Species spectra, distribution and host range of cucurbit powdery mildews in the Czech Republic, and in some other European and Middle Eastern countries

Abstract

The occurrence and geographic distribution of powdery mildew on cucurbits was studied in the

Long-lasting changes in the species spectrum of cucurbit powdery mildew in the Czech Republic - influence of air temperature changes or random effect?

“…Measured differences in ecological requirements of both species match well their reported distribution under natural conditions. P. xanthii is common in subtropical and tropical areas and on greenhouse crops in temperate areas, while G. cichoracearum occurs more frequently in temperate and cooler areas (Křístková et al 2009). Both species occur on cucurbits under climatic conditions of the Central Europe.…”

“…Both species occur on cucurbits under climatic conditions of the Central Europe. Since the 1960s, P. xanthii has been reported as frequent or even predominant as the causal agent of cucurbit powdery mildew in many parts of the world ( Jahn et al 2002), as a single species or in mixed infections with G. cichoracearum (Wichura 2007;Křístková et al 2009). At the end of the 1970s, P. xanthii was not detected on field cucurbit crops of Bohemia and Moravia, i.e.…”

Fungicide Resistance in Cucurbit Powdery Mildew Fungi

“…This fact does not correspond to the situation in Czech CPM population in relation to azoxystrobin in the year 2007. This could reflect the structure of the CPM population in Central Europe, where Gc is propably the most important CPM pathogen on field cucurbits (Lebeda, 1983;Křístková et al, 2003Křístková et al, , 2009) and CPMs are highly variable in their pathogenicity and virulence (Jahn et al, 2002;. In many parts of eastern Asia and the northern Mediterranean area, strobilurin resistance in CPM has developed, sometimes within the first season of use (Hollomon & Wheeler, 2002).…”

“…Powdery mildew is the major cause of losses in production of cucurbits worldwide (Cohen et al, 2004;Křístková et al, 2009;Lebeda et al, 2007b;McCreight, 2006) (Fig. 1a,b and 2a,b).…”

“…3a,b and 4a,b). Their distribution and relative occurrence varies throughout the world (Bardin et al, 2009;Křístková et al, 2009;Pérez-García et al, 2009). For example, both Px and Gc are important in Central Europe whereas Px occurs almost exclusively in the USA.…”