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Late Blight Tomato and Potato, Symptom and Prevention

Late blight is one of the major concerns growing potato and tomato. Potato and tomato are two major vegetables being damaged bitterly by the late blight. Late blight occurs when the fog is dense for a long and the sunshine is not seen. Due to excessive temperature loss, the harvest in the firm is damaged seriously especially the tomato and potato as the plants are sensitive, soft and cannot tolerate critical period.

potato blight, tomato blight

Sometimes it happens that late blight cannot be controlled applying the remedies. It is because the temperature. If the attack is mightier than the dose of the remedy, it is not possible to manage them and situation goes out of our control. So, we must have a close communication with an agriculture officer. Again, misuse of wrong medicine can breed maximum damage. You can also see green been diseases, symptom and prevention.

This video credit by – NYSIPM

Causes and Symptoms

Late blight occurs from a kind of fungus. At the primary stage, the leaves, top of the plant and the branches are marked with several curved water mark. Gradually the mark turns into black and brown. Soon after the marks get bigger shapes and grab a noticeable area of the leaves and branches. Affected area is circled by a fade green and brown ring mark. White powder of the germs is seen at the bottom and opposite of the leaves.

These germs blow with the air, fall over the healthy plant, start influencing them also. If the moisture in air is 90-100%, approximately all the plants will be affected and will be destroyed within 2-3 days. In cause of potato, the leaves along with the plants are burnt. For tomato, the plants are marked with dark spots initially, the plants start too rotten ultimately.


Temperature 10-200 c and moisture in air 90-100% is best suited for the late blight. After the disease starts attacking, it increases affecting in 21-240 c.

Expansion of the Disease

Affected seeds of potato and tomato are mainly responsible for such kinds of crisis. The germs are transferred by the air and water and sometimes attack the healthy plant directly one after another.

Steps to Control

  • To control the problem, we must take some immediate measures and they are as below
  • Do not collect seeds from the affected plant
  • Use refined seeds for sowing
  • Always keep the firm clean and weeds free
  • Be careful collecting the vegetable so that the affected one may not be mixed with healthy one
  • Collect the affected trees and burnt them all or ground them deeply.
  • Collect the potato when the trees get dry. So the germ will die out.
  • Protect the bottom of the plant providing extra soil to make the bottom up from the level
  • Never collect the harvest if there is downpour.
  • Farm them in advanced to avoid such crisis.
  • Apply irrigation to reduce the activity of the germs.
  • Apply the required fertilizer only.
  • Have a consultation with an agriculture officer immediately if the situation seems to be out of control.

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