Tomato problems and the Master Gardener classes

This year has been hard on tomato plants everywhere.

Not only are small domestic gardeners having trouble; so are large commercial producers. It was confirmed last week that we have late blight on tomatoes in this state.

This blight is worrisome because we are one of the nation's biggest producers of tomatoes. The Northeast United States has been dealing with this problem for years; however, this year late blight struck earlier than expected.

For many homeowners it is depressing to see all their hard work die in a few days when this disease has infected the plants. Late blight isn't the only disease that can cause trouble, there are many other diseases affecting other garden fruit and vegetable plants.

Why does it seem that diseases are more prevalent this year?

There is a concept called the "disease triangle" that helps explain what has to happen for a disease outbreak to occur.

The three parts are pathogen, host and environmental conditions.

A pathogen is the agent that causes the problem. For example, a fungus causes late blight. The fungus, however, can lay dormant in the soil or on a plant for a long time not causing any problems until the other parts of the triangle are present.

The host is the plant that is susceptible to the disease. For example, late blight likes tomato and potato plants, but doesn't really like any other vegetable plant.

Pathogens tend to really like a specific host. That means that we can be reasonably sure that the late blight on your tomatoes will not be passed on to your green beans.

The environmental conditions have to be favorable for the pathogen to infect the host. Each different pathogen likes different conditions. For example, late blight likes cool, wet, and humid conditions -- exactly like the conditions we have had most of the summer.

When you get the right pathogen, host, and environmental conditions disease can occur. Just remember, you need all three things to come together.

I also found it interesting that the current late blight disease problem isn't limited to just large commercial producers. We are seeing this problem in many small gardens, too.

The question that has to be asked is, "Why is late blight so widespread and where did it come from?"

I think part of the problem is that this disease might have come on transplants that were bought in the spring and planted in local gardens. It is important when buying transplants in the spring that only healthy, dark green plants are chosen. Some garden centers are not as conscientious as others and will leave diseased plants on their shelves.

These garden centers should be avoided when you are looking to purchase any plant material. I would suggest that you go to a locally owned garden center where there are people you can trust to sell you very high quality plants.

If you're not sure about the place where you are buying plants, ask the proprietor some questions. Don't be afraid to ask. Most locally owned garden centers are more than happy to answer any questions you might have about their plants. Conversely, if no one can or will answer your questions, don't buy their plants.

Many homeowners have expressed their frustration with their dying plants. If you have plants that you suspect have diseases, you should pull up the plants and dispose of them. Do not put them in your compost pile. Contaminated compost might cause more disease problems next year.

Don't burn the diseased plants either. Many times the spores of fungus causing the diseases can survive very high heat and could spread the disease through the air to your neighbor's plants.

Despite the problems that can occur, gardening is a wonderful hobby. If you want to be a little greener and start gardening or you just love to garden and want to know more, I would like you to consider enrolling in the Master Gardener class this fall.

A new Master Gardener Class will be starting on Aug.18. I want to invite all the people that are interested in becoming Master Gardeners to contact me soon so I can set aside a place for you in the class. We have a few places left in the class and want to get them filled.

The purpose of the Purdue Master Gardener Program is to teach people more about growing plants and to more effectively extend information related to plants. To be part of the next series of Master Gardener classes please contact the Putnam County Extension Office and say that you are interested in the Master Gardner Class.

You will have to complete an application form and return it to the Putnam County Extension Office.

The classes meet every Tuesday night from 6-9 p.m. The classes will last 12 weeks from Aug.18 to Nov. 3. The cost is $75.

Family rates apply. If you have any questions or would like more information, Please contact Ann Delchambre at 653-8411 or e-mail adelchambre@purdue.edu