Wednesday, September 23, 2009

Downy Mildew: Hops

Hops are a new crop to western North Carolina. As with all new crops, it is going to take some time to figure the ins and outs of hops production. We are learning from our current hops growers about when and how to harvest, yield per bine, how to dry the hops cones, what varieties work well for WNC and how to control mites, leafhoppers and other pests.

In addition, as you all know, WNC is very humid and sometimes wet! As a result, we struggle with the control of plant diseases. Hops are no exception. Upon my last visit to the hops yard, I found some leaves exhibiting symptoms that had me concerned. I had discovered what I initially thought was downy mildew, caused by the fungal-like organism, Pseudoperonospora humuli, on some lower hops leaves.

Downy mildew causes angular lesions, bound by leaf veins.
Note: the large circular lesion is not caused by downy mildew

Underside of leaf infected by P. humuli

Underside of leaf infected by P. humuli

Upon inspection using my hand lens, I was able to confirm that there was downy mildew sporangia emerging on the underside of the leaf surface. Because I love learning about plant diseases, I had to take a closer look using a dissecting microscope (about 20-45x magnification).

The fuzzy growth of P. humuli on the underside of the leaf surface.

Sporangia (spores) and sporangiophores of P. humuli on underside of hops leaf.

Sporangia (spores) and sporangiophores of P. humuli on underside of hops leaf. You can really see the football/lemon shaped spores at this magnification.

After the dissecting microscope, I had to take a closer look at the sporangia and sporangiophores using the light microscope. Check out these beautiful pictures of P. humuli up close and personal (200-600x magnification)!

Football/lemon shaped sporangia and dichotomously branched sporangiophores (note the pointy ends upon which the sporangia are borne).

Another picture of the sporangia and sponrangiophores of P. humuli.

P. humuli sporangia. Note the small raised bump at one end of the sporangia. This is the papilla and is characteristic and diagnostic of this pathogen.

Strategies for the Management of Hops Downy Mildew

To manage downy mildew of hops it will take an integrative approach using some or all of the following strategies.
  • Host Resistance. One of the most effective management strategies for hops downy mildew is to plant resistant varieties. There is no variety that is immune to downy mildew, but 'Fuggle', 'Cascade', 'Newport' and 'US Tettnang' are resistant. 'Centennial', 'Willamette', 'Chinook', 'Liberty', 'Cascade', 'Bullion' and 'Brewer's Gold' are tolerant. 'Late Cluster', 'Galena', 'Horizon' and 'Nugget' are susceptible. Interestingly, many of the varieties that are resistant to downy mildew are susceptible to powdery mildew and vice versa. For a complete listing of varieties inlcuding disease susceptibility, pedigree and chemical characteristic, see the Compendium of Hop Diseases and Pests edited by Walter Mahaffee, Sarah Pethybridge and David Gent. This book is a must have for a hops producer!
  • Disease Free Stock. It is always important to purchase disease free plant stock! Ask your supplier.
  • Pruning. P. humuli overwinters in dormant crowns and buds of hops. During the winter and spring, P. humuli may spread into developing buds and cause the new shoots to be systemically infected. Pruning helps to reduce downy mildew levels in already infected plantings. Pruning hops yards as late as possible in the spring can help to reduce the amount of downy mildew in the yard, however if you do it too late you may reduce yield by dealying training.
  • Manage Moisture. Moisture on the leaves favors disease development, so using practices that reduce leaf moisture will also help to manage the disease. Avoid overhead irrigation.
  • Reduce Inoculum. Stripping diseased leaves after training may help reduce disease in the upper plant canopy.
  • Early Harvest. Early harvest may be beneficial in minimizing cone infection. Downy mildew favors the cool, wet weather that occurs late season in WNC.
  • Timely Fungicide Application. Many hops growers rely on fungicide use for downy mildew control. Because P. humuli produces so many spores (progeny), it is impoprtant to employ tactics to prevent fungicide resistance. To read more about fungicides for the management of downy mildew of hops visit Oregon State Extension's Factsheet. Some organic fungicides include copper products and Sonata (Bacillus pumulis strain QST 2808).
If you suspect you have downy mildew in your hops yard. Let me know, I will do my best to help you confirm it and come up with a strategy for control.

I would like to thank Dr. Kelly Ivors and Landis and Dreama for letting me use their awesome microscopes and camera to take these incredible pictures!!

Monday, September 21, 2009


Radial cracking of tomato due to excess rain

We have been experiencing some very rainy weather conditions in WNC for the past few days. Some places are reporting better than 8 inches of rain just in the past 3 days!

The National Weather Service (NWS) issued flood warnings to Henderson, Polk and Transylvania Counties on Sunday night. This afternoon the NWS issued another flood warning until 5:30 pm to Transylvania, western Henderson, Haywood, Buncombe, Swain, Madison and Jackson Counties in WNC.

