Michigan Tomatoes in danger from late blight?

by Grace Dannemiller, Agribusiness and Applied Economics major

What is Late Blight?

Late blight is a pathogen that affects green and ripe tomatoes when the weather is cool and humid by blighting the part of the plant that is visible. Late blight is most commonly found in potatoes, but is also having a major impact in the tomato industry.

How does it survive?

The pathogen survives primarily from infected abandoned, volunteer, and culled tomatoes. Late Blight can easily be dispersed by the wind and can infect a large area in a short amount of time. Once a plant is infected, it must be culled to prevent the disease from spreading to neighboring plants.

How can it be prevented?

Studies done at Michigan State University have been testing fungicide products to manage late blight. Results of these tests have shown a nearly 66% decrease in the diseased leaves as a result of treatment. In addition, the treatment also reduced the amount of rotted fruit.


As the test above has shownn with treatments the disease can be managed quite well if applied following recommended guidelines. It is important to be aware of what diseases are happening around your area so that you can start treatments before the disease runs its course. Late Blight products that could be used for prevention include Ranman, Revus, Gaval, and many more (Late blight threatens Michigan tomates).

To learn more please visit Michigan State University’s website:

This blog post was an assignment for Societal Issues: Pesticides, Alternatives and the Environment (PLNTPTH 4597). The views expressed are those of the author and do not necessarily reflect the views of the class, Department of Plant Pathology or the instructor.

Leave a Reply

Your email address will not be published.