The later-synthesized strobilurins, however showed different levels of activity against different
plant diseases (Heaney and Knight, 1994). Kresoximmethyl
was not only very effective in controlling powdery
mildew and apple scab, but also showed moderate
activity against many Oomycete diseases, including
grapevine downy mildew (Brunelli et al., 1996). In contrast,
kresoxim-methyl was ineffective in the control of
a number of Basidiomycete diseases, such as wheat
and barley brown rusts. Azoxystrobin which shows a
strong preventative activity through inhibition of fungal
germination, has a wide antifungal spectrum
against all four taxonomic groups of fungi, and thus
has been used commercially as one of the worlds biggest-selling
fungicides (Bartlett et al., 2002). Pyraclostrobin
was also developed as a broad-spectrum
fungicide for use on a wide range of crops, especially
cereals (Bartlett et al., 2002). The strobilurin fungicides
are evaluated to be the most important class of microbial
fungicides to date.