Baiting samples of muck soil from Quebec with sclerotia of Sclerotinia sclerotiorum revealed that Trichoderma, Gliocladium, Penicillium, Sporidesmium, Rhizopus, Myxomycetes, Bradysia (dark-winged fungus gnat), and Onychiurus sp. (springtails, Order Collembola) were present in the soils. The number of larvae of Bradysia was positively correlated with low soil pH, high levels of organic matter, and high levels of nitrate in the soil. There was no correlation between fungi or Onychiuris sp. recovered and any of the above soil parameters. In in vitro tests, sclerotia damaged by the feeding of the larvae of Bradysia had levels of mycelial germination of 0-30%, whereas undamaged sclerotia germinated at a rate of 95%. When sclerotia were buried at different depths in soil, and larvae or adults of Bradysia were placed on the soil surface, predation of sclerotia was greatest in the top 2 cm of soil. The larvae were recovered from as deep as 9 cm in the soil.