In Vitro Effects of Film-Forming Polymers on the Growth and Morphology of Pyrenophora Avenae and Pyricularia Oryzae

Ethokem (Midkem Agrochemicals, Northampton, UK) and Bond (Newman Agrochemicals, Cambridge, UK) completely inhibited linear growth of Pyricularia oryzae at 1 and 2% concentrations of the compounds and strongly inhibited growth of Pyrenophora avenae in vitro. Vapor Gard (Miller Chemical & Fertilizer Corporation, Hannover, PA, USA) was less e€ective with relatively little inhibition of P. oryzae, but was a more e€ective inhibitor of P. avenae. All three compounds decreased cell lengths of both pathogens and increased cell diameters of P. avenae. Vapor Gard and Ethokem did not signi®cantly alter cell diameters of P. oryzae, but a highly signi®cant increase was observed with Bond. Gross changes in hyphal morphology were observed including swollen shortened cells, granulation of the cytoplasm, increased branching and collapsed empty cells. Ethokem and Bond decreased growth rate and inhibited biomass production of P. avenae.