I love it when amateurs cite papers without reading them!
Nelson's paper clearly states that efficacy has been seen only in greenhouse studies, but NOT in the field. This is precisely for the reasons that were discussed ad nauseum
in all the threads about biologcial controls.
When these practices are taken to the field, they don't perform well because the conditions in the field do not support the necessary changes in microbial populations. If that environment could support those populations, they would have been there already!
Also, if you actually read the research that was cited, you would find that no biological treatment worked better than conventional treatments!
Don't forget about your basic plant pathology, too. It shouldn't be any suprise that sewage sludge, composts, and manures reduced dollar spot severity, since they contain N, which disrupts dollar spot and creates a healthier plant. If you actually read the studies cited, you'll find that no biological treatment reduced disease severity more than proper fertility and water management did.
BTW, I find it odd that I'm constantly reminded on this board how lawns are different than golf courses and that things from golf can't possibly be carried over to lawn maintenance. Then those same folks cite an article fro mGolf Course Maintenance magazine to prove their point about lawns. Intersting ...