Differential responses of Meloidogyne spp. to Pasteuria isolates over crop cycles

Abstract

In the present study examining the interaction between Meloidogyne spp. and Pasteuria isolates over three crop cycles, significant differences were observed in eggmass production, root galling, plant root weight, endospore production, and parasitism rates. Higher eggmass production was noted in the Meloidogyne blend treatment, whereas M. incognita showed a marked decline after the third cycle. Root galling varied significantly with nematode populations and Pasteuria isolates, showing notable interaction effects (P0.01). The Meloidogyne blend treatment exhibited the highest gall rating, while M. javanica and M. incognita treatments with Pp3 and PpEcu isolates resulted in lower galling. Fresh root weights of tomato plants differed significantly in the presence of Meloidogyne spp. and Pasteuria isolates, with significant interactions observed (P0.05). Greater root weights were recorded in M. javanica and M. incognita treatments with Pp3 and PpEcu isolates. The production of Pasteuria endospores in Meloidogyne females also showed significant variability across crop cycles (P0.01), with M. incognita and PpEcu treatments yielding the highest endospore numbers. Moreover, parasitism of Meloidogyne females by Pasteuria was significantly influenced by nematode population and isolate presence (P0.01). Higher numbers of infected M. incognita females were found in PpEcu treatments. Final female populations of Meloidogyne spp. varied significantly under Pasteuria influence, with the Meloidogyne blend treatment showing the highest population and M. incognita under PpEcu the lowest. The results highlight the complex interactions between nematodes and the bacteria, emphasizing the potential of Pasteuria isolates to influence various aspects of Meloidogyne spp. development.