Provided are: a liquid for treatment of Citrus greening disease, which is capable of curing citrus trees with Citrus greening disease and a treatment method using the liquid. The liquid for treatment of Citrus greening disease contains Fe ions and at least some of the Fe ions are present in the form of Fe2+ ions. This treatment liquid contains a predetermined amount of Fe ions and an acid. Citrus greening disease is able to be cured by spraying the treatment liquid onto leaves of citrus trees infected with Citrus greening disease or by pouring the treatment liquid on the roots of citrus trees infected with Citrus greening disease.
