Authors
Alberto
Bianchi
,
Dipartimento di Biologia Evolutiva e Funzionale, viale delle Scienze, 43100 Parma
;
Alessandra
Zambonelli
and
Aldo Zechini
D'Aulerio
,
Dipartimento di Protezione e Valorizzazione Agroalimentare, via Filippo Re 8, 40126 Bologna
; and
Franco
Bellesia
,
Dipartimento di Chimica, via Campi 183, 41100 Modena
ABSTRACT
A study was made of the effects of garlic on the development of mycelium in the following phytopathogenic fungi: Fusarium solani (Mart.) Sacc., Rhizoctonia solani Kühn, Pythium ultimum Trow var. ultimum, and Colletotrichum lindemuthianum (Sacc. and Magnus) Briosi and Cav. A suspension of micronized garlic powder, which has volatile organic compounds mainly consisting of linear chain aldehydes, allyl sulfides and disulfides, was used for the trials. Mycelial development of the fungi was strongly inhibited at the maximum concentration of the aqueous extract tested (100 ml/liter); however only the growth of P. ultimum var. ultimum was entirely blocked. Transmission and scanning electron microscopy revealed cytomorphological alterations of the hyphae treated with garlic. R. solani and C. lindemuthianum hyphae appeared especially collapsed, while those of F. solani were less damaged, although thinner than the control hyphae. A general increase in vacuolization was also observed, with consequent reduction in the cytoplasm of the treated fungal cells. R. solani also revealed a thickening of the cell wall, whereas C. lindemuthianum revealed a singular accumulation of osmiophil bodies immediately under the cell membrane.
