Potato pests and diseases

We have our potato crop and we fertilize it correctly . But over time there is a problem, and it is the appearance of potato pests or diseases . The indicated thing is to know what type of problem is presented to us in order to carry out an effective treatment. Let’s see how to treat them.



Wire worm  (Agriotes lineatus): this pest is also known as  brawn , they are worms that dig galleries on the tubers or roots of the potato. A high density of these worms lowers production performance significantly. On the leaves appears a chlorosis and a stopped or scarce growth.

Scorpion onion  (Gryllotalpa gryllotalpa):  this pest affects mainly the roots of potatoes. The product is damaged by the appearance of tunnels in the tubers, increasing the chances of the appearance of diseases, which we will comment on later. The onion scorpion is scary in size (<5 cm), but it spends most of its time buried, in addition to hibernating in the cold months.

Scorpion onion
Source: flickrhivemind

Snails  (Helix spp.):  Have nocturnal habits, so we will rarely find them in action. We can track them by following the shiny slime they leave behind on their movement. The snails that affect the potato crop are brown in color and are activated by high humidity or rain.

If the appearance of snails in the potato crop can be harmful to production, the following treatment can be followed:

4% methiocarb (3-4 kg / ha).

Potato caterpillar  (Laphygma exigua):  The potato caterpillar is green in color, with transverse white lines that form rings. They feed on the potato leaves causing holes and bites on them. In addition they can also attack the root so it can destroy the plant completely.

A treatment against the potato caterpillar consists of the application of insecticide:

10% w / v deltamethrin (0.075-0.125 L / ha)

Potato  beetle (Leptinotarsa ​​decemlineata):  this beetle can be found on the underside of the potato leaf. The larvae grow rapidly and are very voracious, destroying crop leaves and reducing tuber production by up to 70%.

Green  aphid (Myzus persicae): this aphid absorbs the cellular fluid by wrinkling the leaf and deforming it, especially the young leaves. The molasses they secrete attracts ants and diseases such as bold. The whole genus of green aphids (which attacks fruit trees such as peach, cherry, etc.) is susceptible to attack the potato crop.

 Potato moth (Phthorimaea operculella):  this lepidopteran causes galleries on the potato leaves, being able to burrow in the stems as well. The appearance of these galleries reduces production performance significantly.

Even with the potato harvested, the attacks also continue on the tuber, with excavations on it.


Alternaria (Alternaria solani):  this fungus attacks the entire plant, with the first symptoms appearing on old leaves. Small, circular spots appear on them, which become darker as the disease progresses. Later, defoliation of the plant occurs and yield is affected. The fungus develops favorably with warm temperatures and watering humidity.

 Anthracnose  (Colletotrichum spp.) : Another fungus that adds to the list of potato diseases. This fungus mainly attacks the leaves and fruits. On these there are some brown spots that darken with time. In addition, circular spots appear on the stems, with a watery appearance that blacken with time. The fungus can be dormant in unfavorable weather conditions, and become active when conditions improve.

An effective treatment against anthracnose consists of the application of fungicides:

20% mancozeb + 30% Cu oxychloride ( 0.3 to 0.5 %)  etc.

 Mildew (Phytophthora infestans):  is a very common disease of crops and also one of the diseases of potatoes. In this plant it affects the aerial part of the potato. Pale colored spots appear on the leaves, which over time darken and wrinkle the leaf. If conditions permit, a white or grayish powder develops on the leaves.

Downy mildew on tomato plant

Rhizoctonia (Rhizoctonia solani):  a compact mass of black mycelium appears on the tubers, producing malformations in the potato. The greatest damage occurs in spring. The disease is noticeable when you see potato plants of different sizes, totally unequal.

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