Fusarium Head Blight (Head Scab) in Saved Seed

August 15, 2011 in Uncategorized

I was recently asked about planting wheat and barley seed saved from Head Scab (Fusarium graminearum) infected fields.  Growers should keep in mind that just because the grain may have been infected this season does not mean the grain will be infected next year.  Rather, the infection of head scab is a result of the pathogen being present on infected residue and favorable weather conditions.  Growers should take precautions before planting infected seed this fall.  The seed should be cleaned with the intent to remove as many of the small, light infected “mummies.”  I would also recommend a germination test after the cleaning to help determine seeding rate and optimal seeding populations.  A seed treatment should also be applied to help prevent seedling diseases. Bob Mulrooney, Extension Plant Pathologist, wrote an article in the June 10th edition of the Weekly Crop Update on the subject. 

Head scab has been observed in barley and wheat this season in varying amounts. Barley is just now arriving at the grain elevators. The amount of scab that occurs is dependent on the flowering time, the presence of the scab spores that infect the heads during flowering and the weather conditions during flowering. Most of the barley and wheat varieties that we grow have little or no resistance to head scab. The fungus can be present on old corn stover, and residues of old barley and wheat crops. What drives this disease is wet, warm weather during the flowering period. If the heads of barley or wheat are infected with the fungus (Fusarium graminearum) that cause head scab, that fungus can produce several toxins that can contaminate the grain. These toxins are often referred to as vomitoxins because they can cause feed refusal in non-ruminant animals. The most common vomitoxin that is produced by the head scab fungus is deoxynivalenol or DON for short. DON production by the fungus is extremely variable depending on environmental conditions. The presence of scab on the grain does not mean that the grain has to have DON nor does high or low levels of scab relate to the amount of DON present. A high level of scabby kernels in the harvested grain means that DON will likely be present.
What about the saving or using seed from scab infected fields? As much scabby wheat kernels as possible should be removed from good seed during combining and seed cleaning. This is not easily done with barley or may not be possible because barley does not get as light as wheat. Saved seed kernels can be infected with Fusarium, and seed treatments can reduce the effects of Fusarium on seed. Fusarium on seed can cause a seedling blight of barley and wheat but the seedling infections do not result in head scab or DON in fields that might be planted with infected seed. In fact some studies have shown a reduction of scab infections in seed during storage. Low levels of scab infected wheat or barley can be saved for seed if properly handled and treated without any risk of scab occurring in the crop from that seed.
Another issue for barley producers is that the threshold levels of DON in wheat may not be the same compared to barley presuming that the barley is not intended for human consumption. The DON threshold for wheat is 1 ppm because of human consumption concerns. Barley for feed can have up to 10 ppm without harmful effects depending on the animals being fed and the proportion of infected grain being fed. In my opinion barley should not be held to the same threshold as wheat depending on its destination or final use. See the following information on DON levels in food and feed.
What are the critical levels of DON for use in food and feed?
The concentrations of DON in grain are expressed as parts per million (ppm). One ppm is equivalent to 1 pound in 1 million pounds, 1 penny in $10,000, 1 minute in two years, or 1 wheat kernel in 80 pounds of wheat. The U.S. Food and Drug Administration (FDA) has established DON advisory levels to provide safe food and feed. Unlike aflatoxin in corn, DON is not a known carcinogen. Furthermore, grain with DON would have to be ingested in very high amounts to pose a health risk to humans, but it can affect flavors in foods and processing performance. Human food products are restricted to a 1-ppm level established by the FDA. This level is considered safe for human consumption. The food industry often sets standards that are more restrictive. DON causes feed refusal and poor weight gain in some livestock if fed above the advisory levels. FDA advisory levels are as follows:
1 ppm: Finished wheat products, such as flour, bran and germ that potentially may be consumed by humans. The FDA does not set an advisory level for raw grain intended for milling because normal manufacturing practices and additional technology available to millers can substantially reduce DON levels in the finished wheat product. However, individual millers or food industries may have stricter requirements than 1 ppm.
10 ppm: Grains and byproducts destined for ruminating beef and feedlot cattle older than 4 months and for poultry, providing that these ingredients don’t exceed 50 percent of the diet.
5 ppm: Grains and grain byproducts destined for swine, providing that these ingredients don’t exceed 20 percent of the diet.
5 ppm: Grains and grain byproducts destined for all other animals, providing that these ingredients don’t exceed 40 percent of the diet.
Taken from NDSU Fact sheet PP-1302, DON (Vomitoxin) in Wheat. http://www.ag.ndsu.edu/pubs/plantsci/pests/pp1302.pdf

From “Head Scab and the Relationship to Saved Seed and Vomitoxin Production.”  June 10, 2011.  Bob Mulrooney, Extension Plant Pathologist, UD.

Scabby Wheat Seed

July 6, 2009 in Uncategorized

With high levels of scab this year in wheat, the question is whether or not the seed can be saved. Scab infected seeds can lead to seedling blights if planted. If wheat has scab and is to be saved for seed, it needs to be cleaned very well and then treated with appropriat fungicides. The following is information on dealing with scab infected wheat to be saved for seed.

