Potato Production Plan by GROWTECH

1. Late Blight of Potato:

Late blight caused by the fungus Phytophthora infestans is the most important disease of potato that can result into crop failures in a short period if appropriate control measures are not adopted. In the initial stages of an attack, small grayish-brown spots appear on the edges and corners of leaves, which later spread and cover the entire leaf. The disease spreads more in humid weather, and affected areas emit a foul odor due to the wilting of affected parts. Tubers are also affected by this disease on their own, and develop blackish-brown spots. Infected seeds play an important role in spreading the disease to new crops. In the field, the disease spreads through water and air from infected plants to healthy plants. Moisture in the air and temperatures around 20-25 degrees Celsius are beneficial for the severity of the disease.

Mode of disease spread:

The main cause of the spread of this disease is infected seedlings. In the absence of the potato crop, this fungus survives on the remains of the plant such as leaves and stems in the field. When the new crop is planted and there is moisture in the soil, the fungus produces spores that attack the leaves and stems. High humidity and temperatures between 10-25 degrees Celsius are ideal conditions for the spread of germs and to infect new leaves, making it a major threat to the potato crop.

Disease Management:

• Burn or dispose of rotten plants.
• Spray suitable fungicide on the crop.
• Try to insure crop rotation to overcome the disease spread

2. Early Blight of Potato:

This disease spreads from a particular type of fungus Alternaria solani. Usually, its attack is more severe in rural areas, but due to the transfer and transportation of potatoes from one area to another, the disease also affects mountainous regions. Deep brown spots appear on the leaves, and central circles become visible on the tubers when the severity of the disease increases. The attack of the disease first occurs on the lower leaves, and in severe cases, all the leaves fall off, and infected potatoes cannot be stored for long.

Symptoms:

The disease that spreads due to fungus appears as brown and dark circular spots on both leaves and stems. Black and dry spots also appear on potatoes due to this disease. The edges of these spots are clearly visible. When these spots increase in number, they merge with each other and completely destroy the plant's surfaces. If the temperature is between 24 and 30 degrees Celsius, this disease spreads rapidly. The fungus not only survives inside the seed but also in the soil for many years.

Mode of Disease Spread:

The fungus responsible for this disease can survive not only on the potato crop but also on other plants of the potato family, such as leaves, small tubers, and other potato plants, in the absence of the potato crop. When the temperature is suitable (between 20-30 degrees Celsius) during the plantation of the new crop, this disease attacks the crop severely. Weak, injured, and nutrient-deficient plants are mostly affected by this disease.

Disease Management:

• Burn or dispose of rotten plants.
• Spray suitable fungicide on potato crop.
• Crop rotation practice overcome the disease effects.

3. Potato Wilt:

Potato wilt is a disease that spreads due to a fungus. It is found in agricultural and mountainous areas, and it is responsible for the failure of potato crops. The lower leaves turn yellow first, and then wilting occurs gradually on the entire plant. In severe cases, the roots and stems also rot. The disease attacks during the spring season (February to May) in plain areas and during the August season in mountainous areas. In case of wilting, the stems and roots of the plant become slightly brownish in color, and a yellow ring appears on the upper part of the resulting tubers, which is visible when they are cut. The disease spreads to the next season's crop if infected potatoes are planted. The disease becomes more severe with higher temperatures and humidity.

Mode of Disease Spread:

The fungus responsible for this disease is typically found in infected tubers or can spread from one field to another through contaminated equipment or irrigation water. The fungus initially affects the roots of potato plants and later spreads to the stem, eventually infecting healthy plants as well. The disease tends to be more severe in dry weather conditions and when the temperature is between 15-20°C.

Disease Management:

• Use healthy seeds only
• Seed Treated with suitable fungicide 2g / liter water before sowing.
• Crop rotation for minimum of three years

4. Phytoplasma:

Phytoplasma is a new but very harmful disease that does not spoil the potato crop only but also affects their yield. The leaves appear small and curved towards the apex. In more severe cases, the upper part of the plant resembles a tent, and although potatoes are still produced, they are smaller and less frequent. Frost does not seem to affect the plants at all. The color of the leaves is typically dark brown.

Disease Management:

• Use healthy seeds and remove affected plants.
• This disease also spreads due to the attack of Jassid, so needs to control this insect first.
• It is advised not to cultivate potatoes in the affected field for 2-3 years.

Control measures:

Azoxystrobin+ Tebuconazole 50% 100ml/acre
Or
Trifloxystrobin+ Tebuconazole 75% 65 gram/acre

5. Stem/ Rhizoctonia canker:

This is a fungal disease that spreads through the soil and attacks the roots of potato and other plants. It spreads more during warm and humid weather. Black, swollen lesions appear near and under the soil on the roots of plants. The affected parts of the plants turn black. Black lesions also start to appear on the potatoes, which are not clean. The underground stem also starts turning black.

6. Black leg of Potato:

This is a disease of potatoes that spreads through the Black-leg bacteria. As a result of the attack, the leaves wilt, yield decreases, and the plant weakens. The stem and underground part of the potato turn black. The disease is more prevalent in the final stages of crop growth. In case of severe attack, tubers also get affected. The potatoes become soft and emit a foul smell. This disease is transmitted through seeds.

