Wednesday, July 25, 2012

Chinese Medicinal Herbs Update and Survey

Chinese peony in April

There is so much going on with Chinese medicinal herbs right now, I don't know where to start!  So here are some updates in no particular order:
  • Our little Chinese medicinal demonstration gardens at the Mountain Horticultural Crops Research Station are teaching us so much about what likes to grow here in the southern mountains of western NC and what is "not so happy".  I will post a whole string of photographs soon.
  • Our farmer and herbalist cooperators continue to grow the same herbs as we are growing at the research station.  Last year some of them sold Chrysanthemum, Ju hua, to Golden Needle.  I then received a phone call from one of the practitioners who purchased some of the locally grown Ju hua and he was thrilled with the freshness and high quality of the product.
 Chrysanthemum, Ju hua that we grew last summer
Amy processing Ju hua in 2010.
     
  • I will giving a workshop on growing Chinese Medicinal Herbs at the NC Herb Association's annual summer conference known as Wild Herb Weekend. There we will view a Powerpoint presentation on how to grow the herbs, discuss how to prevent any possible invasiveness problems with plants we are not very familiar with, study vouchers from our gardens prepared by Joe-Ann McCoy at the Bent Creek Germplasm Repository, and study some live plant material. 
  • Jonathan Poston visited our gardens today and did a wonderful blog post on it. Thanks, Jonathan!  About a year ago he taught a class at Galen University that did a survey on demand for Chinese medicinal herbs.

Tuesday, July 10, 2012

Free Webcast on Brown Marmorated Stink Bug Management in Tomato

Photo from USDA

Phil Bogdan of the Plant Management Network sent me this notice that I am passing on to you.  The Brown Marmorated Stink Bug can cause a great deal of damage to your tomatoes and we definitely have them in western North Carolina!

Brown Marmorated Stink Bug Management Addressed in New Tomato Webcast

Few crop pests have received as much attention as the brown marmorated stink bug…and for good reason.  Aside from heavily damaging various crops in the mid-Atlantic U.S., this economically important pest has been also been spreading westward across the U.S.

The latest Focus on Tomato presentation, authored by Dr. Tom Kuhar, Associate Professor of Entomology at Virginia Tech, helps consultants, growers, applied researchers, and other practitioners better understand and manage the brown marmorated stink bug (BMSB), particularly in tomato crops.

The presentation includes…
- A short biological and ecological background of the BMSB

- Illustrations of the BMSB and the damage they cause

- Population data for tomato crops

- Insecticide efficacy data for managing the BMSB

- Best BMSB management practices

This presentation is open access through October 31, 2012 and can be viewed at http://www.plantmanagementnetwork.org/edcenter/seminars/tomato/BMSB/.

Users can view other recent webcasts in the Focus on Potato resource at http://www.plantmanagementnetwork.org/fot.

Focus on Tomato is a publication of the Plant Management Network (PMN), a nonprofit online publisher whose mission is to enhance the health, management, and production of agricultural and horticultural crops. It achieves this mission through applied, science-based resources. PMN is jointly managed by the American Society of Agronomy, American Phytopathological Society, and Crop Science Society of America.

To take advantage of PMN's full line of resources, please sign up for its free online newsletter at:



Thursday, July 5, 2012

Late Blight Confirmed in Western North Carolina


I just received a phone call from our plant pathologist, Dr. Kelly Ivors. Late blight has been confirmed in a commercial tomato field in western North Carolina. Now is the time to start protecting your tomatoes. If you are a conventional grower, you can access the tomato spray guides that Kelly has prepared for recommendations.

If you are an organic grower, the product that is most effective is copper. If you are certified organic, please check with your certifier to make sure that you can use copper and how frequently. Kelly recommends that if possible, your first spray should be copper.  You can then rotate with other products such as Regalia, Serenade, Sporatec, and Oxidate.  eOrganic has an excellent article on Organic Management of Late Blight.  There is also a webinar for Late Blight Management on Organic Farms and one for Late Blight Control in Your Organic Garden.

More information from Dr. Kelly Ivors.  She is sending this out to growers and it will be posted as a Pest News Alert:

Late blight confirmed on tomatoes in WNC


Kelly Ivors, Extension Plant Pathologist

During this 2012 season, late blight on tomatoes isn’t late. It was already confirmed in commercial potato and tomato fields on the NC coast weeks ago, however, we weren’t sure when we would see it in western North Carolina, where a substantial amount of tomatoes are grown commercially in the mountains. Today (July 5th, 2012) we confirmed late blight from foliar samples collected on July 3rd in a conventional field of tomatoes in Mills River, NC (Henderson County).

Without proper preventative measures and the right weather conditions, some diseases like late blight can completely defoliate and destroy a crop within two to three weeks. Due to moderate temperatures, frequent rainfall, and heavy morning dew during the growing season, late blight on tomatoes, caused by Phytophthora infestans, can be severe in the mountains of North Carolina, as well as in late plantings in the piedmont. Despite intensive efforts for over 150 years to control P. infestans, it remains one of the world’s most costly plant pathogens, concerning either direct loss and/or in the need for intensive use of costly fungicides. The recent spread of aggressive, Ridomil-resistant strains of this pathogen on tomatoes in NC has further aggravated the problem, making the pathogen much harder to control. 

