The manual provides detailed procedures for EPA/AEERL's Level 1 terrestrial bioassays. (Some test methods designated for AEERL's Level 1 environmental assessment biological testing program are sufficiently new that little or no published literature is available describing specific application of the procedures.) The manual supplements the 'IERL-RTP Procedures Manual: Level 1 Environmental Assessment Biological Tests' (second edition, EPA-600/8-81-024, NTIS No. PB 82-228966) which provides the basic procedural steps. The protocols described in the manual are the same as those in the supplemented manual, but are expanded in those areas of methodology which involve culturing methods, materials and supplies, and specific scoring procedures. The three tests included in the manual are: (a) Plant Stress Ethylene Test, to assess the toxic effects of gaseous samples on plant foliage; (b) Root Elongation Test, to determine the toxic effects of liquid samples and aqueous leachates on seed germination and root elongation in a number of plant species; and (c) Insect Toxicity Test, to measure lethality and reproductive toxicity in Drosophila melanogaster.