2017 Cercospora Resistance Maps

Map 1 – Eminent/Minerva by township
Eminent/Minerva resistance levels remain high throughout the RRV, resistance levels have leveled off yet, mostly, with a slight increase in resistance over the 2016 maps in comparison, with moderate to high resistance overall, and some Hillsboro and Moorhead District townships and a handful of others with very high resistance to take note of. Eminent/Minerva is strongly recommended to only be used as a tank mix partner with another non-Triazole fungicide. Not more than 50% of total applications per year should include triazoles. Contact your Agriculturist for information on a section by section basis.

Map 6 – Headline/Priaxor by township
About 85% of townships in the Red River Valley with sugarbeets, now exhibit severe resistance to Headline/Priaxor with severe rated resistance infiltrating all five factory districts. Overall, 2017 shows a moderate increase in resistance compared to 2016 when comparing maps. It is strongly recommended Headline/Priaxor applications be preceded by fungicides with other modes of action to reduce concern from fields where resistance has been documented. The best timing for this application remains to be the last week of August through the first week of September for sugarbeet root frost protection/recovery and plant health benefits. If used for application, Headline/Priaxor MUST be tank mixed with a full rate of each product in the tank mix, NEVER use these products without a tank mix partner. Contact your Agriculturist for information on a section by section basis.

Map 8 - Inspire by township
Inspire resistance levels have increased from moderate to high levels throughout the RRV from the 2016 maps in comparison, however with only 2 townships with very high resistance to take note of. Inspire is strongly recommended to only be used as a tank mix partner with another non-Triazole fungicide. Not more than 50% of total applications per year should include triazoles. Contact your Agriculturist for information on a section by section basis.

Map 13 - Proline by township
Proline resistance levels are overall moderate to high throughout the RRV, with a general band of very high resistance located in the Hillsboro District and some scattered townships in Eastern Drayton District to take note of. Proline is strongly recommended to only be used as a tank mix partner with another non-Triazole fungicide. Not more than 50% of total applications per year should include triazoles. Contact your Agriculturist for information on a section by section basis.

Map 18a - TPTH (Tin) by township
This is the traditional TPTH map using original resistance level scale from 0-100 ppm and separated into only 2 resistance categories. About 90% of townships exhibited Tin Resistance in 2017. Overall, resistance to Tin increased again when comparing the 2017 map to the 2016 map, however rapidly in the Drayton and Hillsboro Districts and going south into the eastern Moorhead District. Tin should be utilized as a tank mix partner with other chemistries, at full rates of each tank mix partner. Contact your Agriculturist for information on a section by section basis.

Map 18 - TPTH (Tin) by township (New Map Version)
New map format, including same data as map 18a with the same 0-100 ppm scale, however, separated into 5 categories of resistance for further resolution compared to the traditional map 18a. The map indicates moderate TPTH resistance from Moorhead District going north to East Grand Forks District, and then decreasing generally to slight resistance in the Drayton District. High resistant townships are scattered on the east, west, and south borders of Moorhead district along with 2 townships in Drayton District and 1 in the Crookston District. Even though the map appears to be less resistant compared to the traditional map, Tin should be utilized as a tank mix partner with other chemistries, at full rates of each tank mix partner. The goal of the map was to show more details of resistance levels for continued BMP’s (Best Management Practices) of TPTH use. Contact your Agriculturist for information on a section by section basis.

Map 19 - Topsin by township
This is the 2016 report map. The Topsin data for this map is reported every other year (even years). Data will be again collected and reported for the 2018 crop. The percent of isolates resistant to Topsin remain to be low to average overall, with a few scattered high to only one township having very high resistant isolates. Topsin is NEVER recommended to be applied alone. Topsin with a suitable tank mix partner remains to be a good choice, just not as the first application of the year. Remember Topsin PHI is 21 days, so plan harvest accordingly around your spray rotation.

General Comments
2017 was a welcomed year for an overall decrease in CLS pressure. Pressure was overall lower at the beginning of the year and finished low with drier environmental conditions as the year progressed. Continued diligent CLS management is highly recommended to aid in reducing overall CLS inoculum. Tank mixes continue to be a necessity, and not considered optional at this point with high resistance present. 15-20 gallons per acre water, 80+ psi, starting spray program earlier and 14 days maximum spray interval are all needed practices with current CLS conditions. Glyphosate applications must be separated from fungicide applications as water volumes vary by targeted pest. 

Additional information is available from your Agriculturist. Another useful website is www.sbreb.org for the latest in North Dakota State University and University of Minnesota research information.