Smiltsērkšķu sēņu ierosinātas slimības un to izplatība Latvijā = Sea buckthorn diseases caused by pathogenic fungi and their occurrence in Latvia

Sea buckthorn (Hippophae rhamnoides L.) is a native species in various regions of Asia and Europe. It is cultivated as a multipurpose horticultural species for food, pharmacology, cosmetics, and environmental conservation. Diseases in natural populations and managed landscapes have increased, endangering sea buckthorn growth and cultivation worldwide. Sea buckthorn diseases caused by pathogenic fungi are widespread but still poorly studied. In the previous studies, commercial orchards and wild habitats in Latvia had been surveyed, and a fungal collection isolated from branches, roots, and trunks with various disease symptoms was established. In order to explain the role of several pathogenic fungi in causing sea buckthorn diseases, the revision of the collection was made, and the analysis of the identified species complex in relation to host plant symptoms was carried out. The isolated fungi were identified based on morphological characters and analysis of ITS/5.8S sequences. The most often reported symptoms were dead buds and leaves, cankers and cracks on trunks and main branches, and necrosis of various tissues on branches and roots, resulting in the death of the shrubs. The analysis of the observed symptoms and the isolated pathogenic fungal species indicates that sea buckthorn diseases are often of a complex nature, and it is necessary to explain the effect of each species on the plant, including complex infections. In-depth studies on the interaction of the potentially most important pathogenic fungal species (e.g. Hymenopleella hippophaeicola, Eutypa spp.) with sea buckthorn were initiated by conducting bioassays under controlled conditions on different cultivars.