The pathogen attacks all aboveground parts of the tomato plant. The first symptoms of late blight on tomato leaves are irregularly shaped, water-soaked lesions (Figure 1); these lesions are typically found on the younger, more succulent leaves in the top portion of the plant canopy. During humid conditions, white cottony growth may be visible on the underside of affected leaves (Figure 2). As the disease progresses, lesions enlarge causing leaves to brown, shrivel and die (Figure 3). Late blight can also attack tomato fruit in all stages of development. Rotted fruit are typically firm with greasy spots that eventually become leathery and chocolate brown in color (Figure 4); these spots can enlarge to the point of encompassing the entire fruit.

Causal Organism
Late blight of tomato is caused by the fungus-like organism Phytophthora infestans. The pathogen is best known for causing the devastating Irish potato famine of the 1840's, which killed over a million people, and caused another million to leave the country. Besides tomatoes, P. infestans can only infect a few other closely related plants including potato, petunia and related solanaceous weeds such as hairy nightshade. The pathogen is favored by cool, wet weather; clouds protect the spores from exposure to UV radiation by the sun, and wet conditions allow the spores to infect when they land on leaves. Nights in the 50's and days in the 80's accompanied by rain, fog or heavy dew are ideal for late blight infection. Under these conditions, lesions may appear on leaves within 3-5 days of infection, followed by white cottony growth soon thereafter (Figure 2). This white cottony growth is a sign of rampant spore (sporangia) production. Although spores may also be produced on tomato fruit, they are more commonly produced on leaves. Sporangia can be spread readily by irrigation, equipment, wind and rain and can be blown into neighboring fields within 5-10 miles or more, thus beginning another cycle of disease.

Disease Management

Host resistance
Plant resistance is not currently an integral component in late blight management for commercial production of fresh market tomatoes. However, new breeding lines resistant to some strains of P. infestans have recently been developed at the Mountain Horticultural Research and Extension Center in Fletcher, NC by tomato breeder Dr. Randy Gardner. A new campari-type (small fruited) variety called ‘Mountain Magic’ that has resistance to some strains of P. infestans, in addition to early blight, which should be available to growers in the following years.

Chemical
There are several diseases that attack tomato leaves and fruit in this region. Therefore it is necessary to use a combination of different products in a spray program to optimize management of these diverse pathogens, including strobilurins, mancozeb, and chlorothalonil. One consideration is that different products have different preharvest intervals (PHI). A product with a PHI greater than 1 day such as mancozeb (PHI = 5 days) cannot be used when harvests are done 2 or more times per week. Another important consideration is fungicide resistance management. For example, pathogens may develop insensitivity (resistance) to the strobilurins (i.e. Amistar, Cabrio, Quadris or Tanos) if these products are used too frequently.

The application of fungicides plays a significant role in the control of late blight of fresh market tomatoes; however mefenoxam resistant strains of the pathogen have been identified throughout the southeast. Fungicides containing mefenoxam are recommended only when weather favors disease development and resistant populations have not been identified in the area that season- usually this means mefenoxam can ONLY be applied for the first application when it is first found in a county. Resistance development to this active ingredient can be very rapid; use of this product after pathogen establishment in the area is not warranted or recommended.

Commercial growers in western NC should apply protectant products since controlling late blight preventatively is better than after infection. Before late blight infection occurs, (Jeanine's comment: these product recommendations are for conventional growers) mancozeb products such as Dithane, Manzate and Penncozeb work well early in the season before harvest (5-day PHI); chlorothalonil products (Bravo, Equus) work best during fruit growth (0-day PHI). In addition, several other chemistries such as cyazofamid (Ranman), fluopicolide tank mixed with a protectant (Presidio + chlorothalonil), and mandipropamid (Revus TOP) work well against this pathogen as foliar sprays.

Table 3-55 of the SE Vegetable Crop Handbook provides efficacy ratings against this disease. If you do not have a hard copy of the handbook, you can access it online
In addition, the NCSU tomato spray program web site can provide advice on spray schedules and rates. The late blight products come into the spray program at week 9.
 
Figure 1.The first symptoms of late blight on tomato leaves are irregularly shaped, water-soaked lesions.


Figure 2. During humid conditions, white cottony growth of P. infestans may be visible on the underside of affected leaves.

Figure 3. P. infestans can cause leaves to turn brown, shrivel and die.

Figure 4. Infected fruit are typically firm with spots that eventually become leathery and chocolate brown in color.
Figure 5.  Lemon-shaped sporangia of P. infestans attached to sporangiophores.

Tuesday, July 3, 2012

Hop Field Day in Raleigh-change in directions & meeting place


I already made these changes on the original post, but I want to make sure that those of you who subscribe to this blog or get the changes on Facebook are aware of this.  This relates only to the Hop Field Day in Raleigh on July 14th:

 Directions. We just got word from the farm crew that they'll be working on the main road to the station on the day of the field day. So, you won't be able to go down Chi Road that day. Please go down Inwood Road (a slightly more roundabout route) and we will meet at the 'J Edward Booth' building (parking adjacent) instead of at the pole barn. This is a larger nicer building anyway.

Here's the farm map with all those roads listed on them:http://www.soil.ncsu.edu/swetc/maps/lake.pdf

There will be signs posted directing people around.