Tar Spot Disease: Treatment Tips That Actually Works 100% - June 2023

Tar Spot Disease: Treatment Tips That Actually Works 100%

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By Samuel Ansah

Last Updated December 31, 2022

You want to produce a bumper crop of corn this year, but the tar spot disease seems to have destroyed all hope. It could seem impossible to make up for the loss resulting from the damage caused by the disease.

This type of unusual event puts farming among the high-risk industries to invest in. You shouldn’t worry, though. This article includes practical advice from farmers who have successfully fought the tar spot disease.

Tar Spot Disease

What is tar spot in corn?

Tar spot disease in corn was discovered first in Michigan in 2016 caused by Phyllachora maydis. With the formation of black spots, the fungus causative agent produces spores within the stroma. The severity of the disease can be high and can have a great impact on crop yield.

Tar spot corn 2022

Is this a disease that will kill people? Perhaps not. A full report on Tar sport surfaces in the Midwest’s corn harvest. Among the states reporting tar spot corn symptoms in 2022 are Iowa and Columbia.

Tar spot symptoms

You must first be aware of typical tar spot symptoms before you can take any action that you could consider to be an infection. Tar spot is different from other infections, but it is most frequently confused with insect frass and corn rust infections. The symptoms of tar spots are listed below.

How do I identify tar spot?

  • Hard lesions
  • 1/16 to 0.75 inches in diameter raised spots
  • Formation of lesions on the upper side
  • Rust spot forms in the leaf

What is the difference between tar spot and insect frass/rust spores?

Tar spots may resemble insect frass and rust spores in appearance, but the difference between the two is that although insect frass and rust will wipe off when moisture falls on the leaf surface, tar spots won’t since they form within the stroma.

Best fungicide for tar spot in corn

Low-risk area1 spray of Trivapro at VT/R1 (Tasseling and milking stage)
Early infection of tar-spot infection2 sprays of Trivapro at V4 to V8 timing and VT/R1
Fungicide for controlling tar spot disease

When to spray for tar spot in corn?

The best latent period to beat the tar spot disease is between 14 and 40 days. Typically, plants become infected before exhibiting symptoms.

How to stay a step ahead of tar spot

Knowing if you have ever had a tar spot is your first line of defense. This can let you know whether there are any local inoculum sources that can start infections. If you have previously observed a tar spot on your farm, then ipso facto the pathogen is present and near the corn.

Additionally, studies show that the tar spot disease can grow in a particularly favorable environment made possible by the weather. So how do you know when to watch the weather?

Tar spot Tracker

To stay alert and ahead of tar spot you may need the following integrated tar spot tracker.

Field Prophet

In agronomic fields or turf settings, Field Prophet helps in making management decisions concerning current or impending disease infections like tar spot. The algorithms in the app employ statistical models in conjunction with weather data for dates that the user has chosen to predict the likelihood that plant diseases will arise.


Tarspotter uses GPS data to detect whether the weather has been conducive to the growth of Tar spot fungus. The app’s models take advantage of the local weather to forecast ideal circumstances for the majority of corn-growing locations. A site-specific risk prediction is created using these forecasts and crop phenology. Download on Apps Store and Google Play Store.

Source: PoultryABC.com
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