Rhizoctonia has been present in the beet crop since it was first grown in the Red River Valley. In the last 10 years most growers have observed a significant increase in not only incidence but, also severity of this disease.
Changes in cropping patterns in the Red River Valley point to even more Rhizoctonia in the future. Soybean and dry edible bean crops, in particular, increase Rhizoctonia inoculum in the soil. Corn also increases inoculum especially for one specific type of Rhizoctonia. Soybean, edible bean, and corn acres are increasing in the Red River Valley. Wheat is the best rotational crop for reducing Rhizoctonia inoculum in the soil and threat of the disease. Wheat acreage declined by more than 1 million acres since 1995, but may increase in 2008 with improved prices, Table 1.
|Source = National Ag Statistics Service - USDA|
Proper diagnosis of the disease in the field is critical. Rhizoctonia infection starting under dry conditions may look very much like Aphanomyces. Be sure you identify the specific disease carefully and know your crop history before you apply fungicides.
|Fungicide||Product/A (oz)||Approximate Lost ($)||Timing|
|Quadris||9.5 - 14.3||$20 - $32||8-12 leaf, before last cultivation|
|Proline||5.7||$18.50||8-12 leaf, before last cultivation|
The management scheme in Table 2 has proven effective in Michigan where Rhizoctonia can be very severe.
|Severity of Rhizoctonia||Variety Type||Quadris 7 - Inch Band*|
|Light||Susceptible||2/3 full rate|
|Moderate||Mod. Tolerant||2/3 full rate|
|Severe||Most Tolerant||Yes (full rate)|
|* A wider band reduces effective rate, a narrower band allows use of lower rate
From: Mr. Steve Poindexter, Michigan State University Extension
Caution: Don't mix Quadris with sugarbeet herbicides because crop injury can be very severe.
Contact your agriculturist for assistance with disease identification and to discuss control strategies.
Changing crop choices for Red River Valley farmers is one of the tougher decisions that need to be made each year. Many factors enter in to these decisions including:
Check with your agriculturist for crop rotation effects for your factory district or piler district. Local results may vary from the entire RRV data shown in Figure 1.
Recoverable sugar per acre is greatest following dry edible beans and potato. This may be in part due to the fact these crops are usually planted on soils that tend to be highly productive. Recoverable sugar per acre (RSA) following wheat and barley are very, very good even though planted on a very wide range of soil types on well over 3,000,000 acres in this 10 year period. Yields following soybean and corn are lowest. Factors that may reduce yields after soybean and corn might include:
Check with your local dealers for availability of the starter product you have been using.
Contact your agriculturist or ag office coordinator for any of these brochures.
Don't miss this opportunity to view the latest innovations. March 5 & 6 at the Alerus Center in Grand Forks
Thanks for dedicated service. Tom Zidon, EGF, Agriculturist will retire February 29, after 27 years of service to his growers.
A special thanks to Dr. Carol Windels, U of MN for pictures and use of data in this Ag Notes.