Keeping blight at bay

Despite a really wet year, our wheat has resisted fusarium head blight. Don’t ask about our apples, though. Ask about our straw, instead.

By Jeff Moyer, The Rodale Institute® Farm Manager

Jeff Moyer is the farm manager at the 333-acre Rodale Institute research farm, and has been here for over 26 years, refining the farm's cover cropping and crop rotation systems. The farm has over 1,000 organic apple trees, a 3-acre CSA, 270 acres in a rotation of corn, small grains, hay, and edible soy beans for a Japanese market, and 25 acres of experimental research plots that have been used to test and compare the yield, soil health and environmental impact of organic and conventional systems for the last 22 years.

"It's been extremely rewarding to work at The Rodale Institute," says Jeff. "Working on projects and with people who are having a positive impact on family farm practices, economics, and environmental stewardship is very fulfilling. The positive changes I've seen on our own farm over the years—and farms around the world— convinces me that we're on the right road."

How to contact Jeff

Jeff's email:

Phone: 610-683-1420

Mailing address:
611 Siegfriedale Rd.
Kutztown, PA 19530


August 17, 2004: Well, we made it through July here in Eastern PA. It’s typically a dry month for us. One where we watch the sky in the evening hoping for a shower to water the corn and settle the dust. Not this year. We’ve been hard pressed to put together three consecutive days without rain. That means small grains were hard to combine, straw was even harder to get baled … and hay – forget it. But I can’t complain. The corn has never looked better, the soybeans are growing, and we did get our wheat, oats and rye off while maintaining high quality in the grain. In fact the wheat tested out very well in terms of its test weight and low vomitoxin level. This is increasingly important as buyers of human consumable grains are testing for this and other mycotoxins.

Vomitoxin? What the heck is vomitoxin?

Vomitoxin (Deoxynivalenol) is a naturally occurring toxin produced by several species of fusarium fungi as a by-product of metabolism. The toxin causes scab or head blight in small grains like wheat, rye, oats and barley. Scabbed wheat tends to have kernels that are lighter in weight, resulting in lower yields--and even 1 ppm of vomitoxin in infected feed has been shown to cause significant rejection and illness in pigs, which are most sensitive to these toxins. The buyers I spoke with are allowing 2 ppm.

Our own wheat was at 0.6 ppm this year. For some thoughts on why ours was so low, and for ideas on preventing the problem, see research manager Paul Hepperly’s comments in the box below.

Vomitoxin is most prevalent when humid warm conditions occur at flowering (May in Pennsylvania). These conditions allow air borne fungal spores to infect the grain through the flowers. Wheat scab can be devastating for both organic and conventional farmers. It lowers yields but, even worse, decreases grain quality to the point where it can be damaging to the health of farm animals and people alike. Scab, also known as fusarium head blight, first appears as a premature bleaching of wheat heads, often called white heads (late June in Pennsylvania).

This bleaching is conspicuous in still green fields. Often only part of the spike, usually the upper part, is affected by scab. At this stage, if you collect 100 random heads and count the fully scabbed and partially scabbed, you can estimate the loss in yield using this formula:

Percent Yield Loss = 1 X the # fully scabbed heads
0.5 X the # of partially scabbed heads

With scab, what appears to be a good looking wheat crop will result in a lower than expected yield. Scab yield losses can reach up to 40% in extreme cases, while test weights can run 20% lower than normal.

We’ve got some rotten apples, but the straw is golden …

This weather hasn’t helped our apple crop. Wet, humid weather increases both disease and insect pressures. This year we are probably looking at around a 60% crop of grade-A fruit. This is down from our expectations of about 75%.

This year we’re baling more straw than usual. Normally, we return the straw from the oat harvest back to the soil. I prefer not to remove the carbon from the system. This year, however, there appears to be a strong straw market, and we’re going to take advantage of it by baling up the oat straw. Two years ago we also received more compost materials than usual, so I have an abundance of compost. My plans are to remove the straw and replace it with compost. I used to apply all my compost in the rotation just prior to corn planting. Now I apply it to oat stubble prior to planting wheat. (For more on our composting operation, and our really cool homemade, industrial grade compost turner, see the new article by Laura Sayre in this edition of the web site, Making and using compost at The Rodale Institute and the slideshow Building your own.)

Most years this system seems to work great since the fields are firmer and can take the traffic of the manure spreader better and I have less competition for my time from other field operations. We are applying the compost at a rate of about 12-15 tons per acre--just what the soil microbes want, and nothing more.

It’s cover crop time again …

We have plans to plant several new cover crop trials for the 2005 season. Of course, we need to plan them now so that we’re ready for the late summer and fall plantings of cover crop, coming up fast. This is an important time of the year for organic grain farms. Without good cover crops nothing will work out next year. It’s a hard time of the year to plan – still lots of field work to look ahead to for this season. But discipline tells us that without this process, failure is a sure thing. So, it’s time to calculate acreage, purchase seed, and prepare the soil for all those cover crops.

This year we’re experimenting with more fall brassicas like radish, mustard and rape. We’ll still plant hairy vetch and vetch in combinations with grains like rye and oats. But, I’m really looking at cover crop combinations that will help my weed management in the organic no-till systems I’ve discussed in other articles.

The other good point to August is “it's vacation time.” I always like to spend the first week of August away from the farm and with my family. This year is no different. The first week of August I’m out of here as they say. So, until I’m back I hope you’re all experiencing the great year we here at The Rodale Institute Farm are having. Enjoy a safe and relaxing August.

From one farm to another,


Victory over vomitoxin
Why are our infection rates low compared to other farmers in the region this year?

This year at The Rodale Institute® farm our vomitoxin test results were very low. In fact, they were the lowest of any wheat the lab had tested this year, in samples from throughout Ohio and Pennsylvania. Whereas 2 ppm is the cut-off buyers will accept, ours was 0.6 ppm. Why did we have a low reading in a year in which others are having significant problems? Since wheat varieties in use are all considered uniformly susceptible, we believe the answer could lie elsewhere. After 30 years of organic farming, we believe our healthy soils help us combat these types of diseases.

Our long-term management practices—including diverse rotations, the use of composts, cover cropping, and conservation tillage—may have something to do with this low expression of pathogenic toxins. In The Rodale Institute Farming Systems Trial® we have increased soil carbon by about 30 percent in 24 years, making a range of nutrients and water more available. Only further research and investigation will tell the final answer. But many farmers who have transitioned to organic farming comment on the reduction of pest and disease problems as their soils improve.

What should you do about vomitoxin? Grain can be analyzed for toxin levels and farmers can avoid suffering animal losses from feeding high-toxin grain. Furthermore, early harvesting of grain can reduce the effects of diseases like scab, which increase with delayed harvest.

While we were unable to find any practical, web-based resources on vomitoxin written specifically for organic farmers, the University of Minnesota Small Grains Field Guide did offer the following advice:

“Reduce scab with crop rotation, allowing at least a one year break between crops of corn or Fusarium-damaged small grains. The severest scab often occurs in wheat that has been planted on the residue of last year’s corn. Tillage to bury crop residues also helps to reduce scab potential. Severely scabbed grain should not be used for planting seed.”

Another interesting note: Researchers working with the Canadian government found that fusarium head blight is more prevalent in some commercial wheat crops where Roundup is used.

All farmers should get to know more about this problem, be aware of its presence and severity, and--in scab-favorable years--test their small grains to avoid experiencing unnecessary losses or risks.

--Paul Hepperly
Research Manager
The Rodale Institute