Brown Rot Tomatoes: Causes + Solutions (with Pictures)

the essentials in brief

• Late blight is caused by the fungus Phytophthora infestans.
• Simple home remedies can help with an acute infestation, but mainly support preventive measures.
• Proper care (especially watering) protects against infection.
• Infested parts of the plant should not be placed in the compost. A rotation of crops is recommended.

What helps against late blight in tomatoes?

All plant parts of the tomato should checked regularly for brown spots will. Early detection of acute late blight enables countermeasures to be taken. And if you had to deal with late blight in the previous year, we recommend preventive methods such as spraying with home remedies and protection from the weather.

home remedies

Before the chemical club is fetched from the basement, the use of sustainable home remedies is recommended. The tomato itself, the bed and last but not least the human being benefit from an ecological treatment. Therefore, chemical sprays should always be used after no less effective home remedies.

Acute treatment with home remedies

Field horsetail broth. The should be preventive South be sprayed on the leaves at regular intervals from spring to summer. If a slight infestation is noticeable, all parts of the plant are injected three days in a row. Alternatively, a ready-made horsetail brew can be used. The Brandling concentrate is available in a 3 L canister for approx. Available for 25 euros.

Sage tea with baking powder. If the infestation is already far advanced, sage tea with baking soda can still stop the fungus. To do this, sage is boiled with hot water like tea and steeped for approx. left to infuse for 10 min. After cooling, two teaspoons of baking powder are added to the infusion. Stir everything well, pour into a spray bottle and hose off the plant until dripping wet.

Preventive measures with home remedies

Spraying with skimmed milk. Mix 100 ml skimmed milk with one liter of water. When mixed well, the solution can be generously sprayed onto the plant. The microorganisms in the milk create an inhospitable surface for all kinds of fungi without harming the tomato itself.

Spray with baking soda. Probably the most cost-effective method of protecting tomato plants from fungal infestation in the long term. For the correct mixing ratio, 8 g of baking soda are dissolved in 1 L of water. The liquid can then be sprayed onto the leaves with a spray bottle.

spray

If the worst-case scenario occurs - late blight affects the entire bed or greenhouse - chemical sprays are usually the last resort. The worst can be prevented with COMPO mushroom-free. For about. For 15 euros you get 20 ml of the highly effective fungicide, which when diluted results in 33 liters of spray water.

damage picture

First, an infestation manifests itself in the lower leaves that get brown spots and wither over time. The same thing happens to them fruits - you receive brown spotswhether ripe or immature. The fungus also damages the Stem on which brown-black areas form. Humid weather greatly favors infection and spread.

fruit

Yellow, green or red tomatoes show the same damage pattern. They usually get light brown or yellowish spots on the upper half. While hard in the early stages, the discolored areas gradually soften until they are mushy and rotten.

leaves

The leaves turn brown-black from the tip. Spots form that are blurred and appear moist. Over time, the entire leaf will wilt until it eventually falls off. The underside of the leaf reveals a whitish coating, similar to that of the mildew. From this point on, the entire plant is usually affected.

How can late blight be recognized in its early stages?

The initial stage of late blight and brown blight can usually be on the lower foliage watch. The leaves form grey-brown spots that are not clearly defined. Over time, a white down forms on the underside of the leaf; the stalk turns black in places, and eventually the tomato fruits rot.

Fungal infections are usually caused by infected potato tubers. For this reason, tomatoes and potatoes should not be in crop rotation are planted and are not directly adjacent to the bed.

Are the fruits affected with late blight still edible?

Even if the tomato on a plant suffering from late blight looks edible, it may already be infected. To be on the safe side, you can harvest the fruit and leave it there for a while, separated from others. If the tomato is unblemished, you can eat it.

How can late blight be prevented?

Aside from sustainable budgetary funds splashed on the foliage and fruit, the Location, the variety and, last but not least, care are crucial to avoid late blight infection. A happy plant is a healthy plant!

site selection

Potatoes should be planted as far away from other nightshade plants as possible (this includes the tomato). Because the egg fungus Phytophthora infestans "hibernates" in the roots of the potatoes. This dissolves in the ground and is transported to nearby plants via spray water and wind. The further away the tomato and potato are from each other, the lower the chance of infection.

planting distance

In addition, tomato plants with aDistance planted about 70-80 cm apart. On the one hand, this gives the tomatoes more space to grow, so that infected leaves do not touch each other. On the other hand, the distance between the shrubs improves the evaporation of water.

Sunny place

Everyone knows that tomatoes love the sun. But a sunny spot not only ensures sweet, ripe fruit, but also promotes the evaporation of water. The fruits need at least six hours of sun for healthy growth and dry leaves. Incidentally, the sensitive plants do not like rain or watering from above.

Resistant tomato varieties

Although growers around the world are doing their best: there is no tomato variety that is resistant to late blight. However, there are among the wild tomatoes naturally hardy varieties. Of the grafted ones, there are also one or the other variety that, on average, can deal better with fungal diseases.

wild tomatoes

The fruits of the Humboldt tomato (Solanum humboldtii) do not end up in the world, but with great certainty in salads. They grow about the size of cherry tomatoes and have a unique berry flavor. Those who like it even more "original" should consider the currant tomato. It is much smaller and tastes mildly sweet. Both varieties have in common their high resistance to late blight.

