How to reduce impact of early tomato blight

Q. What’s wrong with my tomato plant? Is it a wilt disease? Will it have fruit this year?

Betsy from Liberty (and many more)

A. Oh, the glorious tomato! It seems to get some kind of disease each year. Thankfully, it continues to push through and give at least two sets of fruit each year.

Although somewhat easy to grow, tomatoes seem to have a couple of issues each year. Most issues show signs on the leaves early in the season before fruit ripens.

The most-common problem we see here in Mahoning County is early blight. We see it every year.

This disease makes lesions with concentric circles on the lower leaves, then progresses up the plant. The disease is spread many ways, but mostly by water splashing the disease up the plant during rain events and watering.

This year, we’ve seen some of this, but not an abundance due to the dry conditions.

Here are my tips for reducing the impact of early blight on your tomato plants:

Space plants and stake them. Tomatoes need at least 24 inches between plants in the row. Overcrowding decreases air circulation through the plant, allowing moisture to remain on the leaves longer in the morning. Use individual stakes or adopt the “Florida weave” method of tying to use less stakes. Either way, get them up off the ground to increase air circulation and help them dry off faster in the morning.

2. Water low to the ground. Use soaker hoses or drip irrigation under some type of mulch (newspapers, straw, etc). Another alternative is a bucket or milk jug with one tiny nail hole in the bottom. Fill the container and let the water seep directly into the root zone. If you must use a garden wand, be sure to water right on top of the ground so the water filters down to the roots. Do all you can to avoid wetting the leaves.

3. Sucker and prune your plants. Taking out the “sucker” between the main stem and the leaf will help speed up fruit production. It also reduces foliage to increase air flow through the plant. Removing (pruning off) the lower branches of the plant will increase air flow as well.

The other major problem we expect to see this year is not a disease, but a disorder: blossom end rot. This disorder shows up in certain varieties, being more prevalent in determinate and roma cultivars. Despite what you may read on the Internet, the best way to avoid blossom end rot is to ensure your tomatoes get 1 inch of water per week.

We encourage you to water in the morning to allow more time for plants to dry, if needed. If you are using efficient watering practices, you can water later in the day.

If you use a soaker hose, you can put a tuna can under the hose to know how long it takes to apply 1 inch of water. There are watering timers available to help you do this watering during the week.

As fruit begins to set, the plant will need 1.5 inches of water each week.

You can learn more by signing up for our midsummer tomato management class at http://go.osu.edu/tomato. Or, you can learn more through our OSU Extension tomato fact sheet at http://go.osu.edu/tomatoes.

Eric Barrett is OSU Extension educator for agriculture and natural resources in Mahoning County. Call the office hot line at 330-533-5538 to submit your questions. Regular clinic hours are 9 a.m. to noon Mondays and Thursdays.