Biological assessment of fungicides in vitro

Abstract

During the testing of plant protection methods on the fields we need a longer period of time, large expenditure of material and labor. It’s not always possible to evaluate the efficiency of chemical drugs to one definite type of pathogen. On the naturally infected fields the plants are infected by some kinds of fungi, that produce the same symptoms of the disease. Thus it is essential to study the efficiency of fungicides to some kinds of phyto pathogens in the artificial conditions or to use laboratory methods with the application of pure cultures of fungi. One of these methods is Plate Count Agar (PCA) (also called Standard Methods Agar (SMA)). It has been established that this method can be used for biological assessment of fungicides (in vitro) for the fungi Fusarium, and also for other species which grow in the artificial conditions. The method consists in the following: in the experimental variants, a suspension of conidia of the fungus and a solution of the chemical drug are applied to the agar plate, in the control variant sterile water is applied instead of the fungicide. After the process of incubation in the thermostat, a number of formed fungal colonies and their diameter are assessed. The application of Plate Count Agar (PCA) (also called Standard Methods Agar (SMA)) gave the opportunity to reveal the most efficient (92.2-100.0%) for the fungi Fusarium semitectum, F. tricinctum and Bipolaris sorokiniana chemical drugs ‘Kinto Duo’, ‘Vitaros’, ‘Vintsit’, ‘Maksim’, ‘Vial TT’ and ‘Maksim ekstrim’. The fungicides ‘Kolfugo super’ and ‘Falkon’ showed their largest inhibitory effect (with the efficiency of 97.3-98.6%) for the fungus Fusarium graminearum.