What’s best — fungicide by air or by ground?

With all the science touted within modern agriculture, it’s amazing how many simple questions are not easily answered.

For instance, what gets the best bang for your buck — fungicide applied by air or fungicide applied with a ground rig?

Aerial applicators are quick to point at the advantage of no tracks in your field, and that’s certainly a strong argument. Depending upon tire width, trampling can easily account for two to three percent of the area covered. When you take the turns into account, it’s even higher.

Three percent of a $300 an acre crop is $9 an acre, which might be what an aerial applicator charges. Presto, the argument that aerial application pays for itself simply by saving tracks.

In a crop that might be worth $500 or $600 an acre, it would seem to be a no-brainer. Call in the aerial applicator and park your sprayer.

But is all the trampled area a complete loss? It depends on the crop stage.

Spray tracks early in the growing season may be scarcely visible by harvest time. On the other hand, later applications leave less time for damaged plants to recover and adjacent plants to fill in the space. Sprayer tracks can also lead to harvest difficulties.

It would be interesting to see yield comparisons on ground rigs spraying nothing but water on various crops at various stages as compared to no field trampling.

In many cases, when three percent of the field area is trampled, it probably means much less than three per cent yield loss, but actual research results seem to be lacking.

There are also instances where more than one fungicide application is needed, and the same ground rig tracks can be followed each time.

However, do tires rolling through the crop canopy contribute to disease spread?

Speaking of research, is aerial fungicide application as effective as ground application? Opinions abound, but no one quotes any comparison studies.

In fairness, with so many variables, a great deal of work may be required to reach valid conclusions.

How dense is the crop canopy? How close to the ground does the spray plane travel? What fungicide? What crops? Adding to the complications, yield losses from disease can be highly variable.

Fungicide use has expanded dramatically over the past decade, but so has the ownership of high clearance sprayers. Everyone is aware that running a sprayer carries a cost, but fuel is the only immediate cost that comes out of your pocket.

Because producers have made the sprayer investment, they want to use it. Plus, there’s a lot to be learned about a crop from the seat of a sprayer.

When producers can’t keep up with their fungicide applications or when there’s an outbreak of insect pests, aerial application services can be overwhelmed.

This makes for a difficult business model. It’s tough for them to know how many acres to plan for in any given year.

The ground versus air debate has been around for years. In the absence of scientific comparisons, discussions will continue in coffee shops and on social media, but the arguments will be based on opinions and impressions rather than data.

It’s an important issue that doesn’t seem to get much research attention. That’s unfortunate for an industry that prides itself on scientific advancement.

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