Influence of environmental conditions on the virulence and distribution of Orobanche cumana Wallr. in the Republic of Moldova

Abstract

The parasitic angiosperm Orobanche cumana is present in the main sunflower-producing countries around the world. In recent years, more aggressive races of broomrape have evolved and the parasite has rapidly spread to new areas. A similar trend has been observed in the Republic of Moldova. At the beginning of 1950s, broomrape was detected in Moldova, especially in the southern areas. Currently, all the known races of Orobanche are present in the country and the parasite has expanded considerably on new areas in the center and north. Based on these results and the data reported by other authors, related to influence of climate change on the phytosanitary situation, we studied the interdependence between the climate and the distribution of Orobanche cumana Wallr. over different parts of the Republic of Moldova. Prevalence of broomrape infection mainly in the southern and central part of the Republic of Moldova and its sporadic presence in the northern part can be influenced, not only by short rotations, type of sunflower hybrids grown and soil parameters, but also by the weather conditions such as higher temperatures and lower humidity in the south and center. Based on multiannual data and trends observed in recent years, characterized by an increase in temperature and decrease of relative humidity, we conclude that climate change will create favorable conditions for infecting sunflower plants in all the areas where sunflowers are grown, including the expansion of broomrape to the north of Moldova.