Major fungal diseases of onion and their control (in Tashkent region as an example)

The aim of the research work is to determine the most often met fungal diseases of onions grown in the open ground and its fruits during storage in the conditions of Tashkent region, and to develop control measures against them.
The object of the research work. Scientific research was carried out with three onion species, i.e. Allium сера - common onion, A. porrum - leek and A. schoenoprasum - chive.
Scientific novelty of the research work:
During the scientific work 597 herbarium samples of infected onions have been collected in open fields in the Tashkent region, and of onion fruits during storage. 57 species of pathogenic fungi, belonging to 29 genera, 4 phyla, 8 orders and 12 families were identified on these samples. 29 species amongst them were recorded for the first time in Tashkent region. Most of fungi amongst pathogen - 34 species - were representatives of Deuteromycetes, and 10 were species of Basidiomycota, 9 species of Ascomycota and 3 species from the phylum Oomycota.
Genus Botrytis has been represented with 5 species, each of genera of Puccinia, Penicillium, Aspergillus have had four species, and Melampsora and Phyllosticta - 3 species each, and each of the other genera were presented with 1 or 2 species.
Amongst identified 57 species of fungi 22 species were the most distributed and harmful ones.
Results of investigations have revealed that causal agents of downy mildew, rust and smut diseases were obligate parasites, while rest species of pathogenic fungi have belonged to the group of facultative parasites including diseases caused by species of Altemaria, Botrytis, Fusarium, Phoma and Penicillium.
Studies of biological characters have shown that Peronospora schleideniana infected all vegetative parts of plants; Botrytis cinerea has been common on all leaves, calyces, flowers, seeds, bulbs, roots, while rust fungi, mainly infected leaves of plants.
There were 11 species of fungi that infected seeds of onion. Three species of them (Botrytis cinerea, Peronospora schleideniana and Urocystis cepulae) were recorded on internal tissues and 9 species have been found on surface parts of the seeds.
Implementation of research results. The results of the research conducted during 2013-2017 were implemented in onion production farms "Shukhrat ziyo" and "Islomkho’ja Nig’monkho’ja", Zangi ata district and "Temir Qadam Abdirayim" and "Salar fayz" farms, in the Istiqlol agrofirm conditions of the Kibray district in Tashkent region, in total on 6 hectare area (reference from the Ministry of agriculture and water resources dated 29.11.2016 No.02/20-1256).
The structure and volume of the thesis. The dissertation consists of introduction, six chapters, conclusions, list of references and an appendix. Volume of the thesis consists of 120 pages.