New foci of strawberry Fusarium wilt in Huelva (Spain) and susceptibility of the most commonly used cultivars

- Confirmed the appearance of new 19 foci of strawberry Fusarium wilt in Huelva.
- Cultivars have different Fusarium wilt susceptibility to Spanish or Japanese inocula.
- Five cultivars show low susceptibility to strawberry Fusarium wilt in Huelva.

Strawberry Fusarium wilt is becoming an important disease after methyl bromide banning. In southwestern Spain, this disease was previously detected in a soilless culture system and several years later only one isolation was reported from plant cultivated in soil. This study reports the appearance of new foci of strawberry Fusarium wilt in plants cultivated on soils and evaluates the susceptibility of nine of the most commonly grown cultivars in this zone. Fungal isolates were obtained from diseased strawberry plants in the nineteen new foci showing an increase of incidence and geographic range of this disease. These isolates were morphologically and molecularly characterized as Fusarium oxysporum. Fofra amplicons were not obtained and only eight isolates amplified for Fusarium transcription factor 1. Pathogenicity of six selected isolates as well as a Fusarium oxysporum f. sp. fragariae culture from Japan were tested using by inoculating cultivar 'Splendor'. All the Spanish isolates were found to be pathogenic. As a follow-up study, nine strawberry cultivars were inoculated with the Japanese isolate and a mixture of three Spanish isolates. The least susceptible cultivars to the Spanish isolates were 'Rociera FNM', 'San Andreas', 'Camarosa', 'Sabrina' and 'Sabrosa Candonga'. Cultivar susceptibility was different with respect to Japanese isolate.