Peanut Plant Diseases

Rhizoctonia Pod Rot

• Rhizoctonia pod rot is a fungal disease of peanuts caused by Rhizoctonia solani. The disease can affect the plants in all stages of growth and is characterized by the drying and browning of the pods. In cases of severe infection, only the vascular tissue on the pods is left. The fungus persists in infected seeds and causes death and damping off in new plants.

Phythium Wilt

• Pythium wilt infects peanut plants during August and is evident by the wilting of leaflets and petioles. The wilting foliage is yellow to light green in color with curled margins. As the disease progresses, foliage turns brown, falls and the pods start to rot. The roots of affected plants are stunted in growth and severe infection results in the death of entire plant. Rotating corn with peanuts and using rye and ryegrass as cover crop promotes the growth of the fungus in soil.

Cylindrocladium Black Rot

• Cylindrocladium black rot is caused by Cylindrocladium crotalariae. The disease symptoms start to appear between the middle and end of July and include stunted plant growth and yellowing leaves. The foliage first starts to wilt on very hot days and then gradually dies. Infected plants are either contained in specific areas of the field or are spread out through the whole planting site. The presence of reddish-orange, round, fungal spore-containing structures on stems and pods above or below the soil are also indicative of the infection.

Peanut Root Knot Nematode

• Peanut root knot nematodes (Meloidodyne arenaria) infest the roots of the peanut plants and lead to the formation of galls or raised tissues on the peanut pods and roots. In cases of severe infestation, pods develop black, wart like growth. This specific species of the root knot nematode is the most widespread root pest of peanuts in Florida, Alabama, Texas and Georgia, cites J. Starr, E. Morgan and C. Simpson of the Texas Agricultural Experiment Station.