Monday, July 27, 2009

My Shiny, New Tomato Grader

There are many wonderful aspects of my job as an agriculture extension agent, two of them are working with a diversity of folks and getting my hands dirty.

Last week I got to help out harvesting a variety trial for Harris Moran. The trial involves 27 different commercial varieties of tomatoes (11 Roma and 16 round, red). This was just the first picking of the trial and because we haven't had an abundance of sunny, hot days this summer it was late and only the early fruiting varieties had lots of fruit to be harvested.

After the round, red tomato fruit are picked they are graded based on size and shape. For shape they are given a 1-10 rating, with 1 being flat, 5 being perfectly round and 10 being very tall and elongated. Grading the tomatoes is something I find to be really fun! In a packing operation the packing line does the size grading for you, using holes and conveyors, but in field trials we get to do this by hand.

As a surprise I received my very own, brand new, shiny set of aluminum tomato grading cards (see pictures below).

The tomato grading cards separate fruit by diameter. If a tomato doesn't fit through the top hole but fits through the bottom hole, it belongs in that grade. For example, see the card below. A tomato that is considered a 5X6 will be too big to fit through the top hole of this card but will fit through the bottom hole just perfectly. Pretty easy!

These are a very valuable tool for evaluating the quality and consistency of tomato fruit for a specific variety. And now I have my very own set!

I know, I know... The little things...

Friday, July 24, 2009

Downy Mildew Confirmed in Henderson County!

Downy mildew has been confirmed at 2 locations in Henderson County, NC.

  • July 20 - The first incidence of cucurbit downy mildew in WNC was reported from the Mountain Horticultural Crops Research Station in Mills River. The hosts were butternut squash and cucumber. Disease incidence and severity is very low at that site.

  • July 24 - Cucurbit downy mildew was confirmed this morning in Zirconia (just south of Hendersonville, NC). This was a larger planting, about 8 acres. Spaghetti squash is the most severely diseased, about 65% of plants are showing early (top picture) - more advanced (second picture) symptoms. Sporulation (noticeable on the underside of the leaf) was very heavy on the spaghetti squash (third picture). Cucumber (cv. Jackson) is also affected, though less severely overall (bottom picture). The summer squash (cv. Destiny III) is showing only very early and mild symptoms.

Moral of the story, cucurbit downy mildew is in WNC and growers need to start treating now!

Review a previous post for control recommendations.

Visit the Cucurbit Downy Mildew Forecasting site for more updates.

If you feel you have downy mildew on your cucurbits, bring a sample to your local county cooperative extension office for positive identification. It is important that the outbreaks get reported to the forecasting site.

Monday, July 20, 2009

Cucurbit Downy Mildew- Moderate Risk for WNC

Downy mildew (Pseudoperonospora cubensis) has been threatening cucurbits in NC since early June. There have been no reports of downy mildew on cucurbits in WNC and we have been lucky to have been considered at LOW RISK for chance of infection, until now...

The Cucurbit Downy Mildew Forecasts for today and tomorrow show WNC as having a MODERATE RISK for infection. A MODERATE RISK means that there is a 40-60% chance for cucurbits growing in areas along the course of the trajectory (or trajectories, in the case of multiple sources) to be infected by the pathogen and develop downy mildew. To read about how this is calculated refer to the Downy Mildew Forecasting site.

The trajectories that may effect WNC can be seen below.

As you can see there is the potential of spore deposition in WNC from multiple sources. If the weather continues to include cloudy skies and the potential of rain (to wash the spores from the sky) growers should begin to take action to protect their cucurbit crops.

The following products* have proven very effective for the conventional control of downy mildew of cucurbits:

Presidio 4F (fluopicolide)
Ranman 400 CS (cyazofamid)- must use with non-ionic surfactant
Gavel 75DF (zoxamide + mancozeb)
Curzate 60DF (cymoxanil)

Chlorothalonil and mancozeb products can be sprayed as protectants, but when downy mildew is detected in a field growers need to take a more aggressive approach. *The label on some of these products require that they be tank mixed with a fungicide of a different mode of action. Chlorothalonil and mancozeb products make excellent mixing partners.

A sample spray program might look like this:

Curzate 60DF (3.2 oz/acre) + Manzate Pro-Stick 75DG (3 lb/acre) alternated with Previcur Flex 6F (1.2 pt/acre) + Manzate Pro-Stick 75DG (3 lb/acre)


Presidio 4F (3 fl oz/acre) + Bravo Weather Stik 6SC (2 pt/acre) alternated with Gavel 75DF (1.5 lb/acre)

These treatments can be rotated on a 7-day schedule when downy mildew pressure is great.

