Effect of soil properties and temperature on the nematode antagonistic potential of bacterial bioagent, Pasteuria penetrans against root knot nematode, Meloidogyne incognita

Abstract

The nematode antagonistic bacterium. Pasteuria penetrans is one of the proven and highly efficient biocontrol agents. A study was conducted to understand the influence of various abiotic factors. Five different soil types viz., alluvial, black, red, laterite and sandy were filled in paper cups (200g/cup) and freshly hatched second stage juvenile (J2) of root knot nematode, M. incognita (1000 J2/cup) along with 10 mg of root powder (1.84 x 106 spores/g) was thoroughly mixed and incubated at 25°C for 48 h. The parasitization was higher (95.5%) in sandy soil with a clay content of 6.0 per cent. Spore attachment of P. penetrans at four levels of temperatures viz., 15, 20, 25 and 30°C in red loamy soil was tested. Significant influence of temperature was observed in parasitization of second stage juvenile under 25°C (90.2%). A glasshouse experiment was conducted to study the influence of nematicides. Application of carbofuran along with P. penetrans increased the rate of parasitisation which was 83.1 per cent as against 61.0 per cent in P. penetrans treatment only. Influence of root exudates of host and non-host plants of M. incognita was tested on the parasitizing ability. The parasitizing ability significantly increased by 4.5 per cent in tomato root exudates and by 4.0 per cent in coleus. The host plant had influence over the number of spore attachment on J2. The results of these experiments paved way to exploit the nematode bacterial hyper parasite, P. penetrans for managing plant parasitic nematodes under varied soil environmental conditions.