"Flower Induction: Pineapple flowering may be delayed or uneven, and it is highly desirable to attain uniform maturity and also to control the time of harvest in order to avoid overproduction in the peak periods. In 1874 in the Azores it was accidentally discovered that smoke would bring pineapple plants into bloom in 6 weeks. The realization that ethylene was the active ingredient in the smoke led to the development of other methods.
As far back as 1936, compressed acetylene gas, or a spray of calcium carbide solution (which generates acetylene) were employed to expedite uniform blooming. Some growers have merely deposited calcium carbide in the crown of each plant to be dissolved by rain. A more advanced method is the use of the hormone, a-naphthaleneacetic acid (ANA) or B naphylacetic acid (BNA) which induce formation of ethylene. In recent years, B-hydroxyethyl hydrazine (BOH) came into use. Treatment is given when the plants are 6 months old, 3 months before natural flowering time. The plants should have reached the 30 leaf stage at this age."