DIMETHOMORPH ACITIVITY ON DIFFERENT OOMYCETE SPECIES OF ECONOMIC AND VETERINARY INTEREST

The class Oomycota comprises species that are pathogenic to plants and animals, including humans, and are able to cause severe economic losses in agriculture and aquaculture industry worldwide. Phytophthora infestans causes losses in potato and tomato crops for more than 6 billion per year, as well as damage to ecosystems; Plasmopara viticola is responsible for downy mildew, which is one of the most damaging grapevine diseases. The genus Phytium, includes species that are pathogenic to both plants and animals, particularly, Phytium insidiosum has been reported to cause disease in humans and in other mammals. Oomycetes of the order Saprolegniales are widely distributed in freshwater environments, causing infections in different taxa of aquatic animals. Among these, members of the genus Saprolegnia represent a severe problem in freshwater fish farms, where production losses from 10 to 50% are reported. Despite the wide distribution and the impact of oomycetes on economic activities and on animal health, there are no effective available molecules against these agents. Following the current classification of malachite green and formalin among carcinogens, there are limited possibilities to control oomycete infections in aquaculture. The aim of this work was to test in vitro the activity of dimethomorph, a fungicide used in agriculture to control oomycete infections, on different species of Saprolegnia and Pythium isolated from fish and aquatic environment. Although no complete inhibition was observed at tested concentrations (0.1; 1; 5; 10; 50; 100 mg/L) mycelial growth was slowed down at highest concentrations. Furthermore our results suggest a different susceptibility of dimethomorph on the tested oomycete species.