Henderson County 4-H Small Fruit Sale 2012

Henderson County 4-H is selling strawberry, blueberry, blackberry, raspberry and asparagus plants to raise money for awards and programs for youth.

Orders and payment are due by March 15. Plant distribution and sale of extra plants will be Saturday, April 14, at Henderson's Packing House, at 705 Tracy Grove Road.


Here is the link to the order form: http://henderson.ces.ncsu.edu/files/library/45/2012plantorderform.doc

Asparagus Disease

Recently, an organic asparagus grower brought in some diseased ferns. The grower was going to mow off the ferns and burn them, but wanted to identify the problem first to make sure that was the correct thing to do and to minimize problems next year.

It wasn't hard to find the reddish, circular lesions on the stems and discolored needles.

Lesion on asparagus stem.

Discoloration of asparagus fern.

Some of the lesion were older and inside of them, dark black fungal structures were present.


My initial thought was that it had to be either Cercospora blight(Cercospora asparagi) or Purple Spot (Stemphylium vesicarium). The NCSU factsheet on Commercial Asparagus Production mentioned Cercospora blight as a problem in NC, but did not mention Purple Spot.

After looking under the scope, I didn't find any spores that looked like the ones produced by Stemphylium vesicarium, but I did see some other, very elongated spores that almost looked like leaf hairs. Sorry I didn't take a picture, but here is a link to another Cercospora species' spores.

After doing a little more research I found an APSnet Feature Article on Economically Important Asparagus Diseases in the United States. This article stated that Cercospora blight and Purple Spot are easily confused, so I decided to send it into the NCSU Plant Disease and Insect Clinic.

During the next few days, the lesions got larger and coalesced.

Luckily for me, Dr. Averre, whose pictures were included in the above article, was available to do the diagnosis! He identified that the problem was, in fact, Cercospora blight.

There are no known sources of resistance to Cercospora blight, though Jersey Gem does have tolerance to Cercospora. As a result, management must include an integrated approach of sanitation and fungicide applications. Fall removal or burial of the year's fern residue can delay the onset of disease development. This was just what the grower was going to do! Heavily infected ferns should be removed.

Cultural management techniques that reduces leaf wetness are very important for the management of Cercospora blight. These techniques include:

• Using drip or furrow irrigation to decrease leaf moisture. If overhead irrigation must be used, it should be scheduled so that the foliage has time to dry before nightfall.
• Increasing row spacing. This will improve air circulation within the planting.
• Plant asaparagus in areas with good air movement to encourage leaf drying.

To learn more about asparagus production in NC, review the horticulture leaflet Commercial Asparagus Production.

Also, Oklahoma State University has a nice factsheet on Cercospora blight of asparagus.

Asparagus Update

I received a message today from someone who has seen similar symptoms on asparagus to those in my last post. The caller believes that the wilting symptoms could possibly be due to frost. What an excellent observation! It is so easy to forget about frost damage when you visit a farm when it is 80 degrees and sunny out. But, we have had some cold evenings and mornings in the last week or so.

Description of Frost Damage in Asparagus
Spears appear slightly darker green, water-soaked and break off easily. Soft-rotting bacteria can enter the damaged tissue. New spears take several more days to emerge. Temperatures below 33 degrees Fahrenheit may damage the spears.

Though the symptoms I presented in my last post don't exemplify frost damage exactly, I think that having such cold temperatures and wet weather combined didn't help out this particular planting.

Thank you so much for calls and comments. Please leave comments on the blog if you have something useful to add!

Asparagus Does Not Like Waterlogged Soils

Asparagus is a very interesting and exciting perennial vegetable crop. I have to admit, everything I learn about asparagus is new to me, but luckily we have some great asparagus growers here in WNC. Danny McConnell, a grower in Henderson County, was featured prominently in a recent article, Dana Farmer Spears New Market, in the Times-News.

On a recent visit to another area farm, we noticed that the asparagus crowns were wilting (see pictures below). The wilting spears were also hollowed out. The first thing that we noticed was the lack of internal drainage of the soil where the crowns were planted. The soil was very moist and from the reading I had done, I remembered that asparagus prefers well-drained soils.


Because of the wilting, I was tipped off that there was something going on underground. Upon digging into the soil, we noticed it was still very wet from the recent rains. There were also pillbugs or sowbugs present signaling very moist conditions. Luckily, at this point, the roots did not appear brown or unhealthy.

In order to learn more about this problem, I contacted another extension agent in Granville and Person Counties, Carl Cantaluppi (yes, indeed another Italian-American ag agent in NC- its an underground organization. I've already said too much). Carl has a lot of experience with asparagus and even authored and excellent factsheet from Ohio State Univeristy, Growing Asparagus in the Home Garden. After I explained the situation, Carl knew the cause.

The spears were in fact wilting because of the waterlogged soils. Excess nitrogen will only exacerbate the problem. Waterlogged soils will also lead to Fusarium root rot.

So what could this grower do?

• Let the soil dry out, the plants will recover slightly
• Do not replant the established crowns because they will become quite stressed resulting in crown death
• For the recently planted (within the last month) crowns, transplant into raised beds or amend the soil with sand to improve the soil's internal drainage

Ultimately, because asparagus is a long-lived perennial, starting out with the correct soil conditions is key. Get your soil tested to determine phosphorous and potassium needs and to determine the pH. Asparagus requires a soil pH or 6.5-7.5.