Prevalence of Pasteuria Sp. on Reniform Nematode In a Georgia Cotton Field

Pasteuria species are bacterial parasites of nematodes and have been associated with suppression of root-knot, sting, and cyst nematode populations.  Little is known about Pasteuria infecting the reniform nematode.  While sampling a field study near Cochran, GA, we found Pasteuria spores adhering to vermiform stages of the reniform nematode.  Soil samples were collected in November 2009, June 2010, and October 2010 to determine the prevalence of Pasteuria in locations differing in slope, soil texture, and nematicide application.  The average number of spores per nematode was used to estimate abundance of Pasteuria.  Fewer Pasteuria spores were observed in the sandiest areas of the field and in locations treated with Telone than in the other locations.  Similar numbers of spores were observed in the Temik treatment and the control, and there was no effect of slope on spore abundance.  It is likely that there was greater leaching of spores below the sampling zone in the sandier areas.  Telone reduced populations of the reniform nematode, thereby reducing the number of available hosts for Pasteuria.  Mature spores of Pasteuria were observed within the body of juveniles and pre-infective females indicating that the bacterium can complete its lifecycle before plant infection occurs.