Major Cowpea diseases are:-
1. Cowpea Root rot and Damping off: Pythium, Rhizoctonia, Macrophomina
Symptom:
- Symptoms vary and include the rapid death of young succulent plants.
- Discoloration of taproots, longitudinal cracks of the stems, stunting, wilting and poor yields.
- Complete control of root rot and damping-off is difficult, and no variety of cowpea is resistant to root rot.
- The persistent damp weather before the development of the first true leaf and also the crowding of seedlings due to poor seed spacing may increase damping off.
Management:
- Soil application P. fluorescens or T. viride– 2.5 kg/ha + 50 kg of well decomposed FYM or sand
- Spot drenching with Carbendazim @ 1 gm/ litre
2. Cowpea Southern blight: Sclerotium rolfsii
Symptom:
- Southern blight is caused by a fungus that attacks roots and stems of cowpeas.
- The first visible symptom of Southern blight is a progressive, yellowing and wilting of the foliage beginning on the lower leaves.
- The plant dies within a few days.
- A brownish vascular discoloration inside dead stem may extend several inches above the soil line.
- During warm, moist conditions, the coarse, white mycelium of the fungus makes characteristic fan-shaped patterns of growth on the stem at the soil line.
- In this white-mat of the fungus, numerous smooth, round, light-tan to dark-brown mustard seed-like bodies called sclerotia are formed.
3.Cowpea mosaic: Virus
Symptom:
- Symptoms vary and include the rapid death of young succulent plants.
- Discoloration of taproots, longitudinal cracks of the stems, stunting, wilting and poor yields.
- Complete control of root rot and damping-off is difficult, and no variety of cowpea is resistant to root rot.
- The persistent damp weather before the development of the first true leaf and also the crowding of seedlings due to poor seed spacing may increase damping off.
Management:
- Roguing out of cowpea mosaic virus-diseased plants in the early stage of growing up to 30 days and spraying twice at fortnightly intervals with Monocrotophos 500 ml/ ha (or) Methyldemeton 25 EC 500 ml/ha.
4. Cowpea Fusarium wilt: Fusarium oxysporum
Symptom:
- Fusarium wilt usually causes the lower leaves on one side of the plant to turn yellow.
- Infected plants usually are stunted and wilted as the organism develops in the food and water conducting tissues.
- Brick red tissue can be observed in the stem when it is split lengthwise.
Management:
Fungal and viral diseases can be reduced by:
- Treating high quality seed with fungicides labeled for cowpeas.
- A four or five year rotation with other crops.
Source-
- TamilNadu Agritech Portal
