The multiplication of Longidorus elongatus (de Man) on different host plants with reference to virus transmission

Abstract

SUMMARYIn pot tests, Longidorus elongatus (de Man) populations increased rapidly on Fragaria vesca, Stellaria media, Mentha sativa and Lolium perenne and slightly on Brassica rapa (turnip var. White globe) and on Ribes nigrum; but on Rubus idaeus populations declined at the same rate as in fallow soil. Raspberry ringspot (RRV) and tomato black ring (TBRV) viruses were readily transmitted by L. elongatus to S. media, TBRV only was transmitted to L. perenne, and M. sativa became infected with neither virus. RRV was transmitted to R. idaeus var. Mailing Jewel, on which the nematode fed but evidently did not reproduce.In a field experiment L. perenne and Fragaria ananassa (strawberry) vars. Huxley and Redgauntlet were shown to be good hosts for L. elongatus and R. idaeus (raspberry) vars. Lloyd George and Mailing Jewel were confirmed as non‐hosts, together with Rheum rhaponticum (rhubarb). Two periods of egg laying were detected each year in the Redgauntlet strawberry plots and these coincided with the growth of young roots during the late spring and autumn.The wide host range of L. elongatus among cultivated plants and weeds, together with its ability to survive long periods without food, precludes the use of crop rotation as a means of control. Chemical soil sterilization is considered the most effective means of control because it can greatly decrease L. elongatus populations and as the nematode multiplies slowly, even on favourable host plants, several years are likely to elapse before populations become large enough to spread viruses effectively from infector plants to susceptible crops.