BLUE SPRINGS, Mo. - Wet conditions make tomato plants susceptible to devastating diseases such as early blight and Septoria leaf spot. Now is the time to combat them in the vegetable garden, said a University of Missouri Extension horticulture specialist.

Typically, these diseases are controlled with fungicides applied at seven- to 10-day intervals, said Marlin Bates. But gardeners also can take other measures to prevent or at least delay the onset of these diseases.

"Everything we can do to reduce periods of leaf wetness will aid in fending off their development," Bates said.

Improving air circulation between plants helps dry leaves. Properly spacing the plants in the garden helps maximize air circulation without sacrificing valuable garden space. Bates recommends spacing tomato plants 2 to 3 feet apart.

Pruning is another effective way to ensure proper air movement around the plant. Removing shoots from the base of the plant so there are only two or three main shoots will open up the canopy and allow for proper air circulation. "These suckers should be removed before they get too long-usually when they are around 3 inches long," Bates said. Staking or caging each plant also opens up the canopy, allowing leaves to dry faster.

When watering the garden, he added, try not to wet the leaves. "Also, by removing infected plants from the garden, you can reduce the threat of disease for next year's crop."

Keeping your plants healthy will make them less vulnerable to disease, Bates said. Be sure plants have enough water, nutrients and sunlight. "To ward off diseases, start each season with proper garden preparation," he said. "Soil tests indicate appropriate pH adjustments, let you know if you have adequate organic matter content, and provide fertilizer recommendations." Soil tests are available at your local MU Extension office.

As added insurance, many growers apply fungicides during wet periods, when the threat of disease is particularly high.

An MU Extension guide, "Common Diseases in the Home Garden" (G6203), is available online at https://extension.missouri.edu/g6203 .