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 widely used soil fumigant to control plant pathogens, nematodes, and weeds in Florida plasticulture production. The objective of the project was to determine the efficacy of metam-K against Fusarium oxysporum, Macrophomina phaseolina, Meloidogyne javanica, and seven important weed species in controlled conditions. The optimal rates generated in this study will provide insight on the efficacy of metam-K for field application.

Results: Fusarium oxysporum and M. phaseolina were similarly sensitive toward metam-K with an 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 correct application rate and adequate exposure of pest to the fumigant. This article is protected by copyright. All rights reserved.

Keywords: Metam potassium; microcosm assay; soil fumigation; soil-borne diseases; weed seeds.