Some considerations that are important to make during heavy rains are:

1. Equipment. Please make sure that if there is heavy rain or the possibility of flooding that equipment gets moved to a place where it cannot be damaged. I know a few growers who took the time to move their irrigation pumps further up the banks to accommodate the flowing rivers and creeks. Also, don't forget to move port-o-johns! You don't want yours floating down the river!

2. Flooding and flood contaminated produce. With large amounts of rain flooding of fields from river, creek or stream water is a major concern. I am sure that you all remember Hurricanes Frances and Ivan! Because there is no way of knowing what kinds of contaminants are found in flood waters, crops that have been flooded CANNOT be harvested and sold for human consumption. A chlorine rinse is NOT adequate to guarantee safety of the produce. Crops intended for human consumption are considered contaminated if they have been covered with flood waters from rivers, creeks or streams. Growers should distinguish between rainwater that accumulates on a field because of excessive rainfall versus fields covered by flood waters from risen rivers, creeks or streams.

Hopefully you have purchased Noninsured Crop Disaster assistance Program (NAP) insurance. If your crop had been flooded and you have NAP insurance, please contact your local Farm Service Agency for assistance.

Here is a document from the Food Science Dept. at NCSU that talks about flooded crops:

Good luck!

Wednesday, September 16, 2009

Beginning/Transitioning to Organics Course

NC Cooperative Extension is presenting a new and exciting course this fall!

Beginning/Transitioning to Commercial Organic Production, begins on Tuesday 22 Sept (the first day of Autumn!). This is a nine-week course that will be held on Tuesday evenings from 5:30 - 8 pm at the Buncombe County Cooperative Extension office in Asheville.

The topics to be covered include:
  • Intro to organics and organic production in NC (with Dr. Jeanine Davis)
  • Soil fertility and management in organic systems
  • Crop rotation and cover crop design
  • Weed management
  • Insect management
  • Disease management
  • Post-harvest handling and food safety
  • Marketing (with Megan Ray from ASAP)
  • Certification paperwork and Q & A (with Tony Kleese of the Earthwise Company in Wake Forest, NC and Eastern Carolina Organics)
The fee for the entire nine-week course in only $25, which covers the fee for an extensive, informational notebook.

To register or for more information, contact me at

I look forward to seeing you all there!

Monday, September 14, 2009

Ingles Wants to Buy Local, Organic Produce!

Ingles Market and NC Cooperative Extension Service would like to invite you to an informational meeting regarding how and why to sell your produce to Ingles. The meeting will be held on Friday September 18 from 2 – 4 pm at the Haywood County Cooperative Extension Office located on 589 Raccoon Rd. in Waynesville, NC (located across from the Mountain Research Station).

Representatives from Appalachian Harvest, Albert’s Organics and Ingles Market will discuss exciting marketing opportunities for producers interested in the commercial production of organic produce. Though this meeting will focus on marketing and selling commercial organic produce, representatives will also discuss opportunities for selling conventional produce.

Speakers include:

Robin Robbins- Sales & Marketing Manager for Appalachian Harvest

George Borzilleri- Senior National Account Manager for Albert’s Organics

Brent Biddix- Senior Organic Produce Buyer for Ingles Markets

Jim Ray- V.P. Ingles Markets/ Produce Department

This is an exciting opportunity for growers who are interested in expanding their markets and selling produce to Ingles!

If you plan to attend, please call the Haywood County Cooperative Extension Office at 828.456.3575.

Wednesday, September 9, 2009

Organic Production Training

I am in Chapel Hill (hold your groans Wolfpack) for an advanced organic production training for extension agents. This is a unique program that has brought together agents and educators from Alabama, Arkansas, South Carolina and North Carolina with the goal of creating a network of agriculture professionals with expertise in organic production. The training is funded by a Southern SARE grant that was put together by Dr. Elena Garcia (U. Arkansas), Dr. Jeanine Davis (NC State) and specialists at Clemson and Auburn.

On Tuesday, we spent time in the classroom learning about the following topics:
  • A brief overview of organic certification, including National Organic Program Standards, transition time and the Organic Materials Review Institute (OMRI) - Taught by Tony Kleese of the Earthwise Company in Wake Forest, NC
  • How to answer questions about controlling disease and insect problems organically - Taught by Debbie Roos, agriculture agent in Chatham County, NC and creator of the Growing Small Farms website, which many of us use regularly (I know I do!)
  • How to help a grower design a crop, cover crop, and crop rotation plan - Taught by Richard Boylan, area specialized agent in Watauga and Ashe Counties, NC
  • Successful extension programs in organics, with examples from Debbie and Richard
The topics and speakers were outstanding! Debbie and Richard are great examples of successful agents with successful programs. They are inspiring and energizing. It was great to hear about these agents' programs and to get ideas for programs we can do in WNC.

Today we spent all day touring farms in Chatham County and learning from successful, sustainable growers about their techniques and opinions.

The first farm we visited was Timberwood Organics in Efland.

