No abstract

Alkyl aryl esters, dialkyl esters and diaryl esters of N-methyl-N-phenylphosphoramidic acid were synthesized and tested for cross-resistance and joint action with phosphorothiolate (PTL) fungicides using rice blast fungi, Pyricularia oryzae. Negative correlation in crossresistance was found between PTL fungicides and most of the amidates. Synergism in the fungicidal action was also found between them for wild types of the fungi, when tested by crossing filter paper strips impregnated with fungicides on agar plates inoculated uniformly with the test fungi.

Organophosphorus compounds, N-methylcarbamates, amide compounds, alcohols,phenols and other compounds were tested for joint action with phosphorothiolate (PTL)fungicides by crossing the paper strips impregnated with the test chemicals on agar plate uniformly seeded with rice blast fungus.Antagonism was found for phosphoramidothionate herbicide (amiprophos) and phosphorothiolothionate having carboxy ester structure (malathion and phenthoate).