Splitting Citrus Fruit Questions

“My 60 – 80 year old orange tree has, for the three years we have lived here, regularly produced abundant crops of many hundreds of exceptionally delicious fruit each year, February – June.

In the last four weeks it has been dropping oranges at an increasing rate, by now many dozens a day, totaling over 300.

The fruit is splitting, leaves are drooping, the canopy is diminishing, and a few clusters of branches have died. There is a tree nearby of the same age and size that does not appear to have any problem at all.

Our tree has not been watered regularly during the dry season, whereas the neighboring tree is surrounded by a watered lawn.

It was given fertilization of nitrogen last year, and we wonder if this, or the lack of watering, could be the cause.

What can we do to save this magnificent tree?”

Splitting citrus fruit is a common problem, especially with navel oranges. Very briefly, fruit splitting is likely the result of stress to the tree and is probably related to extreme fluctuations in temperature, humidity, soil moisture, and possibly fertilizer levels. The disorder is often caused by a combination of these factors rather than by a single cause.

Avoiding fluctuations in soil moisture (I suggest adding mulch under the tree canopy and consistent and ample water, especially during heat spells) as well as fertilizer levels throughout the growing season may help to minimize fruit split.

I believe the leaf drooping and turning over are also symptoms of too little water during the hot season.  The dropping of leaves and resulting thinning of canopy often are the result of too little water on both fruit and ornamental trees. 

For more information go to: cecolusa@ucanr.edu ■