2010 Edition
The advanced stage of growth will likely lead to an early start to the fungicide season and possibly more sprays than the past two years. Three ingredients are necessary for Cercospora to get rolling. If any of the three are lacking nothing will happen. The three are:
- Susceptible host
- Favorable environmental conditions
- Inoculum present
The sugarbeet has a natural immunity early in the season. Generally the time to get concerned is shortly after row closure. For 2010 that is now for many fields so criteria #1 has been met for many fields. As you can see below environmental conditions as of late as measured by the Wahpeton NDAWN station have not been favorable for infection to take place. Just because the conditions have not been favorable does not mean infection will not take place. And last but not least the inoculum needs to be present. The past two seasons have seen little incidence of Cercospora so inoculum levels should be greatly reduced.
To spray or not to spray. We generally like to wait until we see spots in fields before firing up the sprayers. Some consultants may be pushing for an early start. We don't feel at the present time (June 23) there is any need for fungicide protection. If you do spray you are not hurting the plant but you will reduce your options for fungicide control if we do get into an active Cercospora season.
Keeping in close contact with your Agriculturist regarding the timing of your first Cercospora application.
Date |
Infection Potential |
July 29 |
Moderate |
July 28 |
Severe |
July 27 |
Moderate |
July 26 |
Slight |
July 25 |
Moderate |
July 24 |
Severe |
July 23 |
Severe |
July 22 |
Severe |
July 21 |
Moderate |
July 20 |
Moderate |
July 19 |
Severe |
July 18 |
Severe |
July 17 |
Moderate |
July 16 |
Slight |
July 15 |
Moderate |
July 14 |
Moderate |
July 13 |
Slight |
July 12 |
Slight |
July 11 |
Slight |
July 10 |
Moderate |
July 9 |
Moderate |
July 8 |
Moderate |
July 7 |
Moderate |
July 6 |
Moderate |
July 5 |
Moderate |
July 4 |
Slight |
July 3 |
Slight |
July 2 |
Slight |
July 1 |
Slight |
June 30 |
Slight |
June 29 |
Slight |
June 28 |
Moderate |
June 27 |
Severe |
June 26 |
Moderate |
June 25 |
Slight |
June 24 |
Slight |
June 23 |
Slight |
June 22 |
Slight |
June 21 |
Slight |
June 20 |
Slight |
June 19 |
Slight |
Information is for Cercospora infection potential is taken from the NDAWN web site; Wahpeton location. If you have not been to the NDAWN web site you should really take some time and look it over. Click on the link below to get there.
General Recommendations 2010 Cercospora Leafspot Season
Here are some examples of spray schedules for 2010:
Spray Program |
Application #1 |
Application #2 |
Application #3 |
Application #4 |
Two Spray |
Triazole |
Strobilurin |
--- |
--- |
Three Spray |
Triazole |
Tin |
Strobilurin |
--- |
Four Spray |
Triazole |
Tin |
Strobilurin |
Tin |
Triazoles: Eminent - Proline - Inspire XT - Enable
Tins: AgriTin - SuperTin
Strobilurins: Headline - Gem
Fungicides |
Re-Entry Interval (Hours) |
Pre Harvest Interval (Days) |
Ground Application Water Volume (Gallons) * |
Rainfast (Hours) |
AgriTin (Liquid & Dry) |
48 |
7 |
At Least 15 |
Dry on Leaf |
SuperTin (Liquid & Dry) |
48 |
7 |
At Least 15 |
Dry on Leaf |
Eminent |
12 |
14 |
5 or More |
2 |
Enable
|
12 |
14 |
Min 20 |
1 |
Proline |
48 |
7 |
Min 10 |
2 |
Inspire XT |
12 |
21 |
Min 15 |
1 |
Gem |
12 |
21 |
Min 10 |
2 |
Headline |
12 |
7 |
10 - 20 |
Dry on Leaf |
*Water by air is standard 5 gallons per acre for all fungicides.
General CLS Information:
- Inoculum spores have a 1 - 2 year survival in infected leaf debris in sugarbeet fields when left on the surface. When tillage buries the debris, most inoculum spores are destroyed in 10 months.
- Optimal sporulation, germination, and infection occur at 75 to 90 degrees with night temperatures above 61 degrees and high relative humidity.
- Other hosts for Cercospora are Red Beet, Swiss Chard, Spinach and several weed species - particularly Redroot Pigweed and Common Lambsquarter.
- Under natural infection conditions, a 3.5 KWS rating is reported to cause economic damage by reducing root yield and percent sugar (KWS scale of 1-9, with lower numbers indicating less infection).