Natural products as sources of new fungicides: synthesis and antifungal activity of zopfiellin analogues.

The synthesis of a series of cyclooctadiene anhydrides, analogues of the natural compound zopfiellin, was performed to assay their in vitro and in vivo antifungal activity on a set of plant pathogenic fungi. Most of the synthesized compounds possessed a broad spectrum of activity. In particular, the anhydrides 2 and 5a were very effective against the Oomycete diseases such as Phytophthora infestans and Pythium ultimum, reaching a level of activity well comparable with that of commercial fungicides in use.

Synthesis and antifungal activity of 2-hydroxy-4,5-methylenedioxyaryl ketones as analogues of kakuol.

In a study aiming to determine the structural elements essential to the antifungal activity of kakuol, we synthesized a series of 2-hydroxy-4,5-methylenedioxyaryl ketones, and we assayed their in vitro antifungal activity. The most sensitive target organisms to the action of these class of compounds were Phytophthora infestans, Phytium ultimum, Cercospora beticola, Cladosporium cucumerinum, and Rhizoctonia solani. Most of the analogs showed a remarkable in vitro activity, and some of them appeared significantly more effective than the natural product.

Synthesis and antifungal activity of a series of N-substituted [2-(2,4-dichlorophenyl)-3-(1,2,4-triazol-1-yl)]propylamines.

A series of N-mono- or N, N-disubstituted [2-(2,4-dichlorophenyl-3-(1,2,4-triazol-1-yl)]propylamines and N-[2-(2,4-dichlorophenyl-3-(1,2,4-triazol-1-yl)propyl]amides were synthesized and tested for their fungicidal activity in vitro and in vivo against a group of plant pathogenic fungi. Some compounds exhibited a fairly good in vitro activity. The replacement of the ether group of tetraconazole with a secondary or tertiary amino group leads to compounds that maintain the antifungal activity on several phytopathogenic fungi, provided that the substituents are not too bulky or lipophilic.

Histological studies on the mycoparasitism of Cladosporium tenuissimum on urediniospores of Uromyces appendiculatus.

Interactions between the mycoparasite Cladosporium tenuissimum and the bean rust Uromyces appendiculatus were studied through light and electron microscopy in vitro at the host-parasite interface. Urediniospore germination decreased on contact with ungerminated C. tenuissimum conidia, possibly due to antibiosis mechanisms.

Characterization of field-isolates and derived DMI-resistant strains of Cercospora beticola.

Cercospora beticola strains with laboratory induced resistance to tetraconazole were compared with their parental WT sensitive strains to evaluate the effects of resistance on fitness and assess whether any change in the sterol biosynthetic pathway was associated to the reduced fungicide sensitivity. In vitro growth rate on agar media and pathogenicity were found to be negatively affected by resistance. The main functional sterols in C.