The drugs used to preserve the flowers and fruits of navel oranges include gibberellins, natural brassinoids and cytokinins. When using gibberellin, usually when 2/3 of the flowers have faded, prepare the drug and spray it on the flowers and fruits. Use it again after an interval of half a month, and add some urea when using it, so that the effect will be better. good. When using natural brassinoids, it can also be used when 2/3 of the flowers have faded, or when the fruit has grown to 0.4~0.6cm.