How can naphthaleneacetic acid delay fruit drop before harvest?

Naphthaleneacetic acid (NAA) is a synthetic auxin, a class of plant hormones that regulate growth and development processes, including organ separation. In horticulture, NAA is specifically utilized as a growth regulator to prevent the premature drop of fruit, such as apples, before the normal harvest time.12

It functions by influencing the physiological processes associated with leaf and organ separation. By applying this compound, growers can effectively manage the timing of the harvest by inhibiting the natural abscission process that would otherwise cause the fruit to detach from the tree prematurely. This application is a standard practice in horticulture to ensure that fruit remains on the branch until it reaches the desired maturity for collection.21