Homegrown tomatoes: How to prevent pests and diseases

What's the best way to control pests and diseases? Grow healthy tomato plants!

Just like humans, the weak, frail and stressed catch illnesses. To grow a healthy tomato plant, remember we need:

  • Enough sunshine
  • Good soil
  • Right amount of water
  • Fertilizer
  • To pick a good variety to grow
  • To pick the best times of year to plant
  • Sulfur dust

Young plants are normally very healthy. As they grow, and tomatoes set on, disease goes after the plants. We try for a great crop of tomatoes before disease gets them. Usually we are successful.

Probably the most common tomato problem is dealing with fungus. 80-90% of people get fungus of some sort on the leaves and just think it’s a normal part of the plant’s life cycle. Or that their tomato maybe needs more water or fertilizer. And there are hundreds of different kinds of fungus that you can eventually see on the leaves. Leaves dry up, turn brown, yellow, spotted, die and fall off. Most of this is some form of powdery mildew. There are hundreds of different kinds of powdery mildew.

Once this fungus is on the leaves, it reproduces and spreads. The fungus reproduce by spores which are tiny microscopic bodies floating around in the air that eventually land on your tomato plants and spread. The spores are spread by wind, water, etc., to new leaves or other plants. Once on your plant you will see leaves die. Leaves of the tomato plant are food factories for the tomato plants and if you have less food and energy, you will have less tomatoes and stressed plants.

Look at the plants above. See the fungus? The 3 plants on the right have been treated with a light coating of sulfur dust on their leaves. The plant on the far left was never treated with sulfur dust. Notice down low on the 3 that have been treated: signs of fungus. These discolored leaves are signs of fungus, time for a light coating of sulfur dust.

Use sulfur dust to stop the spread of the fungus. Sulfur dust prevents the fungus from reproducing. Sulfur dust works and it is organic; it comes from Mother Nature. Once a tomato plant has reached the goal of reproducing fruit and seeds, the tomato plant naturally reduces the fight against pests and disease. Once a tomato plant has reached its peak and is near end of producing, I generally stop caring about pests and diseases and just get ready to pull it out and put a new one in.

Always remember, a tomato plant’s goal in life is to reproduce and then it will eventually die.

I do not use pesticides. Tomato plant disease and pests are everywhere … in the soil, in the air, maybe on your hands, maybe on your tools. If a runny nose is going around, the tomato plant will probably get it.

When possible buy disease resistant tomato plants. The label on the plant will indicate if that particular variety is disease resistant. Remember, the word is resistant to a disease not immune from a disease.

You are welcome to share this information with others—family, friends and clubs, etc.

Sharing tips helps us be better growers.

Dave Freed / 🍅 the Tomato Guy

🍅 Bumper Harvests Made Simple - Discover the secrets to cultivating tomato plants that yield over 100 lbs of fruit!

🔍 Expert Advice At Your Fingertips - Get straight-to-the-point guidance on tomato care, including:

  • Pest Control: Keep your tomatoes safe from critters.
  • Disease Prevention: Spot signs early and take action.
  • Optimal Growth Tips: Watering, sunlight, soil, and more!