Study on Antifungal Activity and Ability Against Rice Leaf Blast Disease of Nano Cu-Cu₂O/Alginate

Rice blast disease due to Pyricularia oryzae fungus is one of the most destructive ones for rice, causing serious losses in yield and quality in Vietnam and other countries. Studying to develop new fungicides to control the fungal disease effectively is essential.

The sodium alginate-stabilized Cu-Cu₂O nanocolloidal solution with a size of about 4 nm and the Cu concentration of 5, 000 mg/L was prepared by chemical method. The antifungal activity in vitro against P. oryzae and the ability to control the rice blast disease in the greenhouse of nano Cu-Cu2O/alginate were assessed.

The nano Cu-Cu₂O/alginate exhibited highly fungal activity with the IC50 of 17.8 mg Cu /L. The disease severity of nano Cu-Cu₂O/alginate treatments was in the range of 9.38 - 18.54% in comparison with 47.57% of the untreated control. The grain yield of rice plants treated with nano Cu-Cu₂O/alginate increased compared with that of the untreated control, and the Cu content in polished rice was almost the same as that of usually cultured polished rice. Thus, the nano Cu-Cu₂O/alginate can be used in agriculture as a plant fungicide, especially for rice cultivation.