Silver nanoparticles inactivate sclerotial formation in controlling white rot disease in onion and garlic caused by the soil borne fungus Stromatinia cepivora

• Published in: European journal of plant pathology 2021-08, Vol.160 (4), p.917-934
• Main Authors: Darwesh, Osama M., Elshahawy, Ibrahim E.
• Format: Article
• Language: English
• Subjects: Agriculture; Antifungal activity; Biomass; Biomedical and Life Sciences; Chemical control; Combined treatment; Culture media; Deactivation; Dextrose; Dipping; Disease control; Ecology; Field tests; Fungi; Fungicides; Fusarium oxysporum; Garlic; Germination; Inoculum; Life Sciences; Mycelia; Nanoparticles; Onions; Plant Pathology; Plant Sciences; Potatoes; Sclerotia; Sclerotium cepivorum; Silver; Soil microorganisms; Soils; Spraying; Tebuconazole; Transplants; Vegetables; White rot
• ISSN: 0929-1873; 1573-8469
• DOI: 10.1007/s10658-021-02296-7

Under Egyptian conditions, the white rot disease, caused by the soil borne fungus Stromatinia cepivora , causes a major problem in the production of onion and garlic crops. The current study aims to control this disease using silver nanoparticles (AgNPs), biologically synthesized by Fusarium oxysporum . In in vitro assays, carried out on Potato Dextrose Agar (PDA) and Potato Dextrose Broth (PDB) media, the biosynthesized AgNPs at various concentrations i.e. 40, 80, 120, 160 and 200 mg/L, showed a great and promising antifungal activity against the linear growth, mycelial biomass and scelerotial germination of S. cepivora isolates. With increasing of AgNPs concentration the antifungal activity was increased and the application of 200 mg/L produced maximum antifungal activity. It was noted that AgNPs at all concentrations inactivate sclerotial formation on the treated culture media and to our knowledge; this observation is considered a first report. The protein profile of AgNPs-untreated fungal biomass showed the presence of band at 28 k Dalton. This band was absent in the profile of AgNPs-treated fungal biomass and may be related to the formation of sclerotia. In the potted experiment, the chemical control using of tebuconazole recorded the highest efficiency in reducing the incidence of white rot disease. Significant reduction in the incidence of white rot was obtained with AgNPs applied as transplants/clove dipping or stems base spraying or dipping plus spraying. In general, the combined treatment was more effective than these methods used individually. In field experiments, the double treatment, which included the treatment of dipping and spraying, led to a significant reduction in the disease incidence, whether in the field with a low or high level of sclerotia. Under low inoculum levels, significant control was achieved with all methods used. However, the method of dipping only did not give significant control of garlic white rot under high inoculum levels. Application of AgNPs provides an improvement in the growth and yield of bulbs for both onion and garlic plants grown under field conditions. Therefore, AgNPs can be used as nanofungicide against white rot disease and as nanofertilizers for onion and garlic productions.