Head scab can create an issue for wheat intended for seed. The first priority is to separate the seed lots with the worst damage from those with less damage. Use the best quality grain to meet your seed needs. Plan to clean the grain heavily to remove the damaged kernels. Commercial seed cleaning equipment should be able to remove most of the diseased kernels, because the diseased kernels are smaller and lighter in weight than the healthy kernels. The first level of cleaning for scabby wheat should be screening and aspiration. This is the primary cleaning method, and can take out much of the lighter-weight, scabby kernels, depending on the level of cleaning desired. The limitation of this method is that quite a bit of non-scabby wheat may also be removed, resulting in very high cleanout rates in some cases. Another option is to have the grain cleaned with a gravity table. Fewer seed cleaning operations have this equipment, but it can be very efficient at removing light-weight kernels. A gravity table will take out low-test-weight wheat with relatively low cleanout. After cleaning to increase the test weight to at least 56 lbs per bushel, and germination to at least 80 to 90 percent, the grain can be used as seed if desired. This seed should be treated with a fungicide seed treatment, however, since the scab fungus can also cause seedling blight the following growing season.

Fungicide seed treatments for scab control.

Information from Kansas State University http://www.agronomy.ksu.edu/DesktopModules/ViewDocument.aspx?DocumentID=2076 Table from the Ohio State University.

Review of Restrictions on Saving Seed

January 13, 2009 in Uncategorized

I recently participated in a discussion on the use of non-GMO soybean seeds that can be saved by the producer to replant the following year. Farmers are concerned about the high cost of seed and are looking for ways to reduce production costs. I came across a good article on the subject from the Ohio State University and though I would share it with you.

Saving soybean grain harvested in 2008 for use as seed in 2009 is unlawful except for a few varieties, most of which are older and lower yielding than more recently released varieties. Many of these are non-Roundup Ready public varieties. The Federal Seed Laws and Utility Patents prohibit saving the grain of varieties they protect. The seed of most soybean varieties currently on the market is protected by either the Federal Seed Laws or Utility patents. Following is a description of soybean variety protection laws.

The principal incentive for the development of new varieties is being granted the genetic developers for the exclusive right to reap the financial rewards of that effort for a number of years. There are two types of protection by which variety developers can protect their varieties from misuse and profit from the development of a new variety. These methods of protection are the certificate of plant variety protection granted under the Plant Variety Protection Act (PVPA) and by a Utility Patent.

The Plant Variety Protection Act:

This act was developed to promote the development of new varieties. It allows plant breeders to determine who can sell seed of their new variety, which allows them to recoup the funds expended in develop. This system provides farmers with a continuous stream of improved varieties with increased yield potential and resistance to insects and diseases, and improved adaptation to various growing environments.

The Amended Plant Variety Protection Act became effective April 4, 1995, and covers most crops except hybrid corn, and prohibited the following four activities without the authority of the varieties’ owner:
a) Selling or offering a protected variety for sale.
b) Sexually multiplying the variety as a step to marketing it for seeding purposes.
c) Using seed marked or labeled “propagation prohibited” to grow the variety.
d) Dispensing the variety to another person without telling that person the variety is protected.

Seed protected under this law must be sold by its’ variety name (except for turf, forage crops, alfalfa and clover). A producer who has obtained the seed with the authority of the owner may use the seed for growing a crop and save the seed that results from that crop for his/her personal use. He/she may not sell this reproduced seed to a second producer.

Title V: This option of variety protection allows for the sale of seed by variety name only as a class of certified seed. Non-certified sales are prohibited. Seed may be called “Certified” only after meeting all the requirements and standards of an Official Seed Certifying Agency, which in Delaware is the Delaware Department of Agriculture.

Utility Patents:

Utility patents are a means of protection for varieties with special characteristics, especially those developed through genetic engineering although there are non-GMO varieties also with patents (especially food grade varieties and specialty soybeans). Examples include Roundup Ready and Glyphosate Tolerant varieties and hybrids, Liberty Link varieties and hybrids, Yield Guard Plus, Hercurlex, Clearfield Hybrids, etc.

Adapted for Delaware from “Understand the Seed Laws If You Saved 2008 Grain for Seeding in 2009″ by Jim Beuerlein in the January 6-21 issue of the Crop Observation and Recommendation Network newsletter from the Ohio State University.

Plant Protection Act, Patented Seed, and Saving Small Grain Seed

August 25, 2008 in Uncategorized

The following is more information on saving small grain seed, the plant variety protection act, and patented seeds.

The Plant Variety Protection Act provides developers of new varieties of plants patent-like rights that protect the reproduction and distribution of their varieties.

Varieties that are protected under the Plant Variety Protection Act can be sold as seed stocks only with permission of the certificate holder and in some cases, only as a class of Certified seed.
Varieties that are protected must have labels on the seed containers indicating the type of protection.

Farmers may save a limited amount of seed for replanting, but cannot sell it to anyone without permission of the owner.

Identifying Protected Varieties

It is the responsibility of the seller to inform the buyer if a variety is protected. Seed containers should be labeled indicating the type of protection for which the owner has applied. If the owner of the variety has chosen to sell either uncertified or certified seed, the label should state “Unauthorized propagation prohibited–U.S. protected variety.” This statement, or others similar to it as defined in the act, is sufficient notification of protection. If the seed is purchased in bulk, the appropriate statement should be printed on the bulk sales certificate.

Exemptions Under the Act

The amended PVP Act allows for only two exemptions, 1) a farmer’s exemption allows for saving a quantity of seed for the sole use of replanting on the farmer’s land an area no larger than the area that was planted to the original seed purchased. Sale of any quantity of seed protected under the amended act is prohibited; and 2) a research exemption allows for the use of protected varieties or plant parts for breeding to develop a new variety.

Some commercial wheat varieties are now available in the United States that are patented. A variety may also receive double protection from patent and plant variety protection. PVP and patented are two distinct categories. No one can replant a patented wheat variety for any reason.

Information from Colorado State University and Mississippi State University.