Pua Ko, Sugarcane Flowers Old Plantation Days , September 2013

September is the month for sugarcane flowers or as we called it “tasseling”.  Wait you say, I do not see any cane flowers in September, that usually occurs in the winter!  Well we are both right.  Late in the month of September the shortening day lengths trigger an internal clock within the sugarcane plant to initiate a flower bud.  This flower or tassel will not emerge and be visible to the eye until sometime in November or December.  To us sugarcane agronomists it was VERY important to know what time of the year the tasseling trigger was set because flowering reduced sugarcane yields and stops all cane growth.  And most importantly we had the ability to actually control and stop the flowering process.

Sugarcane tassels appear in November and they are quite a beautiful show.  The fields light up with slight pink to mauve tones of soft waving plushes of flowers.  The flowers themselves are quite small but there are thousands of them on the numerous tendrils of the tassel.  I have often seen people on the side of the road cutting down cane stalks to display the tassel in their homes within flower arrangements.

When a cane stalk flowers it terminates the growth at the apical meristem.  All forward growth of the plant is stopped and the stored sugar within the plant is used to produce the tassel and attempt to procreate a seed.  This was not a desired action when your job is to harvest and make as much sugar per acre as possible.  Early sugarcane agronomists learned that you could control or limit flowering if you stressed the plant by withholding irrigation water at the time at the September initiation period.  That doesn’t work when you’re on the Hamakua coast and it rains all the time, so how did we control flowering here on the Big Island?  We used aerial applied chemicals.  A month or two back my article featured Crop Dusters.  Well here we are with a very important application that was done by the aircraft, to stop the cane from flowering.

One of the first chemicals used was paraquat!  Yup, that’s the stuff you probably heard all about, pretty toxic.  We applied this herbicide in weak concentration to the cane right at the period of flower initiation…it had to be done exactly within a nine day period near the end of September.  Any earlier or later the action will not work.  The paraquat stressed the plant artificially and stopped it from creating a flower bud.  Using paraquat was quite dangerous and there were a few incident of nearby crop damage from unexpected drift.  Fortunately a new chemical was found and registered for cane that was not as hazards, and it was natural!  Ethylene gas.  Ethylene is a naturally chemical in plants that helps them change from active growth to inactive growth.  Sometimes it triggers flowers as in Pineapple where it was applied to initiate flowers and get pineapple to fruit anytime of the year you wanted.  In sugarcane the ethylene that was applied worked that opposite way, it stopped the flowering process!