Are you growing cowpeas or southern peas? If so, you’ll want to know about Phymatotrichum root rot, also known as cotton root rot. When it attacks peas, it is called southern pea cotton root rot or Texas root rot of cowpeas. For information about cowpea cotton root rot and tips on root rot control for southern peas and cowpeas, read on.
About Southern Pea Cotton Root Rot
Both southern pea cotton root rot and Texas root rot of cowpeas are caused by the fungus
Phymatotrichopsis ominvorum. This fungus attacks thousands of broadleaf plants including southern peas and cowpeas.
This fungus is nearly always worse in calcareous clay loam soils (with a pH range of 7.0 to 8.5) in regions that are hot in the summers. This means that cowpea cotton root rot and southern pea cotton root rot are found largely in the southwestern United States, like Texas.
Symptoms of Texas Root Rot of Cowpeas and Southern Peas
Root rot can severely damage both southern peas and cowpeas. The first symptoms you’ll notice of southern pea or cowpea cotton root rot are reddish-brown spots on stems and roots. The discolored areas eventually cover the entire root and lower stem.
The plant foliage is obviously affected. They look stunted, with yellowing and drooping leaves. In time, they die.
The first symptoms appear during the summer months when soil temperatures soar. Yellowing foliage comes first, followed by leaf wilt then death. Leaves remain attached to the plant, but the plants can be pulled out of the ground easily.
Root Rot Control for Southern Peas and Cowpeas
If you are hoping to learn something about root rot control for southern peas and cowpeas, keep in mind that control of cotton root rot is very difficult. The behavior of this fungus varies from year to year.
One helpful control practice is buying high-quality pea seeds treated with a fungicide like Arasan. You can also use fungicides like Terraclor to help control root rot. Apply a quarter of the fungicide dose in the open furrow and the rest in the covering soil during planting.
A few cultural practices may help provide root rot control for southern peas and cowpeas as well. Take care during cultivation to keep soil off the plant stems. Another tip is to plant these crops in rotation with other vegetables.