Studies on the Efficacy of Heterogeneously Produced Pasteuria Penetrans (PP3) Isolate over Individual Pasteuria Isolates in the Spore Attachment, and Pathogenic Potential on Three Meloidogyne Species

Abstract

The aim of the present test was to develop a Pasteuria penetrans isolate (Pp3) on a Meloidogyne blend and compare the attachment and pathogenic potential of this heterogeneously produced isolate with other Pp3 isolates produced on individual Meloidogyne species (Meloidogyne javanica, M. incognita and M. arenaria). Number of spores attached varied among Meloidogyne spp. Pp3 isolate originally multiplied on M. javanica showed greater attachment level with second stage juveniles (J2s) of M. javanica (13.8) than other Meloidogyne spp. tested and lesser attachment was observed on J2s of a M. arenaria. The Pp3 isolate showed variable influence on the Meloidogyne spp. in suppressing root-knot disease. There was a significant difference in numbers of eggmasses produced by females of Meloidogyne spp. Higher numbers of eggmasses were recorded with females of M. arenaria (370) while fewer numbers of eggmasses were observed in treatment where M. javanica (245) was present. Root galling differed significantly among treatments (P0.01) and higher gall infestation was recorded in M. arenaria treatment (6.2) while lesser galling was observed in M. javanica treatment (4.4). Final female population also varied among treatments (P0.05) showing higher numbers of females in M. arenaria treatment (456) and fewer with M. javanica (398). Parasitism of females of Meloidogyne spp. by Pp3 differed significantly among treatments. Higher numbers of females infected with Pp3 spores were recorded among females of M. javanica (14.4) while lesser numbers of parasitized females were observed in M. arenaria treatment (9.8). There were significant variations in numbers of endospores/female produced by females of Meloidogyne spp. however egg set data did not differ in the treatments. The results showed that the Pp3 isolate was more pathogenic on M. javanica compared with other Meloidogyne spp. (M. incognita, M. arenaria and M blend). The Pp3 isolate was found compatible with different Meloidogyne spp. while M. arenaria proved the least good host to bacterial parasite