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Tomato is one of the most common crops in any garden, especially urban ones. The tomato plant is a plant whose care is available to everyone, and its fruits can be enjoyed in so many recipes and in so many ways that it is difficult to resist planting a few to benefit from their harvest.

However, it is also a plant that tends to be attacked by some pests and diseases, since it is so widespread today. Therefore, it is important to know well what your enemies are in order to fight them properly. If you want to learn more about tomato diseases and see photos, keep reading us in this Green Ecologist article.

Tomato pests

There are various tomato pests that affect the entire plant, from the stem and leaves to the fruits themselves. Here we explain the most common:

  • One of the main pests that attacks tomato is Red spider. These small reddish or yellowish arachnids, as their name suggests, are very small and attack the plant by sucking its cellular juices to feed. The result is that the affected areas of the plant turn yellowish and end up necrotizing. When there are many, they form easily identifiable cobwebs, which they use to travel between plants.
  • The White fly, for its part, it lays its eggs on the underside of the young leaves of the plant, so that later the larvae feed on them.
  • Attack of the aphids in tomato plants, which appears in spring and autumn and is very typical in a great variety of plants.
  • We can also find the trips, which lay their eggs in the fruits, leaves and flowers.
  • The leaf miners, which make the laying inside the young leaves, from where the larva burrows feeding.

Tomato diseases

Between the tomato diseases that are more common we find the following:

  • Powdery mildew It is a problem caused by fungi that cause yellow and brown spots to appear on the leaves, causing them to wrinkle and dry out.
  • Gray rot It is caused by a fungus that causes brownish or grayish spots to appear on the leaves, stems and flowers, which also causes a moist and soft rot in the fruits.
  • Anthracnose it appears during the ripening of the fruits, in the form of spots with the appearance of rottenness, which increase in size with time, rendering the tomatoes useless for consumption. Learn more about this tomato disease in this other Green Ecologist article on Anthracnose: what it is and treatment.
  • Mildew Tomato is another fungus that affects the tomato plant in all its stages of development and causes wet-looking spots to appear on all its leaves and stems.
  • Alternariosis It causes circular spots with concentric rings, which end up causing affected areas of dark and elongated color and darkened and sunken areas in the fruits.

How to prevent tomato diseases ecologically

Finally, we offer several tips for treating and preventing tomato pests and diseases:

Tomato mildew

To avoid the attack of this fungus, it is necessary for the tomato crop to have good ventilation, with the plants far enough apart. This is especially important in the case of greenhouses, where ventilation is less and the fungus can appear more often. We must ensure that there is never stagnant water on the leaves of the plant.


To prevent the appearance of alternariosis you must avoid that the environmental humidity in the harvest remains too high, in addition to keeping the crop clean. If symptoms of affected plants or fruits appear, remove them immediately.

Powdery mildew

As with pests, with powdery mildew the most important thing is good crop hygiene, without organic matter that decomposes or attracts pathogens. It is also important to remove all weeds. Here you can see How to combat powdery mildew with home remedies.


If your tomatoes are attacked by aphids, garlic infusions sprinkled on the plant are a very good way to fight the plague in an ecological way. If you want to prevent their appearance, it is important to make sure to clean the garden of weeds and debris of other cultivated plants, and to keep humidity levels low.

In this other Green Ecologist article we give you the best home remedies to eliminate aphids from plants.

Red spider

The measures to prevent the appearance of the spider mite are the same as with aphids. Keep in mind that these appear when the temperatures are very high, so be especially careful in the warmer months. Also, avoid fertilizers with too much nitrogen content.

White fly

Once again, the important thing is to maintain the strictest possible hygiene in our garden, removing any remaining organic matter from both the tomato and any other plant. In addition, it is advisable not to fertilize at the end of the cycle, to avoid that the adult specimens are attracted to the young shoots.

In addition, we recommend reading these other gardening guides from Ecologista Verde

  • Homemade fungicides for tomatoes.
  • How to fight pests ecologically.
  • How to grow organic tomatoes.

If you want to read more articles similar to Tomato diseases, we recommend that you enter our category of Cultivation and care of plants.

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