We studied changes in populations of mites, nematodes, bacteria, and fungi in buried creosote bush litter treated with selected inhibitors. Elimination of microarthropods (primarily tydeid mites) resulted in increased numbers of bacteriophagic nematodes and reduction in numbers of bacteria; elimination of both nematodes and microarthropods resulted in increased numbers of bacteria compared to untreated controls. Fungal grazing mites, Pyemotidae, and funivourous nematodes, Aphelenchus sp., increased in numbers between days 25 and 30, reducing the fungi on untreated leaves but not on stems and petioles, while mean length of fungal hyphae increased in insecticide-treated leaves. Elimination of mites resulted in a 40% reduction in decomposition suggesting that in a desert, tydeid mites affect decomposition of buried litter by regulating the population size of the bacterial grazers, cephalobid nematodes.