A destructive disease was observed in August 1981 in a field of Cucumis sativus cv. Radar. Since then sporadic spots on leaves of the same cultivar were recorded in 1985, 1988 and 1993. The causal agent was identified in Bipolaris multiformis (Jooste) Alcorn. The fungus produces frequently irregular (mostly Y-shaped) conidia in culture but rarely on leaves. The pathogen germinates bipolarly in distilled water at 20-25 degrees C (95 and 90% respectively), and on leaves it produces appressoria; entry points are either stomata or the intact surface. Pathogenicity tests carried out on various cucurbitaceous plants showed symptom intensity decreasing with the following order: C. sativus cv. Radar and Ecballium elaterium > Brionia cretica subsp. dioica > Cucurbita pepo L. var. pommiformis and C. pepo var. patissonina f. radiata > C. moscata and Sechium edule. The other two tested cultivars of Cucumis sativus (Mezzo lungo Marketer and Corto per sottaceti) and C. pepo cv. Verde scuro di Milano showed sterile, very small necrotic dot. Control plants, Citrullus lanatus cv. Sugar baby, Cucumbis melo and Lagenaria ia siceraria showed no symptoms.
BIPOLARIS MULTIFORMIS (JOOSTE) ALCORN PATHOGENIC ON LEAVES OF CUCUMIS-SATIVUS IN ITALY
VANNACCI, GIOVANNI
1995-01-01
Abstract
A destructive disease was observed in August 1981 in a field of Cucumis sativus cv. Radar. Since then sporadic spots on leaves of the same cultivar were recorded in 1985, 1988 and 1993. The causal agent was identified in Bipolaris multiformis (Jooste) Alcorn. The fungus produces frequently irregular (mostly Y-shaped) conidia in culture but rarely on leaves. The pathogen germinates bipolarly in distilled water at 20-25 degrees C (95 and 90% respectively), and on leaves it produces appressoria; entry points are either stomata or the intact surface. Pathogenicity tests carried out on various cucurbitaceous plants showed symptom intensity decreasing with the following order: C. sativus cv. Radar and Ecballium elaterium > Brionia cretica subsp. dioica > Cucurbita pepo L. var. pommiformis and C. pepo var. patissonina f. radiata > C. moscata and Sechium edule. The other two tested cultivars of Cucumis sativus (Mezzo lungo Marketer and Corto per sottaceti) and C. pepo cv. Verde scuro di Milano showed sterile, very small necrotic dot. Control plants, Citrullus lanatus cv. Sugar baby, Cucumbis melo and Lagenaria ia siceraria showed no symptoms.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