Processed tomatoes

The selection of cultivated tomatoes is significantly larger (and more colourful). The Primabella variety delivers a good mix of popularity and resistance. The robust cocktail tomato tastes tangy and sour and is therefore often grown for pure snacking. A lot of flesh and colorful sub-varieties make the De Berao tomatoes the favorite of sauce specialists. The cut-resistant Phantasia F1 is ideal for salads and Italian cuisine.

Care

The preventive Care essentially comprises three aspects: rain protection, correct watering and squeezing out. So that you don't have to constantly stand by your tomatoes with an umbrella, either a location under the roof or the construction of a rain roof is recommended. When watering and squeezing out, however, you cannot avoid daily attention.

rain protection

Fungi need moisture to spread and grow. Therefore, the benefit of rain protection is self-explanatory: keep the tomato foliage as dry and fungus-free as possible. To do this, you either look for a covered (but still sunny!) place for the tomato right away before planting it, or you build a small roof in the bed.

Proper casting

With the Pour from below everything is literally not in order. Because a hard jet of water on the soft soil can quickly create splashes that land on the lower parts of the plant. There are many pathogens in the soil, which - well moistened - find their way onto the tomato.

Pot with a hole in the bottom. A clay pot with a hole in the bottom is placed in close proximity to the root of the tomato plant and buried to the brim. The irrigation water is therefore only poured into the pot, which releases the moisture evenly to the ground.

casting ring. The plastic rings, which cost around 10-20 euros, work on the same principle as the simple pot with a hole. However, when planted in the ground, the stalk is also surrounded by its personal moat, which keeps pests such as snails away.

Olla. An olla is similar to the clay pot with a hole in the bottom, but is a closed vessel. The water is continuously released into the soil as the soil becomes dry. The advantage of the Olla is its capacity. With up to 6 L, you can keep 1 m² of bed area moist even over dry periods and take care of several plants.

Pinch out and defoliate

A distinction is made between two types of shoots in the tomato: the fruit-bearing and the miserly. The latter form exclusively in the axils between the trunk and the former growth shoots. They are stingy because they do not produce fruit, only leaves. That's why they should miserliness be removed, which promotes ventilation.

Same location the following year despite brown rot?

The old location has several disadvantages. The risk of infection is generally high there, since one plant has already been infected. There may be a potato plant in the neighboring garden that infected your own tomato with the wind (and through the fence). In addition, the soil at the old site is contaminated by the infection.

Brown rot in the greenhouse: to replace soil or not?

The soil in the greenhouse does not have to be changed despite an infestation. But it is important to do well mulching and incorporate fresh substrate into the soil. Rods and cords that served as climbing aids must be cleaned with hot water or destroyed.

Brown rot in the bed: Same location in the following year?

As a precaution, it is good to choose a different location. Due to the usually limited space in the garden, however, new substrate can be worked in and the soil through - as in the greenhouse mulching and Fertilize be worked up. This introduces new nutrients into the soil.

Stem rot, fruits brown - Similar diseases

Not all brown spots on the fruit and leaves have to be caused by late blight. There are other diseases that have similar symptoms. These include stem rot and blossom end rot.

stem rot

Stem rot can be recognized by the brown spots on the stem of the tomato plant. The fungus Didymella lycopersici is the trigger. Unlike late blight and late blight, the stem becomes blotchy and discolored first. Black, concave imprints form in the bark. But the leaves and fruits also become rotten.

Causes. The fungus enters the plant via spray water through injuries or respiratory openings. There the pathogen first spreads via the meridians, which then show the corresponding symptoms of the disease.

symptoms. Black, concave areas on the stem are the first to be seen. Then the fungus spreads to the leaves, which have circular brown spots that are progressively fading. Dark dots appear inside the circles. Starting at the base of the stalk, the fruits become rotten.

Prevention. Resistant varieties that come from healthy seed are less likely to suffer from stem rot. In addition, great importance should be attached to hygiene in the bed. When pinching out, be careful not to cause any major damage to the bark, as this acts as an entry point for pathogens.

blossom end rot

Blossom end rot is not a classic disease, but a sign of a nutrient imbalance. The tomato fruits become rotten around the bud base. There is a lack of calcium, which is responsible for stable cell walls. As a result, the skin of the fruit becomes softer and softer until it eventually collapses. The underlying tissue becomes soft and putrid and then hardens.

Causes. If blossom end rot occurs, there is a lack of the important plant nutrient calcium. There may be too little calcium in the soil. However, the use of too much nitrogen fertilizer is often the cause. As a result, the tomato plant grows so quickly that it can no longer supply other minerals.

symptoms. Small black dots can suddenly be seen on the former blossom base of the tomato fruit. After a short time, the skin turns brown, soft and sinks in. Then the fabric becomes hard and leathery to the touch.

Prevention. If the plant exhibits excessive growth, nitrogen fertilization should be discontinued for a week or two. If this is not the case or if the symptoms do not improve, the tomato can bedrock meal be supplied.

FAQ

Can tomato plants with brown rot be composted?

No, tomato plants with late blight and late blight should not be put on the compost as the spores survive for a long time.

Does copper wire help with late blight?

No, scientifically, the use of copper wire could not help preventively or acutely with late blight.

What helps against late blight?

Good prevention helps the most. In addition to treatment with home remedies, this primarily includes appropriate care.

How does late blight develop?

Late blight is caused by a fungus called Phytophthora infestans. The pathogen reaches the tomato plant by touch, wind or spray water.