This invention relates to certain novel
2-alkynyl-6-pyridin-2-yl-pyridazinones,
2-alkynyl-6-pyridin-2-yl-dihydropyridazinones,
2-alkynyl-6-pyrimidin-2-yl-pyridazinones and
2-alkynyl-6-pyrimidin-2-yl-dihydropyridazinones and to the use of these
compounds for control of fungal pathogens of plants and mammals.