Volatile organic compounds (VOCs), are gaseous metabolites that have varying effects, including inhibiting the growth of competing microbes. Two agricultural examples of using VOC-producing microbes are to inhibit the growth of plant pathogens or nitrifying microbes. Preliminary work has identified six bacterial strains that inhibit the growth of the fungal plant pathogen Sclerotinia, however the mechanism remains unknown. Nitrifiers present a problem for agriculture because their use of stable soil nitrogen for energy production causes that nitrogen to become volatile, allowing for nitrogen leaching, leading to imbalance of soil nutrients for plants and for pollution from runoff. The objective of my honors thesis is to test for VOC-dependent growth inhibition of the fungal pathogen Sclerotinia and the nitrifying bacteria, Nitrosopera multiformis. I will use a high-throughput 24-well plate system to screen for VOC-dependent growth inhibition from six bacterial isolates, Pseudomonas sp., two Bacillus sp., Variovorax paradoxus, Paenibacillus polymyxa, and Sphingobacterium kitahiroshimense. I placed 1 mL of agar in each well of 2 24-well plates; plate 1, the responders, is inoculated with Sclerotinia, or N. multiformis, plate 2, the producer, is randomly inoculated with 2 isolates over 6 wells, with another 12 wells left blank as controls. We will place a gasket with holes between the two 24-well plates that are stacked open faced against one another. This creates airtight cells to allow VOCs from producing bacterial isolates to inhibit the responders. After 14 days, we will take a picture of the responder plate, and then measure the surface area of the responders, as a measurement of growth. This is compared to responders that received no producer microbes. We expect that the effects of producer VOCs on the fungal pathogen and nitrifying bacteria will vary in response by producer. This research aims to determine any role that VOCs from VOC-producing soil bacteria may have in changing the growth of Sclerotinia and nitrifying microbes. Assessing the form of which inhibition occurs can inform application of microbes to aid against harmful effects of other microbes, in place of using current methods that could be harmful or introduce unwanted minerals into agricultural land.