potentiator has been discovered to enhance the activity of the succinate dehydrogenase such that the amount of the succinate dehydrogenase inhibitor need to effectively treat a microbial substance can be reduced substantially the compositions may be used as additives for paints and coatings and protecting crops seeds wallboard metal working fluids wood from mold fungi and other microbes application_number US 201615394020 A description it has now been surprisingly found certain compounds called herein u201c potentiators u201d can effectively increase the activity of active substances which inhibit succinate dehydrogenase in the mitochondrial respiration chain as a result the combination of the succinate dehydrogenase inhibitor with an effective amount of a potentiator has advantages which will be described herein in conjunction with the present invention all active substances which inhibit succinate dehydrogenase in the mitochondrial respiration chain can be used in a particular embodiment of the present invention the succinate dehydrogenase inhibitor is a carboxamide compound suitable carboxamide compounds include carboxanilides carboxylic morpholides benzoic acid amides and other carboxamides exemplary carboxanilides include for example benalaxyl benalaxyl m benodanil bixafen boscalid carboxin fenfuram fenhexamid flutolanil fluxapyroxad furametpyr isopyrazam isotianil kiralaxyl mepronil metalaxyl metalaxyl m mefenoxam ofurace oxadixyl oxy carboxin penflufen penthiopyrad sedaxane tecloftalam thifluzamide tiadinil 2 amino 4 methyl thiazole 5 carboxanilide n 4 u2032 trifluoromethylthiobiphenyl 2 yl 3 difluoromethyl 1 methyl 1h pyrazole 4 carboxamide and n 2 1 3 3 trimethyl butyl phenyl 1 3 dimethyl 5 fluoro 1h pyrazole 4 carboxamide exemplary benzoic acid amides.