ORGANIC GROWERS have a chance to combat downy mildew if they begin applications now before the onset of symptoms. If you wait until infection has established in your planting, spraying will not be effective. The same is true in conventional systems. Some OMRI-listed products that are labeled for the management of downy mildew in cucurbits include: copper, neem, biofungicides (ex. Serenade), peroxides (ex. OxiDate), and bicarbonates (ex. Kaligreen).

I have had a lot of experience with this disease, as my master's thesis was focused on the control of downy mildew on cucurbits. Our research showed that most organic fungicides were NOT effective at controlling downy mildew on cucumber. Once the disease develops and conditions are favorable, it is nearly impossible to control it.

Your best option as an organic grower is to use a copper product. Spray early in the morning to avoid phytotoxicity that may develop in the heat of the afternoon. Spraying copper prior to disease development or at very early onset (very few, mild symptoms), may help suppress the disease, but will not offer 100% control under favorable conditions (cool, wet and humid weather).

If you suspect that you have downy mildew on your cucurbits, please contact your local cooperative extension office. It is very important that these cases are documented and reported to the forecasting site in a timely manner.

To read more about this disease or to view some pictures, visit the blog post from 5 June and the NCSU Factsheet.

In addition, look for updates in the latest NCSU Pest News.

***As always, follow the product label for instructions!***

Monday, July 13, 2009

Food Safety?

It is no question that everyone wants the food they consume to be safe. But, have we crossed the line? Is this really the future of food? I hope not.

Debbie Roos, NC Cooperative Extension Agriculture Agent in Chatham County, has passed on another stimulating and disturbing article from the San Francisco Chronicle about how food safety is going overboard. Crops, Ponds Destroyed in Quest for Food Safety talks about the extreme measures an organic grower is taking to make sure his produce isn't contaminated by wildlife. The article also mentions that these same extreme measures of removing vegetation could be making the produce less safe. All in all, are we rushing forward before we have the science to back it up? What we do have, however, is the experience that tells us local produce is not causing the problem. I'd like to hear your comments!

If you would like to stay abreast of the food safety legislature in Washington, visit President Obama's Food Safety Working Group's website and please send them your comments.

Local Dirt

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Local Dirt is an online site for finding, selling, and buying local food (and local food buyers). We are funded by the National Science Foundation. Local Dirt is the only site that does not charge a markup for selling online.

We come from farm backgrounds and have a goal to give small and mid-sized farmers the same advantages as large distributors. Finding buyers and automating the sales, invoices, and inventory is made as easy and fast as possible.

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Last year we tested the site in Madison, Wisconsin. On June 15th we opened it up nationally. Please help us pass the word on.

Bill Walker
ph: 919-740-8075

Monday, July 6, 2009

Tomato Late Blight

Let me first start off by saying Late Blight of Tomato HAS NOT BEEN FOUND IN WNC, yet. But, it has been confirmed very close by in Northern Georgia.

Late blight of tomato is caused by Phytophthora infestans, the same pathogen that wiped out the potatoes in the Irish Potato Famine of the 1840s. P. infestans is an oomycete organism, a group that is also known as the water molds. The pathogen enjoys cool, wet weather conditions. P. infestans spreads and kills a plant very quickly, especially in ideal conditions. Spores of the pathogen are easily disseminated from infected areas to other areas via wind currents, these spores are protected by cloudy conditions.

Symptoms of late blight appear as large, olive green to brown spots on leaves. You may see a fuzzy, white fungal growth on the underside of the leaves. Symptoms also appear as brown or black lesions on the stems and fruit.

To see some excellent pictures of late blight, visit Cornell's Long Island Horticulture and Extension Center's site and the NCSU Factsheet on Tomato Late Blight.

Late Blight is often confused with Early Blight. Unfortunately, these diseases have similar names, but the symptomology and causal organisms couldn't be more different. If you see bulls-eye lesions on leaves starting on the bottom leaves, you are most likely dealing with Early Blight, a fungal disease, caused by Alternaria solani. Revisit my post Early Blight of Tomatoes for pictures and additional information. Compare symptoms of Early Blight with the pictures of Late Blight from Cornell's link above. Cheryl Smith at UNH has also put together an excellent resource comparing the 2 diseases.

If you think you have Late Blight of Tomato, please contact your local extension office to have it positively diagnosed.

Late blight has been all over the news because of its early arrival in the Northeastern US, which has been experiencing cool and wet weather as of late. The disease doesn't usually occur in that region until late-July or August. This year it is believed that the pathogen hitch-hiked on transplants to retail stores and then to home gardens. It is believed that the disease appeared as early as mid-June.

To read more about the problem in the Northeast visit the following sites/article:

UMass Extension "Late Blight Alert for Potatoes and Tomatoes"

American Vegetable Grower "Late Blight on Potatoes, Tomatoes Confirmed in Northeast" - contains information on management as well

Providence Journal "Irish Potato Famine Fungus Strain Hits R.I. Crops"