Young Southern Pea Problems: Learn About Cowpea Seedling Diseases

Young Southern Pea Problems: Learn About Cowpea Seedling Diseases

By: Liz Baessler

Southern peas, often also called cowpeas or black eyed peas, are tasty legumes that are grown both as animal forage and for human consumption, usually dried. Particularly in Africa, they are an extremely popular and important crop. Because of this, it can be devastating when southern pea seedlings fall ill. Keep reading to learn more about recognizing diseases of young cowpeas and how to treat cowpea seedling diseases.

Common Diseases of Young Cowpeas

The two most common young southern pea problems are root rot and damping off. These problems can both be caused by three different pathogens: Fusarium, Pythium, and Rhizoctonia.

If the disease hits the seeds before they germinate, they will likely never break through the soil. If dug up, the seeds might have soil clumped to them by very thin threads of fungus. If the seedlings do emerge, they often wither, fall over, and eventually die. The stems near the soil line will be waterlogged and girdled. If dug up, the roots will appear stunted and blackened.

The fungi that cause root rot and damping off of southern peas thrive in cool, moist environments, and when the soil contains large amounts of undecomposed vegetation. This means you can usually avoid this southern pea seedling disease by planting your seeds later in the spring, when the soil has sufficiently warmed up, and by avoiding poorly draining, compacted soil.

Avoid planting seeds too closely together. If you see symptoms of root rot or damping off, remove the affected plants and apply fungicide to the rest.

Other Cowpea Seedling Diseases

Another southern pea seedling disease is mosaic virus. Though it may not show symptoms immediately, a plant infected young with mosaic virus may become sterile and never produce pods later in life. The best way to avoid mosaic virus is to plant only resistant varieties of cowpea.

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Read more about Black Eyed Peas


Controlling Pests and Diseases on Pea Plants

Related To:

Wilt attacks plants from the inside and causes rot

Wilts attack a plant from inside, leaving it unable to move water through its stem and leaves.

Once your peas are off to a healthy start, you'll want to ensure they continue to thrive. Protect and maintain the plants by taking these simple yet effective steps:


This disease produces resting spores, which persist in the soil and initiate primary infections in young pea plants. Though secondary infections can develop, particularly in cool, damp conditions, they are rarely as damaging as primary infections, which can kill plants before flowering. Fungicide seed treatment should be combined with varietal resistance to avoid serious losses. There are no foliar fungicides which give effective control.

Aphids can cause severe yield loss when present in large numbers, and early infestations can result in crops becoming infected with pea enation mosaic virus. For virus management it may be necessary to apply insecticides prior to flowering when aphids are present in low numbers. Aphids should be controlled to prevent feeding damage as soon as colonies can be found on 20% of plants, particularly where crops have commenced flowering. Yield can be improved by controlling aphids at any stage up to the time when four trusses of pods have been set.


Viruses

Alfalfa mosaic

FIGURE 1 – Yellow mottling of foliar tissue
Photo: L. Porter, USDA-ARS Prosser, WA

• Yellow mottling of foliar tissue (not always prominent)
• Purple or brown streaks in leaf veins
• Dead tissue on leaf or stem

FACTORS FAVORING DEVELOPMENT

• Presence of pea and green peach aphids, which transmit the virus
• Proximity to alfalfa fields

IMPORTANT FACTS

• Pea, green peach, foxglove, bean and potato aphids transmit the virus
• No resistant cultivars are available
• Insecticides may reduce secondary spread of virus by killing vectors (aphids)
• Can be confused with pea streak virus

Bean leaf roll or pea leaf roll


FIGURE 1 – Yellow, distorted and twisted leaves
Photo: L. Porter, USDA-ARS Prosser, WA

FIGURE 2 – Down-curled leaves
Photo: L. Porter, USDA-ARS Prosser, WA

FIGURE 3 – Yellow and distorted new growth old growth is normal
Photo: L. Porter, USDA-ARS Prosser, WA

AUTHORS: Lyndon Porter

• Plants are yellow and stunted
• New tissue is distorted and twisted while old growth may be normal
• Leaflets curl downward and are brittle

