Causes of premature wilting of potato tops

When the potato tops wither, the tubers, devoid of photosynthetic products, stop growing. It is normal if the stems dry up in due time, but in case of premature wilting of the shoots, you can not count on a rich harvest.

In hot weather, potato tops often droop due to lack of moisture. It is easy to make sure that the plants are suffering from drought: just try the soil with your hand on the garden bed at a depth of 8–10 cm from the surface. If the soil is dry, it means that the potato plantation needs to be watered.

Plants are especially in need of moisture during budding and flowering. To make potatoes easier to endure drought, organic or mineral fertilizers, a growth stimulator, are added to the water for irrigation. If the bushes are healthy, then during the day after watering, the stems straighten, and the leaves again become fresh and elastic.

Diseases that lead to premature wilting of the tops

If the soil is moderately moist, and potato bushes wither on the site, the reason is most likely in some kind of disease. It is very important to take preventive measures in time and prevent an epidemic.

There are 3 universal rules, compliance with which can significantly reduce the likelihood of an epidemic;

  • crop rotation is required;
  • you cannot plant tomatoes, eggplants, peppers, physalis and other nightshades next to a potato plantation;
  • the affected bushes should be dug up, the tops should be burned, and the place where they grew should be disinfected (depending on the causative agent, fungicide or antibiotic).

Pillar wilting

The potato pillar is considered the scourge of the southern regions, but it is found throughout the European part of Russia. In diseased stems, internodes are much shorter than in healthy ones, there are many axillary shoots. Young leaves grow small, curl around the central vein or fold in half, covered with red spots. The flowers sometimes turn green, the petals are deformed.

During droughts, when epidemics are most frequent, the tops begin to wilt 7–10 days after the defeat. In cool weather, the disease progresses more slowly, wilting occurs in 2-3 weeks.

Pillar wilting

The carriers of the stolbur are leafhoppers, therefore the plants most often become infected in late June – early July, when the mass flight of these insects begins. Stolbur symptoms appear in a month, in late July – early August.

The most important thing is to prevent the planting of tubers infected with stolbur: they give frail tops. Discard all filamentous potatoes during germination.

To prevent an epidemic, it is necessary to destroy leafhoppers. To do this, potatoes of mid-season and late varieties when planting are treated with a Prestige dressing agent or during the growing season they are sprayed with any insecticide against the Colorado potato beetle. For early varieties, insecticides are used with a short waiting period (Fitoverm, Bankol).

An antibiotic is used to disinfect the place where the diseased bush grew. Phytoplasmas can be destroyed with Tetracycline solution.

Fusarium wilt

Fusarium potato is caused by the fungus Fusarium oxysporum. Infection occurs through the soil, during transport or in storage. The likelihood of infection is especially high in hot weather with high humidity (80–90%).

Usually the disease manifests itself during flowering. The fungus destroys the vessels of the tops. Young leaves of an infected plant brighten, fold in half or twist into a tube (around the central vein). After a few days, all the leaves wither, and the stems droop, they can be pulled out of the ground without effort, since the root zone rots. On the cut of the shoot, orange-brown vessels are clearly visible: this color is given to them by the fungus. At high humidity, the shoots outside are covered with an orange bloom – fungal spores.

photo of fusarium wilt of potatoesFusarium wilt

To prevent plant disease with fusarium, the tubers are treated with Maxim, Fitosporin-M or another fungicide during planting. When an epidemic is threatened, the plantation is sprayed with a fungicide (for example, “Fitosporin-M” or “Alirin-B”).

Vertical wilting

The causative agent of verticellosis is the fungus Verticillium albo-atrum Reinke et Berthold. Unlike fusarium, verticellosis first appears on the lower leaves (mainly during flowering), and then reaches the upper ones.

The leaves turn yellow at the edges, become covered with brown specks, depressed brown dots and strokes form on the stems. The fungus clogs the vessels of the plant, which stops the flow of water to the leaves and tops of the shoots.

Causes of premature wilting of potato topsVertical wilting

Even if the tubers dug out from under a diseased bush look healthy, they do not survive until spring: the eyes rot. For the prevention of verticellosis, the plantation is sprayed with fungicides.

Bacterial wilting (brown bacteriosis)

The disease is caused by the bacterium Ralstonia solanacearum (Smith) Yabuuchi et al. (syn. Pseudomonas solanacearum Smith). The carriers of the pathogens are insects, but bacteria also spread through rainwater, dirty garden tools, and work clothes.

Infection occurs when a pathogen enters the wound of the tops or tuber. In the vessels of the plant, bacteria multiply very quickly and, sticking to each other, form blood clots. Because of this, the tops do not receive moisture and withers. Infected tubers rot in storage.

photo of bacterial wilt of potatoesBacterial wilting

Pathogens are especially active at high humidity and temperatures from +20 to +30 ° C. Potato plantations in the Far East suffer the most from brown bacteriosis.

To protect the potatoes, before planting, the tubers are pickled with “Maxim”, “Griffin” or a weak solution of copper, boron and manganese salts.

The stem nematode

If potatoes are constantly withering on the site, it is possible that the soil is infected with stem nematode. The presence of the parasite can only be established with the help of laboratory tests. The stem nematode is extremely tenacious and reproduces very quickly in a humid environment.

photo of potato nematode

You cannot completely get rid of the stem nematode. In order to control its number, potatoes should be planted in the same place no more often than once every 3-4 years. It is recommended to use rye as green manure.

Anna Evans

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