Characterization and pathogenicity assessment of Plectosphaerella species associated with stunting disease on tomato and pepper crops in Italy

This study follows a survey carried out in 2012 and 2013 on tomato and pepper crops in the Foggia province (southern Italy), for morphological, molecular and pathogenicity analyses of Plectosphaerella fungi. The Plectosphaerella genus includes several species that are pathogens of horticultural plants. The survey identified tomato and pepper crops that showed abundant wilt, leaf yellowing, and discolouration and necrosis of roots, plus collar and stem symptoms. Different fungi including Plectosphaerella spp. were isolated from tissues with and without symptoms. Subsequent molecular and morphological studies identified first records of P.citrulli infecting tomato and pepper, and P.pauciseptata and P.ramiseptata infecting pepper. Pathogenicity testing confirmed that most isolated species of Plectosphaerella caused symptoms on tomato and pepper, with P.ramiseptata the most aggressive. On the basis of these data, it is considered that Plectosphaerella species may cause stunting disease in tomato and pepper.