How to Get Rid of Powdery Mildew on Tomatoes

It feels great to pluck healthy tomatoes from your kitchen garden or farm for your home grocery or commercial venture. Tomatoes are the most popular vegetable fruits because you can consume them raw, cooked, or processed.

However, if you’ve ever grown tomatoes, you know tomatoes are prone to fungal infection, which may lead to poor or zero harvests.

Powdery mildew is among the blights that affect solanaceous vegetables and is caused by fungi, especially on large farms. The disease attacks foliage, stems, and occasionally fruits leading to minimal harvest.

When this fungal blight attacks the growing tomatoes, it thrives on nutrients and water from the plant foliage and stem, causing them to wither.

Caution: If not curbed early, the tomatoes die. In addition, this powdery blight interferes with food manufacture through photosynthesis, hence starving it.

Do you have growing tomatoes in your backyard or farm? Or do you plan to grow some soon? If yes, learn how to get rid of powdery mildew and enjoy a healthy harvest from this article.

How To Detect Powdery Mildew on Tomatoes

Prior to administering any fungicide for powdery mildew on your tomatoes, it is crucial to know how to detect it. The early signs of powdery mildew include the following:

1. A light gray powdery substance covers the leaves. As the infection spreads, the leaves appear to have been sprayed with ash.

2. A light shade of yellow spots on the leaf's surface turn brown as the infection advances.

3. The leaves shrink and grow less succulent.

When you spot the above signs, you should apply a remedy to curb further damage to the infected plant and minimize the spread to other plants. White powdery mildew starts on the foliage because the disease-causing fungi thrive on wet surfaces.

Furthermore, leaves are exposed to heat from the sun, and the high temperatures favor the spread of the fungi.

If not treated earlier, the infection spreads to the lower surface, stems, and fruits. An infected branch looks powdery and dry on the surface, while the fruits lack flavor.

These effects are caused by lack of water and nutrients for the plant caused by the parasitic nature of the fungi. Moreover, the powdery covering interferes with photosynthesis making the plant lack enough food.

How To Treat Powdery Mildew on Tomatoes?

Powdery mildew treatment involves curbing the spread of the disease-causing fungi from your garden. If you identify the infection early, you can use any fungicide containing copper and sulfur.

Sulfur is poisonous and therefore kills the disease-causing fungi, while copper denatures proteins and enzymes hence inhibiting further growth. Note that these fungicides are effective in the early stages of infestation.

Other effective powdery mildew fungicides include neem oil and sodium hydrogen carbonate. These organic remedies, however, are preventive rather than curative. Therefore, you should apply them before any visible signs of infection, especially during humid conditions.

Tip: The remedy you choose is determined by the current weather conditions and infection stage.

Here are four common ways of treating powdery mildew on plants.

1. Before infection: Mix 10ml sodium carbonate with 5ml liquid soap and dissolve the mixture in 20 liters of water. Stir the mixture to obtain a uniform solution. Using a knapsack sprayer, spray the solution sparingly on either surface of the foliage and stems.

2. During the early stages of infection: Add 5l of water to 2l of milk, stir the mixture to obtain a homogenous solution, and spray on the affected parts. Proteins in the milk act against those in fungi, killing them.

Furthermore, calcium ions found in milk boost the plant’s immune system. For this remedy to work effectively, temperatures should be high. Therefore you should apply it when the sun is shining.

3. To treat an existing infection: Organic remedies such as neem oil and powdery mildew fungicides effectively treat existing mildew on tomatoes. Here are some of them:

○ Cuprum and Sulphur- containing fungicides kill or denature the disease-causing fungi hence preventing it from spreading further. These are the best powdery mildew fungicide for infected tomatoes.

○ Potassium bicarbonate solution creates an alkaline medium on the infected parts. Fungi thrive in acidic media but become inert in basic or alkaline media.

○ Neem oil forms a cover on the disease-causing microorganism and prevents air entry leading to suffocation.

○ Uprooting mildew-infested plants help you curb further infestation in healthy plants.

How to Prevent Powdery Mildew In Tomatoes?

Ensuring your tomatoes stay free from powdery mildew infection is more economical than trying to get rid of the disease. Furthermore, healthy tomato stems produce more fruits than infected ones.

You can keep powdery mildew at bay right from land preparation to the harvesting stage in the following ways.

1. Plant your tomatoes in sections that receive direct sunlight to minimize dampness on the leaves. Powdery mildew grows faster in high moisture content, and keeping the foliage dry creates an unfavorable environment.

2. When planting, space your tomatoes well to expose them to sufficient air and sunlight. This keeps the leaves free of moisture.

3. Lower the nitrogen accumulation in the yard by applying fertilizers evenly and at intervals. The mildew-causing fungus grows in nitrogen.

4. Spray your plants with powdery mildew preventive remedies like milk and sodium hydrogen carbonate. This keeps fungus away and improves your plants’ immunity.

5. Add liming agents to your soil to raise its pH and make it inhabitable for powdery mildew. Quicklime is a good example of liming agents.

6. During the dry season, irrigate your garden by drip irrigation or manually. This ensures the roots absorb water while the rest of the stem and foliage is dry. Also, avoid sprinklers because they leave your tomatoes’ foliage wet.

7. As your tomatoes grow, prune them to enhance air circulation and exposure to sunlight. This creates a less humid environment on your farm.

Parting Shot

Learning how to keep powdery mildew in tomatoes at bay is crucial before you venture into tomato growing. Your yield depends on how healthy you keep the tomatoes. Nonetheless, it is better to prevent this fungal infection than to treat it.

The best method of treatment is organic fungicides and milk because they are beneficial to your plants.