Potato Diseases and Pests, Symptoms, Control Methods

Introduction to Potato Diseases and Pests

Are you growing potatoes on large scale? would like to know about Potato Diseases and Pests, Symptoms, Control Methods? the read the following.

The potato is the most popular common crop in India. Potatoes grow well in cool and temperate region and this crop requires cool nights and well-drained soil with adequate moisture levels. The potato crops cannot tolerate a  warm and tropical environment.

Read: Frequently Asked Questions About Potato Farming, Planting.

Pests in Potatoes:

Potato Tuber Moth: These are small insects in grayish brown color about 12 mm long. When they are fully grown, they look like caterpillars in pink or in pale green color.

• Symptoms: this insect creates bores in petioles and terminal shoots. They damage the tuber in the fields and in storage also. These caterpillars bore the tubers and feed on pupal. Black excreta on eye buds are the will project you the presence of the pest.
• Prevention: earthing up the crop regularly and covering the exposed tubers will reduce the infestation to some extent. Applying organic pesticides with quinalphos or carbaryl after planting to control pests. To protect the storage potatoes from this pest, store them well-ventilated, cool and dry place. You can cover potatoes with 2 inch layer of sand which is a very effective method.

Potato Cut Worms: these are medium sized moths with grayish brown lines with creamy white wings. These moths are attracted to light, and fully-grown caterpillar turn to black color. These insects will coil with touch. These pests damage plants and tuber.   These mainly attacks the young plants. The affected tubers have boreholes.

• Prevention: Good sanitation and mechanical destruction can reduce infestation. Proper irrigation can reduce the effect of pests. Treat the soil with organic chlordane or heptachlor will work against the infection. The insecticides like coragen or tracer can cure these pests.

Epilachna Beetle of Potato: these beetles have a unique shape with pale brown color with black spots. The grubs will be in yellow color.

• Symptoms: Both the beetles and grubs will feed on the leaf chlorophyll can create patches on the leaves.
• Prevention: these pests can be picked at the early stages. Use some organic pesticides like neem cake or groundnut cake, which work well in reducing the pest population.

Aphids: Aphids are tiny yellow insects.

• Symptoms: aphids will puncture the leaves and suck their juices. These pests damage young leaves and shoots. Severe infection will wilt and dry the shoots.
• Prevention: Use organic insecticide sprays to control aphids. Treat the soil with thimet before sowing seeds. Encourage the predators (ahelinus, ahidius or ladybird beetles) that feed on aphids.

Jassids: the adult pests are in yellow color with front wings. The nymphs will be in light green color.

• Symptoms: Both the nymphs and adults will feed on leaves and they suck all the juices. The infected leaves will curl that show adverse effect on plant growth on yields.
• Prevention: Treat the seeds with imidacloprid or cruiser. Use some organic insecticides to treat. Spray the crops with Rogor or metasystox or dimecran to control jassids.

Thrips: Thripsare delicate insects in light yellow color with wings. Adult thrips are about 11mm long and nymphs are minute and wingless. The thrips will destroy the leaves and suck the sap. They damage the young leaves and shoots. The infected leaves will curl and turn to blackish silver color. Severe infestation will make the leaves wilt and dry out.

• Prevention: Proper irrigation. Mulching with black, silver material. And using organic spray with tracer, phosphamidon, dimethoate can control pests effectively.

White Grub of Potato:

White grubs are larva of beetles. They grow upto 2 to 3 cm in a c shape with 3 leg pairs and brown color head.

• The infected tubers have irregular holes. Grub don’t live inside tubers.
• Prevention: Destroying infected parts. Use some bird predators which can control grubs to some extent. Flood the before planting tubers. Don’t choose the field covered with grasses.

Read: Growing Potatoes In Containers.

Diseases in Potatoes:                   

Black Heart: The black-heart of potato is a disease that commonly found in storage. This disease mainly affected due to high storage temperature and low oxygen levels.

Prevention:

• Well-drained soil and limited irrigation will control this disease in the fields.
• If growing potatoes in hot soil, early harvest will prevent this disease.
• Good ventilation increases the gas exchange, and dry crops quicker which prevents condensation.

Black Leg and Soft rot: Rot at lower stem region is the main symptom of this disease. Cool, damp conditions will encourage this disease. Soft rot occurs when the bacteria enters through wounds & other entry points. The bacteria will dissolve into the cell walls and liquefy the tuber. Cool and humid conditions will encourage this disease.

• Prevention: This viral disease is tough to control as it survives for long term on seed tubers and in soils. This can be controlled by using free seed tubers that can minimize the disease incidence. Or you can treat the seed tubers with organomercurial compounds or Boric Acid. Crop rotations with wheat, pea, oats, barley, lupin, soybean, sorghum and Bajra will control the disease development.

Black Scurf:  it is a soil borne fungal disease which infects plant tissue, which reduces tuber production and yield. This infects tubers causing black scurf, which reduces tuber appearance. High temperatures and moisture will encourage this disease.

• Prevention: Use only healthy tubers for planting. Treat the tubers with aretan or agallol before planting. Treat the soil with Brassicol, treating both planting tubers and soil can control the diseases efficiently.

Black Heart: The root cause due oxygen deficiency in the tubers. When the tuber doesn’t receive enough oxygen. The tissue inside the tubers will die from the inside out and turns to black color. Tubers affected with black heart will rot later.

• Prevention: Well-drained soil and controlled irrigation methods. If growing in hot soil, harvest early. In storage, give proper ventilation, drying the tubers quickly will prevent condensation.

Viral Diseases: Potato virus causes stipple streak. It is mainly affecting the plants in the early season, infected plants have veins, rough leaves, mild mottling and with tiny spots on the leaves.  This disease is mainly transmitted through aphids.

• Prevention: use only healthy and certified tubers. Do not use very small sized tubers for planting as they infected quickly. Inspect the field regularly and pick the infected plants. Use the organic sprays withMetasystox or Rogorthat can control the insects that spread this disease.

Read: Growing Mushrooms.