Sterol Inhibiting fungicides

Hickey, K.D., and Yoder, K.S. 1981. Field Performance of sterol-inhibiting fungicides against apple powdery mildew in the mid-Atlantic apple growing region. Plant Dis. 65 1002-1006. 

Schwabe, W.F.S., Jones, A.L., and Jonker, J.P. 1984. Greenhouse evaluation of the curative and protective action of sterol-inhibiting fungicides against apple scab. Phytopathology 74 249-252. 

Yoder, K.S., and Hickey, K.D. 1981. Sterol-inhibiting fungicides for control of certain diseases of apple in the Cumberland- Shenandoah region. Plant Dis. 65 998-1001. 

Siegel, M. R. 1981. Sterol-inhibiting fungicides Effects on sterol biosynthesis and sites of action. Plant Disease 65 986-989. 

Ortho Spotkss. [ vton] Diniconazole systenric, sterol-inhibiting fungicide for use on peanuts, qqdes, grq)es, small grains, etc. 

Bateman, G.L., Nicholls, P.H., Chamberlain, K. (1990) The effectiveness of eleven sterol biosynthesis-inhibiting fungicides against the take-all fungus (Gaeumannomyces gramminis, var. tritici) in relation to their physical properties. Pest. Sci. 29, 109-122. Baulch, D.L., Cox, R.A., Hampson, R.F., Jr., Kerr, J.A., Troe, J., Watson, R.T. (1984) Evaluated kinetic and photochemical data for atmospheric chemistry (Supplement II). J. Phys. Chem. Ref. Data 13, 1255-1380. 

Imibenconazole is a triazole fungicide exhibiting direct cell membrane destruction as well as sterol biosynthesis inhibition for controlling major diseases of fruits, vegetables, cereals, ornamentals and turf. 

Although termed "SI" or "EBI" compounds, the latter referring to ergosterol biosythesis inhibitors, these compounds do not all inhibit ergosterol biosynthesis at the same metabolic site (Fig. 2). For instance, the fungicide tridemorph, unlike most EBI compounds, does not inhibit demethylation at C-14 but rather it apparently prevents the A A isomerization resulting in the accumulation of A containing sterols in treated cells (3). 

Morpholines such as tridemorph (9.112) attack sterol biosynthesis via A -reductase enzyme inhibition and are valuable agricultural fungicides. 

In research for new fungicides and antimycotics, one has to look for a concept for pathogen-specific inhibitors. This means that inhibition of sterol synthesis should not take place at any common step the aim is to only inhibit pathogen-specific steps in biosynthesis. The reason for this is to minimize the risk of human toxicity. If one compares the biosynthesis of mammalian cholesterol to that of ergosterol, the main sterol of pathogenic fungi, it becomes obvious that there are at least four pathogen-specific steps to be inhibited. 

---