The methods described in the interim testing protocol will have to be adapted to specific microbial agents, depending on the microbial pest control agents(MPCA) mode of action. Rickettsias, protozoans, bacteria, and viruses usually enter arthropods orally. Tests of these MPCAs should involve contamination of food. By contrast, fungi often infect arthropods through the integument. Testing of contact pathogenicity is recommended for fungal MPCAs. Microarthropods in the soil and litter would be sheltered from direct application of MPCAs but would become exposed to MPCAs entering the litter, either through contact with contaminated surfaces or through ingestion of contaminated material. Tests outlined here are designed to test effects of contact or ingestion at field rates and maximum hazard dose rates of exposure to MPCAs, on microarthropod survival, reproduction, and feeding rate.