Xanthium italicum, Xanthium strumarium and Arctium lappa as new hosts for Diaporthe helianthi

Abstract

Sunflower (Helianthus annuus) stem canker caused by Diaporthe helianthi is one of the most important sunflower diseases in Croatia. Until recently, sunflower was the only known host for D. helianthi. In our research carried out in the area of Eastern Croatia, isolates of Diaporthe/Phomospis were collected from Xanthium italicum, X. strumarium and Arctium lappa. Using morphological, cultural and molecular ITS rDNA data, isolates from these weeds were identified as D. helianthi. The following isolates were used in the pathogenicity test: one isolate originated from sunflower (Su5/04), three from X. italicum (Xa2, Xa3 and Xa5), two from X. strumarium (Xa9 and Xa12), one from Xanthium sp. (Xa13) and one from A. lappa (Ar3). According to the results, it was determined that isolate Xa5 (originated from X. italicum) was the most pathogenic to sunflower stems. The average length of the lesion was 11.3 cm. The lowest level of pathogenicity was found in Xa9 (isolated from X. strumarium). The length of the lesion was 0.1 cm.

Green and brown bridges between weeds and crops reveal novel <I>Diaporthe</I> species in Australia

“…We suggest that the ‘brown bridge’ of weed residues plays as significant a role in aiding the survival of Diaporthe species. This is comparable to the ‘green bridge’ of alternative live weed hosts, such as those that facilitate survival of pathogenic Diaporthe species between cropping phases ( Mihaljcevic & Muntañola-Cvetković 1985 , Roy et al 1997 , Li et al 2001 , 2010 , Vrandečić et al 2010 ).…”

“…Phomopsis helianthi ) on sunflower in the former Yugoslavia (now Serbia), Mihaljcevic & Muntañola-Cvetković (1985) recovered Diaporthe species from 15 plant species, including the weeds Xanthium italicum and X. strumarium . Subsequent studies by Vrandečić et al (2010) confirmed Arctium lappa , X. italicum and X. strumarium as weed hosts for D . helianthi.…”

Stem cankers on sunflower (Helianthus annuus) in Australia reveal a complex of pathogenic Diaporthe (Phomopsis) species

“…The phylogenetic analysis of the ITS dataset included 31 isolates of D. helianthi sourced from five publications (Says-Lesage et al 2002, van Niekerk et al 2005, Bernardi-Wenzel et al 2010, Santos et al 2010, Vrandecic et al 2010) and formed three distinct clades (Fig. 1).…”

“…1). Diaporthe helianthi has also been recorded from hosts other than sunflower in Croatia (Vrandecic et al 2010), which was part of the former Yugoslavia. All records of D. helianthi from hosts other than sunflower, without comparison to sequence data from ex-type cultures, should be treated with caution (e.g.…”

Two new species of Diaporthe (Diaporthaceae, Diaporthales) in China

“…In previous studies, Smilax glabra and Xanthium strumarium have been reported as hosts of Diaporthe (Vrandecic et al 2007(Vrandecic et al , 2010Gao et al 2013;Thompson et al 2018). D. eres (= D. mahothocarpi) and D. lithocarpi were identified as the cause agents of leaf spot disease based on morphology and phylogenetics on S. glabra in China (Gao et al 2013).…”