【正文】
hway ?AcibenzolarSmethyl阿拉酸式苯S甲基 ?Probenazole噻菌靈 35 11 Multisite contact activity ?(1) inanic: copper, sulphur ?(2) dithiocarbamate and relatives: ? mancozeb代森錳鋅, thiram福美雙 ?(3) chloronitriles氯化氰類 : ?chlorothalonil百菌清 ?(4) sulfamides 硫酰胺類 ? Dichlofluanid抑菌靈 36 11 Multisite contact activity ?(4) guanidines胍 ?(5) triazines三嗪類 ? Anilazine敵菌靈 ?(6) quinones醌類 ?Dithianon二噻農(nóng) 37 Biological mode of action Fungicidal action can be expressed in one of two physically visible ways. ?Inhibition of spore germination. ?Inhibition of fungus growth. 38 Physiological mode of action What happens at the cellular level to cause the visible effects on spore germination and fungal growth? 39 Why is it important to be familiar with the physiological mode of action of a fungicide ? ? For resistance management and preservation of fungicide effectiveness. 40 The physiological mode of action ?Fungicides are metabolic inhibitors and their modes of action can be classified into four broad groups. ?Inhibitors of electron transport chain. ?Inhibitors of enzymes. ?Inhibitors of nucleic acid metabolism and protein synthesis. ?Inhibitors of sterol synthesis. 41 Inhibition of electron transport chain (Respiration in mitochondria) ?Sulfur ?Disrupts electron transport along the cytochromes ?Strobilurins (azoxystrobin, kresoximmethyl, pyraclostrobin, trifloxystrobin) ?Inhibit mitochondrial respiration, blocking the cytochrome bc1 plex. 42 Inhibition of enzymes ? Copper –Nonspecific denaturation of proteins and enzymes. ? Dithiocarbamates (maneb(代森錳 ), manzate, dithane, etc) –Inactivate –SH groups in amino acids, proteins and enzymes. 43 Inhibition of enzymes ? Substituted aromatics (chlorothalonil, 百菌清 ) –Inactivate amino acids, proteins and enzymes by bining with amino and thiol groups. ? Organophosphonate (fosetylAl,三乙磷鋁 ) –Disrupts amino acid metabolism. 44 Inhibition of nucleic acid metabolism and protein synthesis ? Benzimidazoles (thiophanatemethyl) –Inhibit DNA synthesis (nuclear division). ? Phenylamides (mefenoxam精甲霜靈 ) –Inhibits RNA synthesis. ? Dicarboximides (iprodione, vinclozolin) –Inhibits DNA and RNA synthesis, cell division and cellular metabolism. 45 Inhibition of sterol synthesis (Inhibit demethylation of ergosterol) ? Ergosterol (麥角固醇 ) is the major sterol in most fungi. ? It is essential for membrane structure and function. 46 Sterol inhibiting fungicides ? Imidazoles (imazalil抑霉唑 ) ? Triazoles (propiconazol