Flower Bud Induction Overview and Advisory

Flower Bud Induction

 

NOTICE FOR CITRUS EXTENSION AGENTS & SPECIALISTS AND GROWER NEWSLETTERS
The following information has been developed as part of the Decision Information System for Citrus

L.  Gene Albrigo, Horticulturist Emeritus
Citrus Research & Education Center, Lake Alfred, FL

Archives of past Flower Bud Induction Advisories

 

FLOWER BUD INDUCTION ADVISORY #6 for 2012-2013-04/09/13

NOTICE FOR CITRUS EXTENSION AGENTS & SPECIALISTS AND GROWER NEWSLETTERS
The following information has been developed as part of the Decision Information System for Citrus.
L. Gene Albrigo, Horticulturist Emeritus
Citrus Research & Education Center, Lake Alfred, FL

This is a service to our citrus growers posted on the CREC website.  The internet Expert System on intensity and time of bloom can be accessed anytime: http://disc.ifas.ufl.edu/bloom.

Current Status: At the last advisory in January, the issue was warm weather pushing the development of the flower buds to a very early bloom. That may have been the last consistent warm weather we have had until now.  We did have a very light bloom in February followed by a moderate bloom in the first half of March.  Everything was on track for flowering ending in early to mid-March, but the weather turned cool and flower development stopped.  This occurred at a transition between early-mid oranges and Valencia bloom, which is usually a few days later due to the effect of the current crop delaying bloom.  Instead of mid-March, we now have Valencia bloom just completing its flowering cycle on 9 April. The Valencia bloom dates are within the historical spring bloom period for Florida citrus. For some time it looked like Valencia bloom would be very sparse.  Now it appears to be an average bloom.

The last stages of flower development are very sensitive to cooler temperatures and development just stops under these conditions, but it did not affect the level of flowering.  For Central Florida, the three cohorts of flowers were still produced after about 650 accumulated hours below the threshold for induction, <68 o F; after 800 to 900 hours of induction, and the last wave had 850 to 1100 hours of induction.   The least induction occurred in the Indian River and south Florida areas with about 850 hours, which still should be adequate.

Now instead of an overall early bloom year, we have early flowering cultivars early and later blooming Valencia and mandarins fairly late in the flowering season.  This will probably result in early maturity for early-mid season oranges and a significant gap before the Valencia crop is ready for harvest for processing.  Valencia fruit should have a much wider range of internal quality on each tree than normal since some much earlier bloom occurred on the same trees that are now in bloom to petal fall stages for their last flowering cohort.

Early-mid cultivars will probably start the May-June drop period no later than early May, but Valencia and mandarin cultivars may be as late as early June before they shed excess fruit.  A final advisory will assess overall crop potential on healthy trees at the end of June.

If you have any questions, please contact me at (albrigo@ufl.edu).