Time to sample sugarbeet fields for sugarbeet cyst nematodes

Best time to sample for sugarbeet cyst nematodes in growing sugarbeet fields is mid-summer to late fall.

A random survey conducted in 2007 by Sugarbeet Advancement and Michigan Sugar Company found about one out of four sugarbeet fields had detectable levels of sugarbeet cyst nematodes. Research has indicated that heavy infestations can reduce yields up to 15 tons per acre and low infestations can range from two to four tons with no visible symptoms. The economic impact to the Michigan Sugar Cooperative for yield reductions of just one ton per acre is over 10 million dollars annually. For this reason, every sugarbeet field in Michigan should be checked for this pest.

Michigan Sugar Company has implemented a program to pay the cost for sugarbeet cyst nematode testing for sugarbeet growers. The goal is to test all sugarbeet fields in the next four years for this pest. Nematode-infested fields can then be targeted for nematode-tolerant varieties. Current sugarbeet fields should be sampled in late summer to properly diagnose sugarbeet cyst nematode infestations. Because of the patchy nature of this pest, this method is the most successful in finding nematodes because reproduction will increase populations by late summer.

Sampling can also be done in the fall for fields that are going to be planted to sugarbeets in 2013. This timing is not as accurate as sampling an existing sugarbeet field and will often give false negatives. To minimize the number of false negatives, it is recommended that 25 soil cores be taken per tested field. Samples can be taken with a soil sampling tube, probe or shovel. Samples should be taken when soils are not excessively wet, dry or frozen. Samples taken from current sugarbeet fields should be probed near the beet plant and always include some root hairs to help with identification of nematode type. Soybean cyst nematodes will not live on sugarbeets. Probing where tare dirt is commonly dumped and the margins of weak areas will increase the chance of finding the pest if they are present.

Approximately one quart of soil can be placed in a durable, moisture-resistant sample bag. One gallon baggies will work very well. Keep samples cool, ideally 50 degrees Fahrenheit; do not leave the bag in direct sunlight or car trunk. Samples should be labeled with information including location, soil type, cropping history and current crop. This information will aide in the diagnosis and identification of either soybean or sugarbeet cyst nematodes. Remember, samples should not be dried out and need to be kept cool!

Samples can be delivered to your Michigan Sugar Agriculture office to be forwarded to the Michigan State University Diagnostic Services lab. For more information, contact your Michigan Sugar Company Agriculturist or REACh Research Team.

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