Trehalose or trehalose-6-phosphate, when applied exogenously to citrus trees that are compromised in their growth and development with the condition referred to as citrus greening or HLB, can overcome the deadly effects of the problem. Renewal of tree tissue with trehalose or trehalose-6-phosphate has been documented to begin as soon as 72 hours after exogenous application to the dying tree. The tissue renewal continues with near complete renewal of the leaf canopy, development of fruiting buds, followed by flower development and then development of the flowers into abundant and healthy fruits. Much of what appeared to be dead wood tissue could be covered with healthy new leaves within 2 to 4 months after application. Addition of defined hormones to the soil application of trehalose or trehalose-6-phosphate further enhanced development of new canopy and root tissue.