Distribution of Rotylenchulus reniformis (Tylenchida, Hoplolaimidae) reproductive types in Kyushu, Japan

Abstract

The reniform nematode Rotylenchulus reniformis Linford and Oliveira (Tylenchida, Hoplolaimidae) is a serious pest of a number of crops worldwide. Although different reproductive types of R. reniformis populations have been reported in Japan, there is no information regarding the difference in their pathogenicity. In this study, we investigated the distribution of R. reniformis reproductive types primarily in sweet potato fields in Kyushu for a further study on their pathogenicity. Rotylenchulus reniformis was widely detected in sweet potato fields, but there were variations in its density and male frequency. DNA amplification conducted using primers designed to distinguish the male-absent type from the male-numerous type revealed that male-rare populations in Kumamoto were the male-absent type, but a population from Saito, Miyazaki, was a mixture of both types. Although R. reniformis density was high in some fields at the harvest time in Kumamoto and Saga, there was no apparent damage to sweet potato.