Alternaria disease is one of the most widespread and economically damaging diseases of the Solanum lycopersicum L. tomato plant. Under the influence of the disease, productivity can decrease up to 78%, and in epiphytotia up to 100%. The disease infests the leaves, branches and fruits of the plant. This article presents the results of the studies carried out on the application of the fungicide Previkur Pro72,2% w.s.p.