Location: Crop Protection and Management ResearchTitle: Natural suppression of Meloidogyne incognita by Pasteuria penetrans in cotton
|Timper, Patricia - Patty|
|LIU, CHANG - University Of Georgia|
Submitted to: Journal of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: 7/20/2015
Publication Date: 12/5/2015
Citation: Timper, P., Liu, C. 2015. Natural suppression of Meloidogyne incognita by Pasteuria penetrans in cotton. Journal of Nematology. 47:273.
Technical Abstract: The endospore-forming bacterium Pasteuria penetrans is an obligate parasite of root-knot nematodes (Meloidogyne spp.). This bacterium is commonly found in agricultural soils and has been associated with suppression of Meloidogyne spp. In a field site naturally infested with both P. penetrans and M. incognita, we evaluated the effect of tillage and fumigation with 1,3-dichloropropene (1,3-D) on the abundance of P. penetrans spores from 2011 to 2014. We also determined whether there was a relationship between the abundance of spores and root galling in cotton. The experiment was a split-plot design with tillage (strip vs conventional) in the main plot and frequency of 1,3-D application in the subplot. There were five 4-year sequences of fumigation (C=no fumigant; F=fumigant): C-C-C-C, F-F-F-F, F-C-F-C, F-F-C-F, and C-F-F-C. Abundance of spores was determined in the spring after tillage/fumigation using a bioassay and average root-gall indices on cotton plants were determined in the fall at the time of cotton harvest. Spore abundance was greater in the C-C-C-C plots than in most of the fumigation sequences; tillage had no effect on abundance of P. penetrans spores. The number of spores per assay nematode was 4.9 in C-C-C-C and 2.4 averaged across fumigation treatments. There was considerable year-to-year variation in abundance of spores with a range of 11 spores/assay nematode in 2012 and 0.4 spores/assay nematode in 2014. When analyzed within a fumigation sequence, spore abundance in the spring was inversely correlated (P < 0.0001) with root galling the following fall. Fumigation with 1,3-D had only a minor effect on abundance of P. penetrans spores compared to the year-to-year fluctuation in abundance of spores.