The factors affecting the detachment of Pasteuria penetrans spores on second stage juveniles of Meloidogyne javanica.

Abstract

In this study, investigations were made on some factors which can be responsible for the detachment of spores of the Pasteuria penetrans, the suggested biological control agent for Meloidogyne (root knot) nematodes, which attached to the cuticle of second stage juveniles. Initially, the common species of Meloidogyne nematodes infecting tomato plants, the life stages of Meloidogyne javanica, the life stages of bacterium P. Penetrans were identified. Then, the effect of the factors; age of the second stage juveniles, the initial spores attachment, the movement of nematodes, the ambient temperature and the remaining of spores in the soil were taken into consideration. The age, the movement, the ambient temperature and the remaining of spores in soil were found to influence the spore detachment. Spores did not detach from immobilized nematodes irrespective of their age. The temperature regimes of 0°C and 40DC seemed to have no effect, probably, due to the suspension of movements by inhibition of enzymic activity at these temperatures. 'The remaining of spores in soil seemed to condition spore for a better attachment probably by the removal of outer covering and exposing the adhesive fibers. This conditioning may be attained by the microbial activities occurring in soil and can be achieved in the laboratory by a method like sonication when spores arc obtained directly from adults females.