Tomato plants not up to snuff this summer? They might be suffering from one of these maladies

When it comes to great flavor, the only way to trump local produce is to grow your own.

The nutritional benefits of fresh produce are undisputable, but in my opinion the best part of growing your own produce has got to be the sheer joy of harvest. The height of tomato season is upon us and if you’re lucky you’ve been harvesting some nice-sized batches of your delicious red beauties.

Leah Blinstrub

Just recently my tomatoes started producing fruit. I’m sure my neighbors wonder about my Cheshire Cat grin and giddy laughing, but I can’t help it. Picking ripe tomatoes from my own garden is not only a tasty treat, it’s a personal achievement. They’re amazing!

To assure you’re getting the most out of your tomatoes, “Tomato” co-author Gail Harland recommends checking leaf and plant. Remember that healthy plants produce the most nutritious and best tasting fruit. Here are a few warning signs of unhealthy or diseased tomato plants from her book:

Start with the leaves

When assessing the health of a tomato plant, a good place to start is the leaves. Several common ailments can be diagnosed from the color, shape and condition of the leaves.

Early blight, bacterial leaf spot and late blight

Indication: Your tomato plant has holes or brown patches. To tell the differences between these conditions, examine the leaf for a yellow circle around the spots. If the circle is bright yellow, this is an indication of late blight. If the circle is faded yellow, this usually points to early blight or bacterial leaf spot. Here’s a good comparison of the three conditions.

Treatment: For early blight and bacterial leaf spot, remove and destroy all of the affected leaves and make sure to water the plants from the bottom, avoid watering the foliage during the process. The treatment of late blight is a little more painful; it’s best to remove and destroy all of the infected plants and check with your local garden store for a copper-based fungicide. The spray acts as a preventative measure.

Leaf roll virus, curly top virus and magnesium deficiency

Indications: Tomatoes affected by these conditions have leaves that turn yellow, curl or look distorted. Leaves that curl upward are generally a sign of leaf roll virus. The virus is caused by chilly nights but it shouldn’t impact the plant’s growth. Plants that have curly top virus have discolored leaves. Many times curly top virus can impact the growth of the plant and leave a plant growing slowly or looking small. Lastly, magnesium deficiency would produce leaves that appear yellow but have green veins.

Treatment: Leaf roll virus should resolve on its own. Treatment of curly top virus involves controlling aphid populations and destruction of the affected plants. Magnesium deficiency can be resolved by the addition of a diluted solution of magnesium sulfate to the affected leaves.

Check the fruit

Other common tomato ailments can be assessed from the condition of the fruit they produce. Tomatoes require a lot of watering. The quality time you spend watering your tomatoes provides the perfect opportunity to keep a close eye on fruit production and signs of abnormalities.

Early blight, late blight and blossom end rot

Indications: Discoloration of the tomato fruit can be an indication of any of the above conditions. The difference between late blight and early blight is that with early blight, you have discoloration on just the stalk end, while late blight features discoloration and lesions on the whole fruit. Blossom end rot is indicated by a flattening of the bottom of the fruit and browning or blackening of the bottom portion only.

Treatment: For early blight, removing affected leaves and fruit should be fine. For late blight, once again complete destruction of the affected plant is necessary. Blossom end rot can be treated with consistent watering, being careful not to get the foliage wet and sometimes adding a feed that contains soluble calcium.

Sunscald and greenback

Indications: Green or white hard spots on fruit. Both sun scald and greenback are generally caused by heat injury.

Treatment: Provide extra shading for the plants. Tomatoes need a lot of sunlight, so looking for ways to allow direct early morning sun with slight shading in the hot afternoon sun is usually preferable. Shade can be provided by adding plants/trees to block some of the sun, constructing a shade device made with nursery cloth, or with a lattice.

Fruit splitting

Indication: This common ailment looks like gashes on your fruit and is caused by extreme temperatures or irregular watering.

Treatment: Water regularly and from the root.

Tomatoes produce fruit from now until the first frost. If you have to start anew, you still have time for the enjoyment of great fruit. Just be sure when selecting new plants that you look for nice green leaves and healthy fruit.

Check back later this summer for delicious ways to use your tomato fruit bounty!

Leah Blinstrub is a registered dietitian and health coach with Blue Cross Blue Shield of Michigan who enjoys cooking, being outdoors with her dog Oscar and spending time with her 1 year-old son and husband. She’s a big fan of a good tomato.

Photos by Ian Fuller and Jennuine Captures



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