Fumigation effects on bacterial populations in new golf course bermudagrass putting greens

Golf course putting greens in the United States are normally built with a root-zone mix composed of >80% sand and a peat source. Populations of seven aerobic bacterial groups, commonly associated with soil or plant roots, were monitored during the building, planting and establishment of miniature bermudagrass putting greens, with a different set of greens built in each of 2 years. At each phase of construction, including pre- and post-fumigation, the following bacterial groups were enumerated: fluorescent pseudomonads, Gram-positives, Gram-negatives, Stenotrophomonas maltophilia, actinomycetes, heat-tolerant and total aerobic. The fumigants methyl bromide, dazomet and metam sodium were used at either normal or 10× field rates. In both years, by 50–70 days after fumigation, which included 4 weeks after planting, the size of the populations for all of the bacterial groups were either greater than or similar to the size of the populations prior to fumigation. The sand source, peat source, and fumigant source and amount did not have any long-term detrimental effects on size of the populations of any of the bacterial groups evaluated.