Like powdery mildew, downy mildew is a fungal disease (linked to pathogenic fungi that are quite devastating), the propagation of which in the vegetable garden can cause great damage. Between rot and necrosis, part of the harvest can quickly be lost. Indeed, when this fungus takes hold, we often have no other choice but to remove and burn the affected parts of the plants. And yet a few good prevention and treatment actions can make all the difference. It is therefore crucial for any gardener to know and know how to recognize tomato downy mildew. Grandmother gives you here all the secrets to eradicate one of the most dreaded fungal diseases in the garden without chemical phytosanitary products!
Everything about tomato mildew: know it… and recognize it!
The term downy mildew actually includes several fungal diseases. In the case of the tomato, it is the fungus Phytophthora infestans who is involved. It is favored by a hot and humid weather (with a humidity level greater than 90%). With summer looming, and thunderstorms and precipitation that multiply during this very hot period, the spores may develop even more easily in the vegetation of the garden. We then perceive certain first distinctive symptoms of the disease which are amplified as it sets in. For example, more and more black spots and brown spots settle on the front of affected leaves or on fruit. On the back of the leaves, however, there is a fairly powdery white layer. At the slightest of these signs, we must act quickly!
How to prevent the appearance of late blight in tomatoes?
Choose a variety more resistant to disease
No variety will be 100% resistant to downy mildew. However, some are more sensitive to it than others. Opting for a more resistant tomato will allow it to continue to produce viable fruit despite the contamination. This includes cultivars such as Crimson Crush F1, Fantasio, Iron Lady F1 organic, Maestria or Philovita F1 (for cherry tomato lovers).
Caring for the tomato plantation
First of all, it is necessary space the tomato stems. This trick, well known to gardeners, allows the plants to breathe and limits the phenomenon of maceration. Planting in full sun, but also avoiding watering the leaves will also limit disease. In addition, in the management of the vegetable garden, we will avoid planting tomatoes next to potatoes. The latter indeed quickly tend to catch the disease and infect their neighbors!
Use natural products with preventive action
Spraying certain preventative treatments can help strengthen tomato plants. When applied at the onset of spring, they will make your plants more resistant to disease! Here you can rely on the decoction of horsetail or nettle manure like comfrey.
What to do when the tomato is contaminated with late blight?
In the event of an infestation, action should be taken as quickly as possible before the plants are completely destroyed. But what can be used to treat tomato plants? Very often, we talk about Bordeaux mixture. However, although authorized in organic farming to treat downy mildew of grapes, tomatoes or potatoes as well as scab, this product remains controversial. Fortunately, there are other solutions gentler on the environment and copper-free that could accumulate in the soil!
Baking soda to treat disease
Baking soda helpsimprove pH at plant level. Made less acidic, it will hinder the development of the fungus, thus helping to eradicate it. To do this, simply mix a teaspoon of baking soda and a teaspoon of liquid black soap in a liter of water. Then, apply this product with a sprayer as soon as the tomato is planted, once a week.
Install the right flowers around the tomato to counter mildew
The right growing associations are a key element in permaculture. This allows as many hunt pests that of fight diseases. The preventive solution would, for example, be to install basil or nasturtium plants to limit the appearance and development of downy mildew. Chinese chives would be active against the fungus Phytophthora infestans.
Use a greenhouse
The greenhouse protects the tomato plants from the morning dew as well as from bad weather. This avoids exposing the foliage to moisture conducive to fungi. However, you must ensure that your greenhouse is well ventilated, as pests can quickly proliferate there. You will also no longer be able to rely on the rain to hydrate your substrate. Also, a regular watering as well as the choice of a rich and fresh soil. This solution will also give you a longer harvest and fruit that ripens faster.
Are late blight tomatoes edible?
All the prevention and the efforts that we put in our vegetable garden are not always enough to avoid disease. Also, when the mildew is indeed there, we may be tempted to eat the fruit anyway. Is it a good idea ? In fact, it depends on the condition of your tomatoes. Once infested, they tend to experience a rotting quickly and taking a very bad taste. You could also get sick. This is the reason why it is safer not to consume a fruit with lesions. However, when the infestation is just starting, it is possible to consume the intact fruit. Pick them as soon as possible and let them ripen at home.