Sevin as ‘cure all’ is common mistake

Q. I have mold on my marigolds. I‘ve been spraying them with Sevin but they aren’t getting any better. Can you tell me what I can do next?

Caroline from Boardman

A. Caroline’s use of Sevin as the “cure all” in the vegetable garden is a common mistake.

Although common, it is still a mistake and should be avoided.

Please know that Sevin is not a cure for all issues in the vegetable garden.

Caroline’s marigolds have a mold, which is a fungus.

One of the options for dealing with fungus is the application of a fungicide.

Sevin is an insecticide and has no effect on fungi.

Her reaction to finding a quick solution to her marigold problem is understandable, as we all want to do something about a problem as soon as we can.

But, spraying a chemical product should be the last control method attempted.

Before listening to a neighbor or doing something in a hurry, be sure to read the product label to know what the spray intended to control and how it is to be used.

Caroline’s question brings up an important point about disease and pest management.

The first thing to do when a problem is found is to identify the cause.

In this case, there could be many reasons why the marigolds have fungus – overcrowding of plants, use of old cultivars that have little resistance, the planting site could have too much shade, and so on.

Once the cause is known, then the lease toxic remedy should be tried first.

This approach is part of a disease and pest management strategy used by universities and extension offices across the country called Integrated Pest Management.

IPM is used to solve disease and pest problems while minimizing risks to people or the environment.

If you cannot tell what is causing a problem in your yard or garden, you can bring a sample of the problem to the Mahoning Extension Office Clinic and we can work through the problem with you.

As for the mold on your marigolds, without a sample I cannot tell you which type of fungus is causing the problem.

But good cultural practices may be all your marigolds need to overcome the fungus.

Start with sanitization. Remove any dead or dying plants and cut off any infected leaves on plants you think can be saved. Remove all this material from the area and throw it away.

Monitor the surviving plants to see if they improve.

And if you do need use a fungicide, be sure to read, understand and follow all directions on the label.

Here is a link to common molds on Marigolds: http://go.osu.edu/marigoldproblems.

For details on safe and effective use of sprays (both organic and synthetic), go to http://go.osu.edu/pesticidesafety.

Today’s answer is provided by David Sprague, OSU Extension master gardener volunteer. Call the office hotline at 330-533-5538 to submit your questions. Regular clinic hours are 9 a.m.-noon Mondays and Thursdays.