Cercospora Leafspot (CLS) fungicide recommendations incorporate both CLS control and resistance management.
Tank-mix and rotate fungicide modes of action throughout the fungicide program.
Each recommended fungicide tank-mix combines 2 different modes action utilizing a translaminar/systemic fungicide paired with a contact fungicide.
- Exception is when EBDC is alone in the 5 & 6 spray programs
- There is no documented resistance to EBDC fungicides
Monitor CLS Daily Infection Values (DIV’s)
- The Crystal Agronomy App is no longer supported
- NDAWN Mobile-Friendly Website will now be used
- 2-day DIV Risk Ratings
- 1 – 3 = Slight
- 4 – 6 = Moderate
- 7 – 14 = Severe
Starting your Cercospora Leaf Spot Spray program:
If you think you’re spraying too early, you’re probably right on time.
- Both CR+ and Non-CR+ varieties require timely initial fungicide applications.
- The timing of the 1st two fungicide applications is most important to achieve optimum potential in CR+ varieties.
- There is a robust amount of Cercospora inoculum in the environment from the late onset of Cercospora in the 2021 growing season.
- Start fungicide program once rows start to close coinciding with Moderate to Severe Daily Infection Value’s. Start early and stay on track.
- 2022 is a unique year with later dates and therefore later canopy row closure, be in contact with your Agriculturist on fungicide application timing.
- To note: in recent years we have observed CLS in fields without closed rows
- It can take 5 to 21 days for spots to appear on the leaf after Cercospora infects the leaf.
- Fungicides are protectants and are not curatives, use them as such.
- To limit CLS infections, be proactive by applying fungicides to protect the sugarbeet leaves before infections can occur.
RRV Initial CLS Fungicide Application and # of CLS Fungicide Applications
The below charts are compiled from data collected by American Crystal Agriculturists from growers on their Cercospora fungicide application programs from 2017 – 2021 for the Red River Valley.
• Your Agriculturist has these same charts for their factory district and their growing area. The trends are the same for these as compared to the Red River Valley.
These charts show recoverable sugar/acre and revenue/acre increase with earlier initial fungicide applications and with additional fungicide applications.
2022 ACSC Cercospora Leaf Spot Fungicide Program
Fungicide Class (Mode of Action) Information
Tips for Maximizing Cercospora Leafspot Control
- CLS variety rating – CLS control should improve with a better CLS variety rating. However, this may not equate to fewer fungicide applications.
- Daily Infection Values – Monitor Daily Infection Values (DIV’s) and weather forecasts for timing initial and following fungicide applications. Found on:
• NDAWN Mobile Friendly
- Timing of fungicide program – Start program once rows close and coinciding with Moderate to Severe DIV’s. Start early and stay on track. Cercospora Leaf Spot can appear 5 to 21 days after spore infection. Fungicides are protectants and being proactive by applying fungicides ahead of infection limits the development of Cercospora leaf spot.
- Full rates – In tank mixes utilize full application rates of each tank mix partner, following label recommendations.
- Spray intervals – The time interval between applications should not exceed 12 days, plan best as possible around adverse weather conditions (rain, wind, hail). For EBDC’s alone follow a 7-day spray interval.
- Aerial application – If too wet for ground application, stay on schedule with an aerial application.
- Glyphosate tank mixes – Are not recommend with CLS fungicide applications since optimum water volume requirements are different for glyphosate and CLS fungicide applications as the target pests are not the same.
- Pre-Pile & Fungicide Pre-Harvest Intervals – Be aware of each fungicide’s Pre-harvest Interval and how that may impact pre-pile harvest plans. Adjust your fungicide spray program accordingly.
- Water volume – CLS fungicides need excellent coverage to protect the sugarbeet leaf surface. To achieve this requires 15 to 20 gallons of water per acre.
- Pressure – High pressure applications at 80+ psi provides improved leaf coverage depending on the spray tip chosen.
- Spray nozzles/tips & droplet size – Using nozzles that will produce Medium droplet sizes of 250–350µm (microns) is optimum for fungicide applications. Utilize nozzle manufacturer’s recommended application pressure to operate within this range. Use proper spray boom height above crop canopy depending on chosen spray nozzle degree angle for best coverage.
- Tank mixes – All fungicide applications should contain more than one chemistry or mode of action (MOA). Only exception would be EBDC’s. Tank-mixing fungicide MOA’s and rotating MOA’s are paramount. Using only a single fungicide, MOA, increases resistance development pressure to that fungicide. Single fungicide applications may “get you by” but will increase and compound resistance to fungicides on your farm and surrounding neighbors. Utilizing all available fungicide chemistry wisely is vitally important for current fungicide options today and tomorrow. Any tank mix should be sprayed out as soon as possible, with agitation, do not allow mix to sit overnight, spray tank out completely, and rinse sprayer (all lines and tank) with clean water daily.
- Water temperature – Warm water is best for dissolving & mixing fungicides. Pre-warm water in dark bulk tanks a few days prior to use, sunlight aids in warming the water.
- Jar test – If in doubt about a tank mix, run a jar test to see if combination is compatible before loading sprayer.
- Scout fields –during the growing season to evaluate how your fungicide spray program is working.
Wales tank mixing order for Pesticides
- Wettable powders & dispersible granules
- Agitate tank to mix thoroughly
- Liquid flowables & suspensions
- Emulsifiable concentrate formulations
- Surfactants & Solutions