Preventing fungal diseases in tomato

For those living in areas with hot humid summers, getting a good tomato harvest can be a struggle. Many times tomato can become afflicted with fungal diseases like verticillium wilt, fusarium wilt or alternaria.

Alternaria, also known as early blight, causes “bullseye” leaf spots and can cause lesion on the fruit. Fusarium wilt causes the plant’s leaves to wilt and turn yellow and then brown. It usually begins on the lower leaves. Like fusarium wilt, verticillium wilt begins at the bottom of the plant causes yellow spots to form on the leaves before the leaves turn fully yellow or brown.

There are also many other tomato afflictions you could be experiencing in your garden; these are just a few common ones.

Don’t handle your tomato when they’re wet

Fungal diseases are passed through moisture. Avoid working with your tomato plants until after all the dew or rain has dried off.

Use drip irrigation

Using drip irrigation is more efficient and can help limit the spread of fungal diseases because the water is going directly to the plants’ roots. For those with small gardens, it is also possible to spot-water the base of the plant. If you must use overhead watering, water in the early morning so that the plant will have time to dry off during the day.

Rotate your crops

Many fungal diseases that afflict tomato live in the soil. To keep your tomato disease free, you must rotate your crops. Do not plant tomato or other nightshades (including potato, pepper and eggplant) in the same space multiple years in a row. You should use a minimum of a four years and rotate.

Keep your soil & plants healthy

Along with rotating your crops, you should also work hard to improve your soil’s health which will help you grow healthier, less vulnerable plants. Get your soil tested and add amendments as needed. Practice no-till agriculture. Use cover crops and good quality compost to add fertility and organic matter to your soil. Mulch pathways and around plants to add organic matter and habitat for beneficial fungi and microbes.

Plant disease-resistant varieties

Some varieties have been specifically bred to better tolerate these diseases.

Try a fungicide

If all else fail, you can find organic fungicides. Keep in mind that organic does not always mean completely harm-free. Many fungicides will kill off your soils’ good fungus, as well as the bad. Some fungicides like copper can even cause toxicity in your soil if used too frequently or in high quantities! Having tomato diseases ruin your harvest can take a lot of the fun out of gardening.