As growers, we can tend to focus on the insects, weeds and diseases that are causing visible damage to our crops as it occurs. We sometimes forget there can also be yield-robbing pest threats quietly eating away at our profits out of sight below the surface. One such “invisible” pest afflicting sugarbeet growers is the sugarbeet cyst nematode (BCN).
The number of fields with confirmed BCN presence has grown drastically over the last 30 years, and the pest has become increasingly difficult for growers to manage. These microscopic parasitic roundworms have the capability of causing extensive damage such as reduced stand, stunted beet growth and decreased root efficiency, all of which can lead to yield losses up to 80 percent. The battle against BCN is fought with proactive management practices beginning at seed selection time.
Symptoms and Management:
BCN overwinters in soil and infects sugarbeets at the tips of their roots in wet conditions during the spring and continues to thrive during summer. In ideal conditions, nematodes will continue to reproduce until the food supply is exhausted. Due to the parasite’s unique reproductive cycle, the eggs can remain dormant in the soil for many years within the cyst making the infestation a serious threat for seasons to come.
While above-ground symptoms are rare, growers may see indications of sugarbeet cyst nematode during the growing season, including:
- Stunted plant growth
- Wilted plants
- Yellow leaves
- Hairy or “bearded” sugarbeet roots
- Forked appearance
- Opening in root surface
In areas with a history of nematode presence, “Michigan State University Extension Sugarbeet Advancement” recommends that sugarbeet fields be soil and root tested for the presence of BCN throughout the growing season. The effects of BCN on plant growth may be most apparent during periods of hot temperatures or where soil moisture is limited when the leaves of damaged plants wilt. Special attention needs paid to these areas when looking for the presence of BCN. Plants exhibiting nutrient deficiencies (i.e., nitrogen) are also indicators that nematodes may be present.
“Although it is impossible to completely eradicate BCN from a field once it has become established, there are many management tactics growers can implement to help reduce and control the population,” said David Belles, Seedcare technical product lead for Syngenta. “We recommend growers test soils for BCN; select a BCN-tolerant variety treated with a seed treatment nematicide; and rotate fields with a non-host crop like wheat, corn or alfalfa.”
Protect Your Crops from the Start
Syngenta introduced several new nematode-tolerant Hilleshög brand sugarbeet varieties for the 2015 season. These varieties are being offered to growers in areas where nematodes pose a significant threat to crops. To further enhance protection against BCN, Syngenta offers Clariva pn seed treatment nematicide on select nematode-tolerant varieties in areas with heavy nematode pressure for 2015 planting. It can also be used in conjunction with CruiserMaxx Sugarbeets insecticide/fungicide.
Belles said, “It’s important to keep in mind that BCN-tolerant varieties do not completely eliminate the feeding and reproduction of the nematode, and alone may not be enough to offset BCN’s impact on sugarbeet yield. Clariva pn combined with BCN-tolerant varieties could prove to be an important strategy to help maintain their effectiveness.”
In addition to choosing the best-suited variety and seed treatment for a field, soil testing and scouting regularly throughout the season to monitor for signs of BCN damage is a must. Local seed agents and agronomists can provide recommendations about timely crop management, too.