Disease Symptoms:

If the humidity is high, these bacteria can attack the crop even during the growing season. As a result of the attack, there is a wilting of the leaves, a decrease in yield, and the top portion of the plant becomes blackened. This disease is transmitted through the seed. The plants are affected by this disease, wilt and the smell of decay is produced. New potatoes are also infected and are smeared with decayed parts attached to the root. The leaves of the spring plant wither and die, and eventually it causes spread of disease to nearby healthy plants. If a wound occurs on the tuber during the storage or under field conditions, there are likely more chances for occurrence of this disease. This disease may spread from one tuber to others during storage conditions as well. If the attack is severe, rotting of tubers occurs.

Mode of Disease Spread:

The disease affects most of the plants or potatoes that are infected with it. Once these potatoes are planted, they spread the disease through irrigation water to nearby plants, causing them to become infected. If the temperature is between 3 and 35oC, the risk attack of this disease increases when one crop of potatoes is followed by another. The potato crop can be protected from this disease by growing it at a temperature of 23 to 25 degrees Celsius in dry and warm soil. In stores, this disease can spread rapidly and attack with intensity.

Disease Management:

• Use healthy seeds and remove affected plants.
• This disease spreads through the Jassid insect, so control it.
• Do not cultivate potatoes in the affected field for 2-3 years.

7. Angular Leaf Blight:

This disease commonly attacks cucumbers, but it can also be found on other vegetables. Initially, yellow spots appear on the plants, which later turn brown. The infection eventually dries up and breaks off. The spread of the disease occurs through the bacteria present on the infected plants and by air. Rainfall accelerates the spread of this disease.

8. Potato Leaf Curl Virus:

Potato Leaf Roll/Curl Virus (PLR/CV) was once the most common virus in potato seed stocks and also caused the greatest yield loss in potato (specially stored potato).

Symptoms:

Initial transmission occurs when plants get infested and fed upon by virus-carrying aphids during the growing season. Secondly, plants grown from infected seed develop rolled margins of lower leaves, which become crisp and dry.

Biological Control:

Reducing aphid population by means of predator is a helpful preventive measure. Ladybirds, solider beetles and some type of flies eat adults of aphid and larvae.

Chemical Control:

Chemical treatment of potato leaf curl virus is not possible. However, the aphid population can be controlled to some degree.

Preventive Measures:

• Use seed tubers from healthy plants.
• Plant resistant varieties if possible.
• Monitor the field, pick and destroy diseased plants.
• Destroy weeds and volunteer plants that can host the virus and feed the aphids.

9. Potato Y Viral Disease:

Potato Virus Y (PVY) is a monopartite, single stranded RNA virus that infects mainly Solanaceous plants including, potato, tomato, pepper, tobacco and eggplant. There are multiple strains of the virus including the common strain, PVYO, which causes mosaic symptoms in most hosts.

Symptoms:

The virus is transmitted by aphids. This spread is mainly local as aphids lose the ability to transmit the virus after 12 hours. Infected tubers are the main source of virus inoculum. Dark spots or streaks appear on infected leaves before they fall off (leaf drop streak) leaving a bare stem with a tuft of mottled leaves at the top. Plants grown from infected seed are stunted, pale and mottled, with small, crinkled and twisted (rugose) leaves.

Control:

• Less susceptible varieties can be selected.
• Plant certified seed
• Treat with application of soil-applied and foliar insecticides to control the aphid vectors.
• Destroy weeds and volunteer plants that can host the virus and feed the aphids.

10. Potato A Viral Disease:

PVA is a virus transmitted by many aphid species in the non-persistent manner. As in the case of PVY, PVA can be acquired by M. persicae in less than one minute and transmitted to another leaf equally rapidly with no latent period. Virus A is widespread in most potato-growing countries but it is considered much less important than PVY. Most cultivars are resistant and yield losses are usually low even if the level of infection can reach up to 40% in some cultivars or in the case of co-infection with other viruses.

Control:

• Less susceptible varieties can be selected as documented on National List
• Plant certified seed
• Treat with application of soil-applied and foliar insecticides to control the aphid vectors.
• Destroy weeds and volunteer plants that can host the virus and feed the aphids.

11. Common Scab:

The main source of the disease is infected soil. Potato scab is caused by a bacterium-like organism, Streptomyces scabies that overwinters in soil and fallen leaves.

Symptoms:

Shallow and irregular spots on the tuber, occasionally with a raised appearance. Deep cracking and pits develop in severe cases.

Control Measures:

• Avoid raising soil pH levels with lime prior to growing potatoes
• Plant disease free tubers
• Irrigate when soil moisture is high and allow the crop to dry out before harvest
• There is no chemical treatment available.

12. Powdery Scab:

This disease attacks the potato crop in cold and moist soils, especially in soils with a pH of 6.5 or higher.

Symptoms:

This disease affects the stems and parts of the plant uniformly. At the beginning of the disease, small, blister-like, brownish spots appear on the potatoes, which later turn into wounds. However, the fully-grown potatoes are present in the form of brown scabs that later become the cause of the spread of the disease.

Mode of Disease Spread:

The hard seed fragments resulting from preparatory measures remain present in the remaining crops from the previous season for a long time and eventually become the cause of disease spread. The disease can also spread through affected seeds. It spreads easily at a temperature range of 25-30oC.

Disease Management:

• It is advisable to use disease-free seeds.
• The disease can be controlled by maintaining suitable and moist soil during the stages of potato formation. This reduces the risk of fungal infection during cultivation
• In fields where this disease has been observed, it is recommended to rotate suitable crops for at least three consecutive years.
• Used plant varieties with better disease resistance.