From Native Plants in Central Europe to Cultivated Crops Worldwide: The Emergence of Didymella bryoniae as a Cucurbit Pathogen

Abstract

Additional index words. Bryonia alba, Citrullus lanatus, Cucumis sativus, gummy stem blight, seed Abstract. Didymella bryoniae (Auersw.) Rehm [anamorph Phoma cucurbitacearum (Fr.) Sacc.], the plant pathogenic fungus that causes gummy stem blight and black rot on cucurbits, was first described in 1869 from Bryonia (bryony or wild hops) in central Europe. Today, this pathogen is found on six continents on at least 12 genera and 23 species of cucurbits. How did D. bryoniae progress from a pathogen of a native plant in central Europe to a worldwide threat to cucurbits cultivated in humid environments? Clues from the early discoveries of this fungus, its characteristics as a seedborne pathogen, and its broad adaptation to cucurbit hosts will provide some answers to this question.

Two Stagonosporopsis species identified as causal agents of gummy stem blight epidemics of gherkin cucumber (Cucumis sativus) in Karnataka, India

“…Ascospores can serve as the primary inoculum and are readily spread among fields by wind once released from fungal fruiting bodies after rain or heavy dew (Song et al 2004). Additionally, inoculum can persist in crop residues (Keinath 2008) and be transmitted through seed (Keinath 2011). To our knowledge, no studies have been conducted regarding the molecular identification of Stagonosporopsis species causing gummy stem blight in India or on the cause of gummy stem blight epidemics of gherkin.…”

Evolutionary history and variation in host range of three Stagonosporopsis species causing gummy stem blight of cucurbits

“…S. cucurbitacearum is a major pathogen of cucurbits worldwide and occurs everywhere they are grown, infecting at least 12 genera and 23 species of the Cucurbitaceae, including watermelon (Citrullus lanatus), cucumber (Cucumis sativus), cantaloupe and muskmelon (Cucumis melo), squashes (Cucurbita pepo), and gourds (Cucurbita spp. ; Keinath 2011). It was first reported as Sphaeria cucurbitacearum on a cucurbit in Europe in 1823 by E. Fries, then in 1869 by Fuckel and Auerswald on Bryonia, a wild cucurbit host (Keinath 2011).…”

“…; Keinath 2011). It was first reported as Sphaeria cucurbitacearum on a cucurbit in Europe in 1823 by E. Fries, then in 1869 by Fuckel and Auerswald on Bryonia, a wild cucurbit host (Keinath 2011). It was later reported in 1891 in France, Italy, and the United States on cucumber and watermelon (Chester 1891;Chiu & Walker 1949;Farr & Rossman 2010); however, the geographic origin of S. cucurbitacearum is unknown.…”

Emerging multi-pathogen disease caused by Didymella bryoniae and pathogenic bacteria on Styrian oil pumpkin

“…Rehm (anamorph Phoma cucurbitacearum) was identified. This fungus was first reported in Europe in 1869 from Bryonia (wild hops) and today it is found on six continents as pathogen on a broad range of Cucurbitaceae (Chiu and Walker 1949;Keinath 2010). Most information about diseases caused by D. bryoniae focused on melons or cucumber but not yet on pumpkins.…”

“…Most information about diseases caused by D. bryoniae focused on melons or cucumber but not yet on pumpkins. The fungus can infect any stage of plants and shows a variety of symptoms according to the crop and stage concerned; furthermore it can be seedborne, air-borne, or soil-borne (Lee et al 1983;van Steekelenburg 1983;Bruton 1998;Keinath 2010). Black rot is an important pre-and post-harvest fruit rot of pumpkins which seriously reduces yield and quality (Zitter and Kyle 1992;Sitterly and Keinath 1996;Babadoost and Zitter 2009).…”