Description

Abstract: Greenhouse and microplot experiments were done to determine the effects of Meloidogyne hapfa and M. nrenrtaria on the severity of Cylindrocladium black rot (CBR), caused by Cylindrorlodium crotalariae, in the peanut (Arochis hypogaeu) genotypes Florigiant, NC IOC, NC Ac 18416, and NC Ac I8Qlb. In the greenhouse, severity of black rot was increased in Florigiant by either M. hapla or M. urenaria in treatments with fungal inoculum densities of 0.05 and 0.5 microsclerotia per gram of soil. Severity of black rot was not affected by these nematodes on NC 10C or NC Ac 18016. In microplots, disease ratings of roots from NC IOC, NC Ac 18416, and NC Ac 18016 were higher in plots infested with either nematode species and C. crorahrirre than in plots wich C. rrotalariae alone. In Field studies, initial and late-season populations of root-knot juveniles were correEaled with incidence of CBR and area under disease progress curves for some genotypes, but results were not consistent from 1986 to 1987.