Here we met Ray Christopher, an impressive and experienced farmer who was happy to see us, but definitely had his mind on surfing.

Ray showed us his chard production...

Lettuce transplant production...

Bok choy production...

and squash production, which was remarkably disease free for a fall planting.

Next, we were off to Peregrine Farm in Graham, NC. An intensive vegetable and cut flower operation, which utilizes high tunnels.

Here we met the man, the legend, Alex Hitt and his equally impressive wife, Betsy. These two are rock stars in the world of organic production. They have been growing for more than 25 years and are extremely knowledgeable and excellent teachers. Below Alex is explaining his motto of "Farm Smarter Not Harder" and the interesting structure of Peregrine Farm, which started as a corporation funded by members of the community. Today, Alex and Betsy are the sole shareholders of Peregrine Farm and have diverse marketing avenues including local tailgate markets, Weaver St. Market, and local restaurants.

Here we saw Zinnias and other cut flowers. I learned about the soldier beetle, seen below. Debbie taught me that soldier beetle adults feed on soft-bodied insects like aphids and the soldier bug larvae feeds on grasshopper eggs. Cool!

The Hitts have a passive solar greenhouse where they start better than 250,000 transplants per year!

Alex explained that the insect balance on Peregrine Farm is amazing.
He also stated that other than a few foliar diseases on tomato and Zinnias, one of the biggest disease problems they struggle with is Southern Stem Blight (Sclerotium rolfsii) on tomato and pepper. To control it, sanitation is key. Diseased plants are culled as early and carefully as possible and burned. Irrigation is buried deeply in areas with problems in order to discourage water from the area where mycelium is actively growing. This helps to retard fungal growth and discourage the spread of the fungus.

Alex also described weed management on Peregrine Farms. He stressed that weed management really is crop dependent. Here are some of the techniques they use:
  1. Dense planting, to shade out weeds. Ex. lettuce is grown on 3 rows/bed and cultivated only once
  2. Landscaping mulch,
  3. No-till,
  4. Mowing,
  5. Cultivation and wheel hoeing, and
  6. Flame weeding (beets and flowers that take a long time to germinate)
Here is peppers grown using no-till.

Finally, Alex showed us his coolers. He stressed that no matter how great a job you do prior to harvest, if you do not handle that produce properly post-harvest, all of your hard work was wasted. They have 2 coolers, one for cool season flowers and vegetables (32 degrees F) and one for warmer season crops (45-50 degrees F).

Read more about Peregrine Farm at Southern Sustainable Agriculture Working Group's website.

Next, we moved onto Benjamin Vineyards in Graham, NC.

Here we met Nancy Zeman, who treated us to wine samples...

and her husband Andy who showed us around the vineyard where they practice "sustainable winegrowing".

It was a great treat to taste the different varieties of muscadines, especially coming from WNC where muscadines are harder to find.

Next, we were off to Central Carolina Community College (CCCC) in Pittsboro, where they have a Sustainable Agriculture Program (2 year associates degree, 1 year certificate or continuing education classes). At CCCC we met the Land Lab (student farm) manager, Hillary, a graduate of the program. Hillary explained that they have 1 acre in production that is split into 8 production blocks.

About half f the blocks are in produce and the other half are in cover crops. Below is some buckwheat.

Hillary was particularly proud of the tomatoes that she was cultivating from suckers. Her third generation planted in the high tunnel. She explained that she simply took suckers a few inches in length, stripped any flowers, placed them in a vase with willow cuttings (known to have rooting properties) and in 7-10 days she had plants ready to be transplanted. Very impressive!

We got to see the BCS rototiller and hand tools that are used on the farm. All the beds were made by hand. Tony Kleese explained that the BCS is a great/essential tool for small scale (less than 2 acres) agriculture. It has a PTO shaft and you can easily mount other equipment on it, like a mower.

The CCCC Land Lab was truly an impressive site. The farm is expanding to twice its size in the next year. There are also plans to make the program even more holistic, bringing in a culinary program and new crops, like southern apple varieties and other perennial crops. They even have a pizza oven!

Our final stop for the day was at Eastern Carolina Organics (ECO) where Sandy Kronik and Todd Dunke explained how they market and distribute organically grown produce in the Carolinas. ECO is farmer owned; 80% of the sales go back to the farmers!

At ECO products are pooled from diverse growing regions throughout the Carolinas in order to meet a demand for a steady stream of high-quality, seasonal produce year round.

As you can tell, it was a busy day. But, I certainly learned a great deal - much more than I could fit here!

One of the most impressive things about today was that every farmer we met was not only focused on organic and sustainable production practices and high-quality produce, but also on a high-quality of life. Each grower stressed the importance of taking time to take care of themselves, because, afterall their hard work and energy must also be sustainable.

Special thanks to all the farmers, agents and specialists involved in this training.

If you want to learn more about organic production of vegetables, please consider taking the Transitioning to Organics nine-week course this fall starting on 22 Sept.