OUTBREAKS OF VERTICILLIUM WILT ON ALMOND AND PATHOGENIC VARIATIONS AMONG ISOLATES OF V. DAHLIAE

Attacks of Verticillium dahlae Kleb. on Almond [Prunus dulcis (Mill.) D. A. Webb] were observed in southern Italy.
The symptoms of disease include: wilting of twigs, yellowing of leaves, early defoliation, vascular discoloration and death of the whole plant.
Six isolates of V. dahliae originating from Almond, Tomato, Peach, Apricot, Cherry and Olive were inoculated on Almond (cvs ‘Don Carlo’ and ‘Filippo Ceo’), Peach [Prunus persica (L.) Batsch], the rootstock Almond x Peach ‘GF 677’, Apricot (P. armeniaca L.), Cherry (P. avium L.), Plum (P. domestica L.), Olive (Olea europea L.), Tomato (Lycopersicon esculentum Mill.) and Eggplant (Solanum melongena L.). Tests on Tomato and Eggplant were carried out in the greenhouse at 24±2°C. Plants were inoculated by dipping the roots in a fungal suspension (3.3 x 10⁷ conidia/ml H₂O) of each isolate of the fungus.
Arboreous plant species were tested in the field: two-year-old plants were inoculated by introducing a drop of fungal suspension (2.6 x 10⁷ conidia/ml H₂O) into a small transverse cut made with a scalpel on the basal part of the main stem.

‘Don Carlo’ almond and the ‘GF 677’ rootstock were highly susceptible to all isolates, whereas ‘Filippo Ceo’ almond was somewhat less susceptible.
In general, the isolates of V. dahliae showed variable degrees of polyphagy and pathogenicity on the herbaceous and arboreous plants tested.
The cherry isolate was weakly aggressive on all plant species.
The isolate from Olive was highly pathogenic on Olive and moderately aggressive on the other plants, but did not affect Tomato.
The remaining isolates of V. dahliae were aggressive on all tested plant species.

I International Congress on Almond

N. Luisi, F. Ciccarese, G. Sicoli, M. Amenduni

https://doi.org/10.17660/ActaHortic.1994.373.41