** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** CURRENT PROBLEM: IN THE TROPICS AND SUBTROPICS, FARMS ARE AFFECTED BY INCREASING INPUT COSTS, HIGH PEST LOADS, AND NUTRIENT-POOR SOILS. THE USE OF CERTAIN COVER CROPS CAN SERVE AS A LOW-COST INTERVENTION TO IMPROVE SOIL FERTILITY, AS THEY CAN FORM SYMBIOTIC ASSOCIATIONS WITH NITROGEN FIXING SOIL BACTERIA. THUS, MULCHING THESE COVER CROPS HAS BEEN SHOWN TO IMPROVE SOIL FERTILITY, LEADING TO HIGHER CROP YIELDS. PLANTS IN THE GENUSCROTALARIAHAVE THE ADDED BENEFIT OF PRODUCING ANTI-NEMATODE ALKALOIDS, WHICH CAN SIGNIFICANTLY REDUCE THE NEMATODE LOAD IN THE SOIL, FURTHER PROTECTING CROPS AND IMPROVING YIELDS. THESE ALKALOIDS ARE ONLY PRODUCED IN PLANTS INFECTED WITH CERTAIN MICROBES (STERILE PLANTS DO NOT PRODUCE THEM), SUGGESTING AN INTIMATE RELATIONSHIP BETWEEN MICROBIAL INFECTION AND ALKALOID PRODUCTION.PLANT-FEEDING PATHOGENIC NEMATODES ARE A MAJOR AGRICULTURAL PEST GLOBALLY AND ARE RESPONSIBLE FOR APPROXIMATELY USD $215 BILLION IN ANNUAL LOSSES FOR ONLY THE TOP 20 LIFE-SUSTAINING CROPS. THIS FIGURE IS LIKELY AN UNDERESTIMATE DUE TO THE CRYPTIC NATURE OF PATHOGENIC NEMATODES AND LIKELIHOOD THAT NEMATODE ATTACK MAY BE CONFUSED WITH FUNGAL DAMAGE, WATER STRESS, OR OTHER PHYSIOLOGICAL ISSUES.THUS, THE DEVELOPMENT OF MICROBIAL INOCULANTS FOR GREEN MANURE CROPS HAS THE POTENTIAL TO SIGNIFICANTLY BOOST PLANT HEALTH THROUGH IMPROVED SOIL FERTILITY. NEMATODES CONTRIBUTE TO THE LOSS OF ECONOMICALLY IMPORTANT CROPS SUCH AS COFFEE, PINEAPPLE, AND SUGARCANE IN HAWAI'I SPECIFICALLY, IN ADDITION TO THE DAMAGE THEY CAUSE TO ORNAMENTALS.GOALS AND METHODS: THE GOAL OF THIS RESEARCH IS TO IDENTIFY AND DEVELOP SPECIFIC MICROBIAL STRAINS FROM NATURAL POPULATIONS OFCROTALARIAACROSS HAWAI'I. PLANTS AND THEIR ASSOCIATED MICROBES WILL BE COLLECTED FROM THESE POPULATIONS AND USED TO DEVELOP INOCULANTS WHICH WILL BE EXPERIMENTALLY TESTED IN ORDER TO IDENTIFY SPECIFIC STRAINS THAT OPTIMIZE PLANT HEALTH, BIOMASS, NITROGEN PRODUCTION, AND ALKALOID CONTENT. FURTHER, WE WILL EXPERIMENTALLY TEST HOW DIFFERENT PHYTOCHEMICAL MIXTURES (DIFFERENT COMBINATIONS OF ALKALOIDS) CAN AFFECT NEMATODE POPULATIONS IN FIELD AND LAB CONDITIONS. TAKEN TOGETHER, THE RESULTS FROM THESE OBJECTIVES WILL IMPROVE THE UTILITY OF A LOW-COST GREEN MANURE PLANT THAT CAN GIVE GROWERS A 2-FOR-1 DEAL: IMPROVED SOIL FERTILITY AND EFFECTIVE NEMATODE CONTROL.