Objective This study aims to clarify the parasitic and pathogenic characteristics of Radopholus similis on rice and maize, and provide a basis for assessing the potential risk of its occurrence and damage to rice and maize and for developing scientific control strategies.

Method Under a daily average temperature of 25 ℃ to 32 ℃, outdoor pot experiments were conducted using two rice cultivars, Nipponbare and Meixiangzhan 2, and a maze cultivar, Jinxi Sweet Corn, as hosts. Plants were inoculated with three populations of R. similis from different hosts at initial densities of 1000 and 2000 nematodes per pot, respectively. After 70 days, the nematode reproduction rate in the rice rhizosphere and rice growth parameters were determined, and after 60 days, the nematode reproduction rate in the maize rhizosphere and maize growth parameters were detected.

Result The results showed that all tested populations of R. similis infected the rice and maize root systems, completed their life cycle within the roots, and caused obvious symptoms in the infected rice and maize plants. All three nematode populations showed pathogenicity and harmfulness to both rice cultivars and maize, but there were differences in pathogenicity and damage severity among the nematode populations. Furthermore, the same nematode population exhibited differing levels of pathogenicity towards the two rice cultivars and maize. At an inoculation density of 2,000 nematodes per pot, the yield losses caused by infection with and damage from the SZ-FZ, SX-7, and GJ-LY323 populations were as follows: for rice cultivar Nipponbare, the panicle weight was reduced by 14.4%, 44.7%, and 42.2%, respectively; for rice cultivar Meixiangzhan 2, the panicle weight was reduced by 15.7%, 14.3%, and 17.5%, respectively; and for maize, the ear weight was reduced by 44.2%, 36.8%, and 42.4%, respectively.

Conclusion Rice and maize are hosts for R. similis. This nematode infects and lives as an endoparasite in the rice and maize root system, causing disease in the rice and maize plants. If it spreads to rice and maize field, it can damage rice and maize and lead to yield losses.