Relation ofMeloidogyne haplaandMacroposthonia ornataPopulations to Cylindrocladium Black Rot in Peanuts

Publisher Website
Google Scholar
Abstract
Five field experiments were established in C. crotalariae-infested peanut fields from 1976 to 1978. Populations of Macroposthonia ornata, M. hapla and C. crotalariae microsclerotia were determined in each field 3 times during each growing season. Correlations between populations of these organisms and the severity of Cylindrocladium black rot (CBR) were analyzed using multiple regression models. In all tests, CBR-resistant cultivar NC3033 sustained less disease than CBR-susceptible Florigiant and final populations of microsclerotia were higher on Florigiant than on NC 3033. Correlations and the partial correlations of M. hapla and C. crotalariae populations with CBR severity were generally significantly positive on both cultivars. Correlations between macroposthonia ornata and the disease were either less pronounced than those with Meloidogyne hapla or not significant. Final populations of Macroposthonia ornata were consistently greater on NC3033 than on Florigiant. In microplot tests, C. crotalariae combined with M. ornata caused more disease on Florigiant but not on NC 3033 than did C. crotalariae in the absence of M. ornata. Reproduction factor (i.e., final population/initial population) for M. ornata, however, was higher on NC 3033 than on Florigiant.