Gardening

How to control tomato blight?


A real plague, early blight of tomatoes covers the plant with spots and makes the fruits unfit for consumption. Prevention and natural remedies, find out how to fight this disease in the organic garden!

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What is early blight?

Early blight is a fungal disease, that is, caused by fungi. The culprits are: Alternaria solani (for tomato) and Alternaria alternata ! Like all fungi, they occur in a humid and hot atmosphere. While this disease mainly affects tomatoes, it can also affect potatoes, beets, fruit trees, cabbage, carrots and eggplants. These fungi stay in the soil and survive winter temperatures. They are carried by rain, wind, contact with between the soil and the plant or already infected seeds. In a humid and warm atmosphere, the spores germinate and quickly infect tomato plants.

What are the symptoms ?

Concentric black spots develop on leaves, stems and fruits. On the fruits, the spots cause rots, they become inedible. Don't confuse early blight with late blight! The latter develops yellow spots which eventually turn brown. Watch the weather, this disease appears in a hot spring. If it rains, it increases the risk, but sometimes the dew followed by a hot afternoon, is enough to create an atmosphere conducive to early blight.

Preventive control techniques

  • Grow your tomatoes under cover to avoid dew and precipitation.
  • Space the plants to avoid creating wet areas.
  • Do not wet the foliage when watering. Don't hesitate to use a water bottle cut in half and planted in the ground so as not to touch the plant.
  • Rotate crops.
  • Do not install plants susceptible to the disease side by side.
  • Choose seeds that are certified as healthy and do not take seeds from infected plants.
  • Choose hardy and disease resistant varieties.
  • Apply a layer of mulch so that the fruit does not come into contact with wet soil

Preventive natural treatments

Always in prevention, consider using liquid manure, infusions and decoctions which serve to strengthen plants, help them take root, boost growth and fruiting.

Horsetail manure

This natural antifungal is used as a spray. It is not used pure, it must be diluted to 10% (9L of water for 1L of liquid manure). We use it for Water the plants, once or twice a month.

You can make it yourself or buy it from a garden center.

Garlic infusion

Garlic has antibacterial and antifungal properties. It is commonly used to prevent the onset of fungal diseases, such as early blight. You can easily make a garlic infusion at home, by carrying a large pot.

  1. Finely chop 500g of garlic.
  2. Put these small pieces in 5L of water
  3. Bring to a boil, then simmer for 30 minutes
  4. Turn off the heat and cover
  5. Leave for 12 hours
  6. Filter your preparation by pouring it into bottles and cans
  7. That's it ! It is ready to use with a sprayer.

Bacillus subtilis

We use this bacteria to occupy the space and thus prevent fungi Alternaria to settle down. By secreting molecules, it also allows fight against spore germination.

Curative biological treatments

There is no cure for the fungus Alternaria solani, the one that touches the tomato. When it comes to potatoes, beets and citrus fruits, there is a treatment that can overcome theAlternaria alternata. This is another fungus (Aureobasidium pullulans), which is introduced to compete with Alternaria. For the tomato, all that remains is to remove the affected plants and take care to apply all preventive measures.

Video: How to Defeat Tomato Blight (October 2020).