Comparison of Isolates and Strains Within the Brown-Rot Fungus Genus Gloeophyllum Using the Soil Block Decay Method‪.‬

Abstract Eleven decay tests, using three isolates of Gloeophyllum trabeum, one isolate of G. separium, plus five pairings (co-cultures) of G. trabeum isolates, were conducted based on standard soil block decay test methods. After 12 weeks, the greatest mean weight loss achieved in southern yellow pine sapwood blocks was 47.5 percent with a pairing of two isolates of G. trabeum (wild type DR 397 X ATCC 11539). The lowest weight loss achieved was 19.1 percent with a wild type isolate (DR 274). A newly obtained (2001) isolate of G. trabeum (MAD 617) achieved significantly better weight loss (43.7%) than a culture of the same isolate that had been used in the current lab since 1991 (24.2%). The results indicate the variability of decay capability of Gloeophyllum isolates due to such factors as age, storage, and origin. Results also demonstrate the difficulty of achieving 50 percent or more weight loss in southern yellow pine sapwood by a selection of Gloeophyllum isolates under optimum conditions using standard test procedures. In addition, it was found that inserting the test block in the soil jar at the time of inoculation resulted in the same amount of weight loss as the standard method of inserting the test block 3 weeks after inoculation; the former method saves time and reduces contamination.