Lichens are composite organisms comprising of a photobiont and a mycobiont. Studies have shown that extracts and secondary metabolites from lichens exhibit various bioactivities. The present study evaluates antifungal potential of crude methanolic extract of two corticolous Parmotrema species viz. Parmotrema tinctorum (Delise ex Nyl.) Hale and Parmotrema cristiferum (Taylor) Hale against a panel of fungi isolated from seeds of maize and groundnut. Extraction of powdered lichens was carried out by maceration process using methanol. Antifungal activity was evaluated by poisoned food technique. Both extracts were effective in causing dose dependent inhibition of radial growth of test fungi in poisoned plates. Among lichens, marked inhibitory activity was shown by P. cristiferum. At 1mg/ml concentration, P. cristiferum displayed an inhibition of >50% of all test fungi. The antifungal activity of two Parmotrema species against seed mycoflora could be ascribed to the presence of secondary metabolites in extracts.