Early Blight Control: How to Identify and Get Rid of Early Blights

One of the most common diseases in tomatoes and potatoes, early blight happens almost every growing season. It affects almost every part of its host and the outcomes can be devastating, especially for commercial growers. With this, to minimize crop damage, it is important to be familiar on how to treat this condition to guarantee that your plants will not suffer from severe infestation.

What is Early Blight? 

This disease is caused by Alternaria solani fungus. The latter is a part of a diverse family of pathogenic fungi that have a reputation of causing serious diseases in a wide array of plants. It lives and overwinters in a debris with infection. It can even survive in the soil for several years. If the climate is mild, it can easily get through one season to another. Plants that are weak and with existing health conditions are more vulnerable.

When it comes to external conditions, the pathogens favor environments with warm and humid climate. If there is heavy dew of rain, there is a higher likelihood that early blight will be a problem in the garden. Humidity of 90% or greater will favor the pathogen carrying the disease. The transmission of the spores can occur through different methods, such as with wind and human contact. Using equipment with spores is one of the most common ways of transferring it to another plant.

Another important thing to note about this disease is that it is more common in older tissues than in young ones. The duration of the initial infection to the manifestation of symptoms can vary, but this will depend on age, susceptibility, and environmental conditions, among other things.

Early Blight

Early Blight is Common in Old Tissues

Identifying Early Blight’s Damage 

Host Plants 

Tomatoes and potatoes are the most common hosts for early blight. However, they can also attack other solanaceous plants, which include black nightshade, eggplant, and pepper. Brassica crops can also be hosts of the disease. 


Clueless if your plants are already suffering from early blight? The following are some of the signs that you should watch out for:

  • The lower and older leaves of the plant will show brown lesions. These may start out small, but upon maturity, they will grow bigger. On average, the diameter will be one to two millimeters. They will form dark rings on the leaves and as the disease progresses it will turn brown from yellow.
  • The lesions may appear not only on the leaves, but also stems. They will make the stem dry and sunken. There will be dark brown concentric rings and will make the plant unattractive.
  • For the fruits, there can be lesions near the stem, especially for tomato. Black spores may also surround the lesions. Leather and black ridges may appear, which will cause the fruit to fall off. In potato tubers, meanwhile, there will be dark lesions with purple borders. 

Results of Infestation 

The infestation resulting from early blight will vary depending on the host plant, its health condition, age, and external environment, among other factors. Cosmetic damage will be common, specifically in the form of discoloration and defoliation. When there are no more leaves in the plant or when the leaves are already weak, this also inhibits the flow of nutrients, and hence, can make it wilt and die. In some cases, the fruits and crops will end up being unmarketable. This makes it cause economic losses on the part of the growers.

Early Blight Plant

Tomatoes and Potatoes are the Most Common Hosts for Early Blight

How to Get Rid of Early Blights

Natural and Organic Solutions 

For non-toxic but effective ways to deal with early blight, the following are some of the promising solutions:

  • Be careful in the selection of the plants to grow. See to it that the seeds are free from pathogens. It will also be better to choose varieties that are resistant to the disease. Some of the varieties that can resist the disease include Mountain Magic, Mountain Supreme, Iron Lady, Juliet, Supersonic, Jetstar, and Early Cascade, among others.
  • You also need to pay attention to the external environment. For instance, keep the plants free from hairy or black nightshade both of which can attract pathogens that can bring early blight.
  • Fertilizing will also help, especially in keeping the plant in its peak condition. However, limit the use of fertilizer. Over-fertilizing can also encourage early blight.
  • When pruning or harvesting, see to it that you will use clean equipment. Shears and scissors are some of the most common modes of transmission, which makes it important to make sure that they do not carry pathogens with them.
  • Humidity is one of the factors that encourage the presence of pathogens causing early blight. With this, it will help to reduce humidity through using organic or plastic mulch. This will also be effective in providing a protective barrier between leaves with infection and the soil.
  • Two-year crop rotation is also an excellent solution. Do not plant other susceptible crops in the same spot where you have previously grown plants with early blight.
  • Before planting, see to it that the garden is clean. Tilling the soil and removing decaying vegetation will help to prevent infection.
  • Pull out any plant that you suspect is already suffering from an infection. Letting it remain on the ground will make other plants susceptible to the disease as well. Throw the plant away and do not use it as an organic compost as this will only contribute to the spread of the disease. 

Chemical Solutions 

A lot of people tend to stay away from chemical controls because of the possibility that they are toxic. Yes, they have harsh active ingredients, but they are still effective in the prevention of early blight. The important thing is to ensure its proper application to yield the best outcomes.

Fungicides are on the top of the list for chemicals that will control early blight. Repeat the applications based on the instructions from the manufacturer. Some of the most common active ingredients and trade names include penthiopyrad (Fontelis), boscalid (Lance), pyrimethanil (Scala), and mancozeb (Dithane).

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