Geographical distribution of sunflower phomopsis in russia and neighboring countries in modern agrocenoses

Abstract

Sunflower Phomopsis spread in Russia and neighboring countries of the former republics of the USSR everywhere and nowadays poses a serious threat to crops, Initially, disease manifestedin limited way in Moldova, then in Ukraine, soon began to grow in Russia, and then in Kazakhstan. The article presents the results of multi-years of research for the period 1989-2018. The causative agent of the disease was identified as Phomopsis helianthi and its pleomorphism was revealed. The diagnostic signs of the pathogen and symptoms of the disease are indicated. Its epiphytotiology has been studied and the sources of infection, which are a and p conidia, and ascospores. The latter as an aerogenic source of the pathogen and nowadays are one of the determining factors for the expansion of the disease in these countries. The role of seed infection in the initial appearance and distribution of fomopsis on sunflower has been revealed. In the system of GIS technology, phytosanitary zoning of the sunflower phomopsis is established according to the degree of its manifestation in Russia, Moldova, Ukraine and Kazakhstan.It was created a map of the geographical prevalence of the disease, representing the long-term territorial forecast of Phomopsis. It allows you to identify possible trends for further geographical increase in the severity of the disease, taking into account the hydrothermal conditions in the agrocenosis with sunflower. Currently, to limit the disease requires the creation of effective protection of sunflower using resistant varieties and hybrids.