Background: Metam potassium (metam-K) is a soil fumigant widely used to control plant pathogens, nematodes, and weeds in Florida plasticulture production. The objective of the study was to determine the efficacy of metam-K against Fusarium oxysporum, Macrophomina phaseolina, Meloidogyne javanica, and seven important weed species under controlled conditions. The optimal rates generated in this study provide insight into the efficacy of metam-K for field application.
Results: F. oxysporum and M. phaseolina were similarly sensitive toward metam-K with a 90% effective concentration (EC90 ) of 478 and 493 μmol kg-1 soil, respectively. Meloidogyne javanica was the most sensitive pest with an EC90 of 25 μmol kg-1 which is similar to previous studies. Chenopodium album was the most sensitive weed seed with an EC90 of 260 μmol kg-1 . Geranium carolinianum and Medicago lupulina were the least sensitive weed species with EC90 values of 786 and 567 μmol kg-1 , respectively.
Conclusion: It is apparent from these results that metam-K can effectively control important pests in Florida plasticulture production systems with the correct application rate and adequate exposure of pest to the fumigant.
Keywords: Metam potassium; microcosm assay; soil fumigation; soil-borne diseases; weed seeds.
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