Morning good for fungicides

Farmers who like to get out into the field early will like the early results from a study on spray timing for fungicides.

Morning looks like a better time than noon or midnight for applying them.

“So far, what we’ve seen is a trend toward the morning application being best for our fungicide,” said Alberta Agriculture crop pathologist Michael Harding.

“We’ve seen that response in two crops, in peas and barley. It’s been most dramatic in the pea crop. We haven’t really seen any significant differences in wheat or canola, but it may have had more to do with disease pressure than with fungicide.”

Farming Smarter is in the third year of a three-year study on spray timing. It is investigating results from spray applications in the early morning, at noon and at midnight. Harding talked with participants of a June 24 field school about the results specific to fungicides.

Complete results from the study have yet to be compiled, but Harding said one of the keys to preventive fungicide is proper coverage on the parts of the plant where fungus can invade.

For example, it’s most important to protect the flag leaf when preventing stripe rust in wheat, but broader coverage of the plant is required when guarding against mycosphaerella in peas.


Harding speculates that morning application might prevent fungicides from drying too quickly on plant surfaces, which allows better distribution of the active ingredients.

Dew might also help distribute the chemical. Some crops close slightly at night, which leaves the canopy more open in the early morning. 

As a result, sprayed fungicide can penetrate deeper and touch a wider area of the plant. 

The spray timing trials for fungicide were conducted on wheat, barley, canola and peas using various products registered for control of fungal diseases in those crops.

“We are seeing some differences on the fungicides,” Harding said. 

“We’re not seeing anything earth shattering. We’re not suggesting you make any life altering decisions based on what we’ve found so far, but we do see some differences, and right now the trend is indicating that morning, for many situations, could be a good time to be putting fungicides on.”