The black pepper (Piper nigrum L.) is one of the most popular peppers in the world. Nonetheless, there are several limitations on cultivation, resulting in reduced production or a complete loss of the crop. The major disease affecting this crop is fusarium root rot caused by Fusarium solani f. sp. piperis, which is responsible for decimating whole crops in Brazil, with losses reaching millions of dollars per year. So far, there is no effective control measure against this fungus and no cultivars resistant to it. In this study, in vitro effects of different products on colony growth was evaluated. Carbendazim, chitosan, silicon, and phosphate were tested against F.solani f. sp. piperis isolates CML-2466, CML-2353, E-637, and E-596. Chitosan and silicon did not inhibit mycelial growth of any of the isolates, while phosphite inhibited mycelial growth by 100%. Carbendazim was found to be fungitoxic for isolates CML-2353 and E-596 and fungistatic for CML-2466 and E-637, inhibiting the mycelial growth of these isolates by 60 and 80%, respectively. There were no dose effects of the products tested.