Common Pests Of Potato Crop And How To Manage Them

By Author: Prashant Manne
Total Articles: 7
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Potato- Solanum tuberosum- is an herbaceous perennial plant grown for its edible tubers. It is the most important food crop in the world. It is a temperate crop grown under subtropical conditions in the Indian subcontinent. It is a rich source of starch and vitamins. Potatoes are used for many industrial purposes as well like in the production of starch and alcohol. It is grown in almost all the states, but the largest potato-growing states in India are Uttar Pradesh, West Bengal, Punjab, Karnataka, Assam, and Madhya Pradesh.

The potato crop is infested by a variety of fungal, bacterial, and viral diseases. Some pests attack the foliage while some attack the tubers. Many diseases in the potato plant are soil/seed-borne and are thus difficult to control once infected.

Some common pests and diseases affecting potatoes with their relevant solutions have been listed below.

**Early blight Alternaria solani**

Symptoms: Dark lesions with a yellow border which results in concentric rings of raised and sunken tissue on the leaves and stems; the lesions are initially circular but then ...
... become angular, leaves become necrotic but remain attached to the plant; dark, dry lesions on tubers with leathery texture and watery yellow-green margins appear.

Cause: Fungus

Management: The application of appropriate fungicides for potato blight in India can reduce the severity of foliar symptoms; fertilize and water the plants adequately to reduce stress; plant late varieties that are less susceptible to disease; store tuber in a cool environment.

**Late blight Phytophthora infestans**

Symptoms: Affected leaves appear blistered as if scalded by hot water- these leaves eventually rot and dry out; leaves turn brown or black in color; spots appear on the underside of leaves; affected stems begin to blacken from the tips and eventually dry out; in case of severe infections, all foliage rots, dries out and falls to the ground; affected tubers develop dry brown-colored spots on their skin and flesh.

Cause: Fungus

Management: Destroy all infected tubers and any volunteer plants; apply proper fungicides for potato blight in India; plant resistant varieties; adjust the watering time to reduce periods of leaf wetness; apply appropriate protective fungicides if the disease is forecasted in the area.

**Black scurf/ scab Rhizoctonia solani**

Symptoms: flat and irregular shapes black fungal bodies on tuber surface; tubers get misshapen; red-brown and black sunken lesions appear on sprouts; lesions may girdle the main stem that causes leaves to curl and turn yellow.

Cause: Fungus

Management: No potato varieties are completely resistant to the disease, the control relies on the reduction of the level of inoculum in both soil and tubers; application of good quality fungicides to seed pieces or soil; avoiding plantation of the seeds too deep in cold soils, and rotate the crop away from potato to reduce levels of soil inoculum.

**Cutworms Nephelodes minians and others**

Symptoms: The stems of young seedlings are severed at the soil line; if an infestation occurs later, irregular holes are eaten into the surface of the fruits; larvae causing the damage are usually active at night and hide during the day in the soil; larvae exhibit a variety of patterns and coloration.

Cause: Insects

Management: Remove all plant residue from the soil after harvest or at least two weeks before planting; plastic or foil collars fitted around the plant stems to cover the bottom 3 inches above the soil line and extending a couple of inches into the soil can prevent the larvae from severing the plants; hand-pick the emerged larvae after dark; spread diatomaceous earth around the base of plants as a barrier; apply appropriate insecticides for potato insects in India to the infested areas of the garden.

**Aphid Macrosiphon euphorbiae**

Symptoms: Small, soft-bodied insects on the underside of leaves and stems of plants that are usually green or yellow in color; if the infestation is heavy, it can cause leaves to yellow, or develop distorted, necrotic spots on leaves and stunted shoots.

Cause: Insects

Management: if the aphid population is limited to just a few leaves then infestation can be pruned out for control; check transplants before plantation; use tolerant varieties if available; use reflective mulches like silver-colored plastic that help deter aphids from feeding on plants; spray sturdy plants with a strong jet of water to knock aphids from leaves; use appropriate insecticides in case of heavy infestations.

Apart from the above-listed pests and diseases affecting the potato plant, there are also other insects like jassids and whiteflies that infect the plant in addition to various viral diseases. Viruses affect the seed quality and so they have a chain of implications. Thus, one should properly diagnose and control of pests & diseases is of utmost importance. It is important to remember that not all pests and diseases are present everywhere, some of them are more widespread in one region as compared to others.

To maintain the plant health, the use of proper potato plant biostimulants by Jivagro must be used. The nutrient requirement of the potato crop is quite high and the need for fertilizers and insecticides arises to maintain a healthy crop.