Characterization of tomato leaf mould pathogen, Passalora fulva, in Croatia

Abstract

Leaf mould (Passalora fulva) has emerged as an important disease of greenhouse-growing tomato crops in Croatia during the last decade. In order to establish sustainable control measures, the presence of P. fulva races was investigated, in vitro sensitivity of the fungus to several fungicidal products was tested, and susceptibility of some old tomato varieties was checked. Seventeen isolates were collected from different parts of Croatia and inoculated on tomato cv. ‘Moneymaker’ differentials with different resistance genes (Cf-2, Cf-4, Cf-5 and Cf-9) or without resistance genes (Cf-0). Based on symptoms appearance assessment, 11 isolates were determined as P. fulva race 2, two isolates as race 5, one isolate as race 2.5 and three isolate as race 0. Sequence analysis of the Avr2 gene of five P. fulva race 2 isolates showed and insertion of adenine at 117_119 bp compared to the reference Avr2 wild-type gene retrieved from GenBank®, which leads to amino acid change from Tyrosine to Valine (p. Tyr41ValfsX1) in Avr2 protein. Pathogenicity tests with a P. fulva race 2 isolate on seven old tomato varieties lead to the development of leaf mould symptoms on four of seven varieties. Sensitivity of a selected P. fulva race 2 isolate was examined on agar plates amended with four fungicides products which were authorized in Croatia at that time for control different diseases on tomato. According to the results, Signum® was significantly and constantly the most effective product across all assessment periods.