Efficacy of metam potassium on Fusarium oxysporum, Macrophomina phaseolina, Meloidogyne javanica, and seven weed species in microcosm experiments.

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 (EC ) of 478 and 493 μmol kg soil, respectively. Meloidogyne javanica was the most sensitive pest with an EC of 25 μmol kg which is similar to previous studies. Chenopodium album was the most sensitive weed seed with an EC of 260 μmol kg . Geranium carolinianum and Medicago lupulina were the least sensitive weed species with EC values of 786 and 567 μmol kg , 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.