Just in Time Basics for Spraying Folicure or Proline

The wheat that survived the winter with sufficient stand to make it to harvest is close to heading if it hasn't headed already. If your wheat has already been in head for a week, you can elect to skip this article. For those of you who are still anticipating wheat head emergence - this information is for you. There are a couple of things you have to keep in mind. Application of Folicur or Proline requires specialized nozzles or nozzle combinations to do the best job of spray coverage of the wheat heads. The second is that the wheat which has not yet headed out will likely do so within the next week or two. Third, nozzles to apply these two fungicides are in short supply due to vigorous demand.

How to Maximize Spray Coverage of Wheat Heads

The key to applying these fungicides to prevent Fusarium Head Blight (FHB) is to spray all sides of all wheat heads with product. Heads that are missed or heads that are only partially sprayed are prone to infection with FHB. Research carried out at University of Guelph - Ridgetown Campus, since 2001, has evaluated spray nozzles and nozzle combinations to maximize spray coverage on all sides of the wheat heads. The results show an interesting trend. The closer the nozzles sprayed to horizontal, in a forward and back manner, the better the spray coverage. Nozzles that spray close to vertical in the wheat had significantly less spray coverage on the heads. Spray that doesn't hit the wheat heads is not there to protect the wheat heads against FHB. The following diagram shows a boom end view of the recommended nozzle orientation of a forward and back double nozzle assembly. Turbo FloodJet nozzles alternating forward and back every 20" along the boom also have this 15° below horizontal spray inclination. This is what puts these two nozzle setups at the top of the spray coverage ladder for Folicur and Proline.

Water Volumes

Follow label directions regarding water volumes. More water should improve spray coverage, especially in windier conditions. For ground application keep water volumes up in the 18 to 20 GPA range. Do not exceed 20 GPA application rates.

Spraying Speed

Numerous years of testing at Ridgetown have shown that spray coverage levels are very near equal whether you spray at 6 MPH or 12 MPH. Travel speed did not change the ranking of the different nozzles. The best nozzles spraying at 6 MPH were the same nozzles that were the best spraying at 12 MPH. Spraying speed does not appear to be a critical factor in spray coverage levels on wheat heads.

Figure 1. Nozzles with a shallow attack angle, like forward and back double nozzles and alternating turbo floodjets, have significantly better spray coverage of wheat heads than nozzles spraying straight down.

Nozzle-to-Target Distance

Forward and back double nozzle assemblies and alternating Turbo FloodJets should be operated at 10 to 12" above the wheat heads. TwinJets, TwinCaps and other flat fan nozzles should be operated a sufficient height above the heads to allow full pattern development, usually about 20". If you operate your nozzles higher than this minimum nozzle-to-target distance, spray coverage on the heads will be significantly reduced. Operating the boom at double the minimum nozzle-to-target distance from the wheat heads could reduce spray coverage by as much as 50%.

Application Timing for Folicur & Proline

Day 0 is when 75% of the heads on the main stems are emerged.
Day 2, the most preferred timing to maximize protection against Fusarium is when flowering starts, anthers visible only in the middle of the head/50% of the heads in flower.

Rain Fastness

Folicur and Proline are both rainfast in one hour. Wheat heads should be fairly dry before spraying is carried out. Moisture droplets on the heads may cause spray to run off thereby reducing coverage levels.

Sprayer Cleanout before Spraying Wheat

If you don't do a good job of cleaning out your boom and sprayer you will know soon enough. If that damaged field is beside the road - so will everybody else. THOROUGHLY clean your sprayer and boom both inside and out. I'm not going to go through the routine except to say if it takes you 10 minutes or less - it's likely not thoroughly cleaned.

DONcast Maps

Only site-specific DONcast maps are available this year from Weather INnovations Inc (WIN). This free service has been made possible by sponsorship from the Ontario Wheat Producers' Marketing Board and Bayer CropScience. Visit the WIN website at www.weatherinnovations.com and follow the prompts.

Figure 2. This Wheat head is at Day 2.

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