Effects of fluctuating temperatures and different host plants on development of Pasteuria penetrans in Meloidogyne javanica

Greenhouse and growth room experiments were conducted to investigate the ef fect of host plant in relation to different nematode inoculum levels, and t emperature fluctuations on the development of Pasteuria penetrans. Host pla nt affected die development of P. penetrans indirectly through its effect o n nematode development. Endospores collected from Meloidogyne javanica fema les reared on different hosts did not show any differences in subsequent at tachment and infectivity. The numbers of endospores produced per infected f emale were reduced with increasing numbers of females parasitizing okra and tomato roots. Fluctuating temperatures retarded the development of P. pene trans. The life cycle of the parasite was completed faster at approximately constant temperatures close to 30 degrees C than when the temperature fluc tuated away from 30 degrees C. The temperature of irrigation water did not affect the duration of life cycle of P. penetrans.