Powdery mildew is a prevalent fungal disease that impacts numerous plant species, including mango trees. It’s caused by Pseudoidium anacardii 1,2 formerly Oidium mangiferae Berthet, in mango trees 3,4,5. It’s a major disease characterized by a powdery white fungal growth that covers plant leaves, inflorescence clusters, and young fruits, but the flowering stage appears to be the most susceptible to infection or during fruit set 1,6 which can hinder photosynthesis and lead to reduced crop yields. Although the fungus is a biotrophic microorganism that does not directly cause plant cell death, as it depends on living cells to acquire nutrients and continue its life cycle 7, through penetrating the plant cuticle and cell wall 8. It may cause serious losses that could be up to 90% when blossoming and growth initiation that negatively affects productivity 9,10. The pathogen develops in dry and cold conditions whilst becoming more severe at 90% relative humidity (RH) and temperature ranging between 20–25°C 11,12.
Disease control is mainly depending on using diverse fungicidal chemicals, but there is a risk that excessive use has detrimental impacts or reinforcing a resistant fungal by additional applications of ineffective fungicides 13 on mango orchards in Egypt. Fungicides such as carbendazim, thiabendazole, and benomyl to which P. anacardii had evolved resistance 11,12,14. However, fungicide rotation with different sites of action or multisite fungicides such as sulfur, dithiocarbamates, and quinomethionates can act efficiently and reduce the risk of the appearance of fungal resistance 11. So, demand for alternative disease management strategies is heightened by the desire to reduce pesticide levels on food crops and environmental health concerns.
Sulfur may act as a phytoalexin and is considered one of the earliest fungicides; it has been used to resist powdery mildew since the nineteenth century 15,16. It's applied sulfur-based fungicides at the early stages of infection or as a preventive measure to achieve optimal results. By interfering with the enzymatic processes within the fungal cells, disrupting their ability to thrive and spread, sulfur can kill spores and mycelia; therefore, it’s useful as a therapeutic or preventive fungicide 17,18. Sulfur penetrates the fungal cells, spores and into cytoplasm, damaging their structure and inhibiting the electron transport chain for respiration directly by modifying crucial protein thiols 19. Sulfur is well recognized for its function in the synthesis of chlorophyll, proteins, and the amino acids as methionine and cysteine 20. A concept was proposed to improve control of powdery mildews by using lower or safe doses of fungicides to reduce the risk of phytotoxicity, harm to non-target species, and environmental hazards 21,22. There is a growing interest in developing nanomaterials for agricultural use, including new crop management techniques and the delivery of nutrients and pesticides 23,24.The featured physicochemical characteristics of nanotechnology that act an effective improvement in the agricultural sector, where nanomaterials are being employed more frequently in agriculture to increase plant biomass owing to their tiny size and vast surface area 25 or pesticides have been able to draw much attention due to their higher efficacy even at very low doses 21. Notably, this nanomaterial has only recently been used on fruit crops, while several studies focused on field crops and a few vegetable crops 25. Sulfur Nanoparticles (SNPs) have been utilized as fungicide and pesticide to combat some plant diseases but till date there are a few reports about that 26,27. Besides, SNPs enhance the growth characteristics of some plants including Tomato 28,29; Rapeseed 27.
Our study hypothesis was that application of SNPs could be highly suppressing the mango powdery mildew. Bearing the above in mind, the objectives of this study are to offer relevant data about the influence of SNPs spraying on morpho-physiological attributes, disease severity index and disease incidence percentage. Furthermore, the productivity and fruit quality.