Colonization of buried cotton stems by microarthropods

Initial colonization of cotton stems by microarthropods proceeded more rapidly while buried in soil under laboratory conditions (20–23°C) than while buried in the field during the winter months when soil temperatures ranged from 5–10°C in the study area in the San Joaquin Valley of California. While 15 species were found frequently in cotton stems held in the laboratory for 20 weeks, only seven species were found in field buried stems. Arthropods found under both conditions were a species of pyemotid mite; an astigmatid mite, Tyrophagus dimidiatus; two collembolans, Proisotoma minuta and Tullbergia sp.; and a sciarid fly larval stage, Bradysia impatiens. Even though the soils at teh field sites possessed a number of microarthropods in common, the stem colonization at each site was restricted to a single group which differed from each of the other sites. Microenvironments affect stem colonization patterns by microarthropods but microarthropods did not appear to have a significant influence on early cotton stem decomposition rates nor was there evidence that their activities reduced Verticillium microsclerotia populations.