late blight, prevention is key.

To review previous posts on late blight, click here.

Pennsylvania Potato and Tomato Growers Hit By Late Blight

Penn State Live is reporting the current outbreak of late blight on potato and tomato.  Late blight has not been found in Western NC, but growers should be scouting their fields.

For more information or to see pictures of the disease, review the post from June 3

Read the article: http://live.psu.edu/story/60029

Pest News June 1, 2012

Though this week's NC Pest News does not contain anything specifically about vegetable or fruit pests (though kudzu bugs may be a problem for folks growing edamame), I did want to draw your attention to some possible issues to be on the lookout for.

Cucurbit downy mildew and late blight of potato and tomato are very devastating and rapid moving diseases.  Though we do not have any reports of these diseases in WNC or our immediate surrounding areas, they have been reported in other parts of NC.  Weather has been ideal for both of these diseases in our area, cool and wet.  Also, because weather has been unsettled (many storms moving throughout the east coast) there is a chance that the spores of these pathogens could travel to WNC.

In fact, the Cucurbit Downy Mildew Forecasting site issued WNC a low risk warning on Friday.  Cucurbit downy mildew has both been detected in eastern and central NC.  On June 1, new reports of the disease were confirmed as close as Franklin, Nash and Wake Counties in NC.  Cucurbit downy mildew is also tracking up the east coast into New Jersey.  To view a map of current Cucurbit Downy Mildew outbreaks visit the CDM IPM Pipe website.  Growers are advised to scout for this disease and to report to their local cooperative extension office if they need assistance or to report an outbreak. 

 

Symptoms of cucurbit downy mildew on cucumber are angular lesions that start a pale green and progress to bright yellow and then finally brown (above).  The best way to identify cucurbit downy mildew is to turn the leaf over to look for the downy growth of the pathogen's spores (below). 

 

Late blight on potatoes has also been detected in Camden County, NC and various other states on the east coast.  To view a current map of these outbreaks, visit the USABlight website.  Growers are urged to scout for this disease as well, as we know this can be a deal breaker for organic producers especially.

 

Late blight on a tomato leaf.

  Again, these diseases have not been reported in WNC.  If you suspect you have these diseases in your planting, please contact your local Cooperative Extension office for assistance.  It is reporting and early detection that can save a planting!

Researchers Taking Bite Out of Late Blight

Late Blight on Tomato Leaf

• The North Carolina State effort will focus on the development of an online national late blight reporting and alert system.

• The system, which will show farmers late blight outbreaks across the nation, will include what is known as decision support information on how best to deal with the disease.

North Carolina State University scientists will be heavily involved in a national effort to help farmers better manage a plant disease called late blight, which can decimate tomatoes and potatoes.

Jean Ristaino, a professor of plant pathology in the College of Agriculture and Life Sciences at North Carolina State, and Ryan Boyles, state climatologist and director of the State Climate Office of North Carolina, which is located on North Carolina State’s Centennial Campus, are part of a $9 million, 5-year U.S. Department of Agriculture effort to give farmers better tools to use in dealing with late blight. The effort is being led by the University of California at Riverside but will involve scientists across the nation.

Ristaino said the North Carolina State effort will focus on the development of an online national late blight reporting and alert system. This system, which will show farmers late blight outbreaks across the nation, will include what is known as decision support information on how best to deal with the disease.

Late blight, which is caused by a pathogen called Phytophthora infestans, infects American tomato and potato crops every year, Ristaino explained, but various factors, including weather, determine whether the disease causes significant crop losses from year to year.

The disease was particularly bad in 2009, she added, when cooler than normal temperatures and abundant rainfall helped spread late blight. In 2009, late blight destroyed much of the tomato production in the northeast U.S.

Ristaino said growers can protect their crops from the disease if they apply fungicide prior to a disease outbreak and if they apply the correct fungicide.

The system that Boyles and Ristaino are developing is designed to give farmers the information they need to protect their crops from the disease.

The state climate office will develop an online map that will use information from monitoring teams around the nation to locate late blight outbreaks.

Usually begins in Florida Ristaino said that on the East Coast, the disease typically begins each spring on tomatoes in Florida and then spreads to other areas by weather events.
The spores that cause the disease can be carried on the wind, although Ristaino said that in 2009 most pathogen movement was the result of the shipment of infected plants from one part of the country to another.

The severity of the disease also depends to a large degree on the strain, or type, of late blight. Working with scientists at Cornell University in New York, Ristaino will determine the type of late blight found in farmer’s fields. Ristaino said 24 different late blight strains, or genotypes, have been found in the United States, and some of these strains tend to damage one crop, either
tomatoes or potatoes, more than the other.