FACTORS FAVORING DEVELOPMENT

• Presence of pea aphids transmitting the virus

IMPORTANT FACTS

• Virus is not seed-transmitted
• Often occurs with pea enation mosaic virus
• Later infections are less likely to have an impact on yield
• Cultivars with resistance may be available
• Can be confused with other viruses, root rots, herbicide damage or abiotic stress

Pea enation mosaic


FIGURE 1 – Leaf with mosaic pattern of white/clear spots (windows)
Photo: L. Porter, USDA-ARS Prosser, WA

FIGURE 2 – Misshapen pods
Photo: L. Porter, USDA-ARS Prosser, WA

FIGURE 3 – Enations (bumps) on leaf
Photo: L. Porter, USDA-ARS Prosser, WA

• Leaves may be brittle and have a mosaic of green and yellow rough bumps (enations), translucent spots or clear veins
• Pods may be distorted and fill poorly

FACTORS FAVORING DEVELOPMENT

• Presence of pea aphids transmitting the virus

IMPORTANT FACTS

• Virus is not seed-transmitted
• Often occurs with bean leaf roll virus
• Early infections more severely impact yield than late infections
• Insecticides may reduce secondary spread of virus by killing vectors (aphids)
• Can be confused with other viruses, herbicide damage

Pea seedborne mosaic

Pea seedborne mosaic virus

FIGURE 1 – Deformed growth
Photo: L. Porter, USDA-ARS Prosser, WA

FIGURE 2 – Seed with water soaking and scarring symptoms
Photo: A. Beck, NDSU

FIGURE 3 – Delayed maturity of infected plants
Photo: M. Wunsch, NDSU

AUTHORS: Lyndon Porter, Kevin McPhee and Julie Pasche

• Leaves may curl downward
• Plants are stunted with a rosette appearance on new growth
• Pods may be deformed and fill poorly
• Seed may be water-soaked, scarred or cracked
• Maturity of infected plants is delayed

FACTORS FAVORING DEVELOPMENT

• Presence of pea, green peach or potato aphids, which can transmit the virus
• Infected seed

IMPORTANT FACTS

• Virus is readily seed-transmitted
• Virus infects many plants, including lentil, chickpea, alfalfa and vetch
• Manage by planting virus-free seed and resistant cultivars
• Insecticides may reduce secondary spread of virus by killing vectors (aphids)
• Can be confused with other viruses or herbicide damage

Pea streak

FIGURE 1 – Malformed pea pods with blistering
Photo: L. Porter, USDA-ARS Prosser, WA

FIGURE 2 – Purple sunken streaks on infected plants
Photo: L. Porter, USDA-ARS Prosser, WA

• Purple to brown streaks on leaves, stems and pods
• Leaf-yellowing and dieback of growing tips
• Pods may appear blistered, deformed and fill poorly
• Streaks on pods differ in size and shape and often are sunken

FACTORS FAVORING DEVELOPMENT

• Presence of pea or green peach aphid transmitting virus

IMPORTANT FACTS

• Virus is not seed-transmitted
• Virus also can infect alfalfa, red and white clover, and vetch
• Rarely associated with significant damage in pea fields
• Insecticides may reduce secondary spread of virus by killing vectors (aphids)
• Can be confused with other viruses, herbicide or abiotic damage


Harvest When the Shell Changes Colors

Harvesting peas is fun and easy, but there are a few things to think about when picking peas. First, peas are bushy plants and the pods are often hiding under the leaves. Use your hand to brush the leaves out of the way as you work your way from one side of the plant to the other. You can also bend down and look up to see hidden pods. Pea pods snap off easily and you can use your fingers to pick them. If you use a knife, be sure it's clean and disinfected of any disease that might spread from plant to plant.

You can tell if pea pods are ripe by looking and feeling for their fullness. Southern peas are ready when the shells begin to turn colors. Many begin to turn yellow or tan, but purple-hulled turn a dark purple or wine color. If you want to use the peas when they're fresh, pick them while they're still moist inside. If you plan on storing them for the winter, wait until they dry out and the pods begin to rattle. Just remember, to get more peas you need to keep harvesting them to trigger the plant to make more.

Peas can be harvested over the entire summer. To get the most peas out of your garden, plant peas every month during the growing season. This is called succession planting. Just make sure you compost your old pea plants to get the benefit of the nitrogen they release.


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