3 Causes of white spots on tomato leaves

White spots on tomato leaves

On a regular day, the tomato has shiny green leaves that symbolize a healthy and happy plant. But, as many tomato gardeners know, that is not always the case. Tomato leaves often turn yellow to brown and purple. These are usually the first signs of a health problem and should be corrected immediately to protect your harvest.

1. Powdery mildew

Powdery mildew caused by a variety of fungi is a common disease of tomato plants. Avoiding this is not easy as it is often carried by insects such as air currents and aphids. Powdery mildew is most prevalent when the temperature is hot and dry or hot and humid for a long time. The fungus can also leave the winter in plant debris and manure, coming out when conditions are right. It forms a powdery white or gray dust in cracks on the surface of the leaves and stems. It usually starts at the base of the leaves, which can be difficult to catch when starting. Young leaves of plants are more likely to develop fungi, especially when the plants are pregnant and new rapid growth of leaves occurs. It also spreads to flower buds and fruits.

How to prevent powdery mildew on tomatoes

Place the tomato plants properly for good airflow. Aim at 18 - 24 inches for best results. Make sure the plants get enough sunlight. They should get at least 6-8 hours of full sunlight a day. Water the soil and prevent the leaves from getting wet. Wet leaves attract fungi and spread the disease. The drip irrigation system is suitable for growing tomatoes. It may be expensive, but if you want to grow tomatoes for a long time, it is worth the effort and cost.

2. Sun scalding

Tomato leaves form white spots on their leaves from sunlight. When the leaves are exposed to intense direct sunlight, they can be damaged and begin to turn white. This may be the result of transplanting soft seedlings into beds outside of a safe greenhouse where the plants are not used to intense sunlight or heat. Sun-dried leaves dry out and turn brown and fall off the plants. It inhibits the growth of the plant and compromises overall health. If the fruit has already formed, white blisters will appear on the skin in the sun.

How to prevent sunburn on tomatoes

7-10 days before planting, harden your tomatoes before planting in outdoor garden beds. Start in the shade outside and give the seedlings a little more sun each day. On the last day, leave the seedlings out at night until the temperature is above 50F. If your seedlings are happy the next day, transfer them to the garden. However, if they are depressed or withered, try the same process for a while before planting them in the garden. If your plants are already in the garden, cover them with a shade cloth to keep them out of the sun. As they grow, shorten the time under the shade cloth to harden them.

3. Late Blight

Large brown and white spots on the leaves can be caused by severe tomato fungus - late blight. It is caused by a fungus called Phytophthora infestans. This fungus is highly contagious and spreads rapidly, killing plants within a day or two. The only way to cure this disease is to destroy the plants. Do not add them to your fertilizer or it will spread in your garden.

Late blight usually appears in summer or autumn and is more common in wet weather. The light green spots on the tips of the leaves change from brown to black and a faint white mold can be seen at the base of the leaves when moist. Green fruits have brown spots and white fungus.

How to Prevent Late Blight on Tomatoes

Continued use of bio-fungicide or copper fungicide after rain, especially for fungal diseases like blight, can help prevent this disease. Applications should be made at least once a week.

Avoid planting tomatoes near potatoes. Both of these plants belong to the same nightshade family and enjoy the same soil type and nutrients. They also suffer from the same diseases. Planted with each other, they compete for nutrition and are vulnerable to unhealthy and delayed blight.

Because late blight is a highly destructive disease (Phytophthora in Latin means 'plant destroyer), it can cause late blight outbreaks across the country.