The best larvicidal activity
was observed in the S. racemosum treatment at a concentration of 50%, which caused a 96.7% mortality
rate. Under the pot conditions, compared to the untreated control, the application of S. racemosum combined
with P. lilacinus significantly stimulated the root length, shoot length and plant weight of cucumber
plants, and significantly fewer galls and nematodes were observed. Under the greenhouse conditions, the
combination of S. racemosum and P. lilacinus not only decreased the nematode severity but also increased
the cucumber yield compared to the untreated control. Among all the treatments, the combined application
of S. racemosum and P. lilacinus was more effective at controlling M. incognita than other treatments,
except for the fosthiazate treatment. The results indicate that the combined use of S. racemosum and P.
lilacinus represents a new biocontrol strategy against parasitic nematodes in protected agricultural areas.