At the same time, different strains are more or less susceptible to different fungicides. In 2009, five different strains were found on tomatoes and potatoes, but one particular strain, US-22, did most of the damage, she added.

When reporting teams across the country find the disease, they will send samples to Cornell and North Carolina State and to Oregon State on the West Coast. At North Carolina State, Ristaino’s lab will determine the disease genotype. This information along with the location of the disease will be available through the online map.

The late blight website will also include information on how best to protect crops from the disease. Ristaino added that as she and other scientists identify late blight strains they should be able to track the development of strains that are resistant to various fungicides, information that should be extremely helpful in aiding farmers in managing the disease.

Ristaino said the project also includes an educational component. Summer internships will be available to undergraduate students who wish to work on the project.

The reporting and alert system is expected to be operational for the 2011 growing season, and Ristaino said she expects to begin receiving disease samples in early May.

She added that the disease typically moves up the East Coast as the growing season progresses. Late blight is usually found on North Carolina potatoes in June, while it’s usually found on tomatoes in western North Carolina in late July and August.

This year, farmers should be better prepared than in the past when late blight makes its annual appearance.

Source URL: http://southeastfarmpress.com/vegetables/researchers-taking-
bite-out-late-blight

2011-04-08
Byline: By Dave Caldwell, North Carolina State University

Late Blight Confirmed on Tomatoes In Henderson County

Late blight has been positively identified in Henderson County on tomatoes. With the afternoon showers and reports from other parts of the eastern U.S. it was only a matter of time.
Growers are encouraged to scout their fields and begin with control measures.

Sorry I don't have a lot of time to put details in this afternoon, but review my post from last year for some basic information.

Recommendations for conventional producers are chlorothalonil as a preventative if late blight is not found in your field or nearby. If late blight has been identified in your field applications of cyazofamid (Ranman at 2.1-2.75 fl oz/acre), fluopicolide (Presidio at 3-4 fl oz/acre) or mandipropamid + difenoconazole (Revus Top at 5.5-7 fl oz/acre) are recommended. Always read and follow the label when using pesticides! The label is the law.

For organic recommendations, see this article from Alex Stone on eXtension.

More to be reported later. Sorry again for the short note.

UPDATE 1 PM:
This just in from NCSU Plant Pathologist Dr. Kelly Ivors:

"Hey Everybody-

This morning we found and confirmed late blight (by microscopic examination) in one small shaded area of a conventional tomato field in Henderson County. We have not been able to confirm its presence anywhere else in the tomato production areas of NC this summer, so I believe this is the start of the tomato late blight epidemic in WNC. We've had some rains recently and I'm sure it's out there elsewhere now, or soon to arrive.

Fungicide recommendations for controlling late blight on fresh market tomatoes start at week 9 in the NC tomato foliar fungicide guide.

It can be found at this link.

http://www.ces.ncsu.edu/fletcher/programs/plantpath/tomato-spray-guide/tomato-spray-guide.pdf

In addition, there is information (fact sheet) on this disease in North Carolina, including pictures of the symptoms at this link.

Check out the different diseases and select the one under Tomato Late Blight.

http://www.cals.ncsu.edu/plantpath/extension/fact_sheets/index.htm

Please make sure to get your preventative sprays on as soon as possible if you grow tomatoes in late blight prone areas. Chlorothalonil works well as a protectant if you do not yet have the pathogen in your field. If already established in your tomato field, it would be best to apply something more than a protectant like Presidio (+ chlorothalonil) or Ranman.

If you need a confirmation of late blight in your fields, please do not hesitate to call your agent or my lab to submit a sample.

Thanks

Kelly"

Webinar 7/1: Late Blight Management on Organic Farms

There is still time to register for tomorrow's 2010 eOrganic Late Blight Webinar!

Are you an organic producer who battled with late blight last year? Late blight hasn't been found in NC, yet, but if you want some tips and to learn management options for late blight control, this webinar is just for you.

What: Late Blight Management on Organic Farms 2010

When: July 1, 2010 at 8 PM Eastern Time (7 PM Central, 6 PM Mountain, 5 PM Pacific)

Space is limited.

Click here to register
http://www.extension.org/article/28346

Late blight reached epidemic proportions on U.S. farms in 2009. Join eOrganic presenters Dr. Sally Miller of Ohio State University and Dr. Meg McGrath of Cornell University for a free Webinar to hear an update on late blight in 2010. Learn about the late blight disease cycle, how to scout and diagnose the disease, and how to manage late blight on organic farms.

Thank you and hope you can make it!