Q: Many of my mangos are dropping while they are still small. What can I do?
C.B., Pembroke Pines
A: It’s normal for up to 80 percent of immature mango fruit to drop at this time of year. Trees typically shed excess fruit when fruit are marble size, since more fruit is set than the plant can bear to maturity. Fruit can also drop for other reasons.
In Florida, most mango varieties do not produce a fruit on every flower spike (called panicle). There are also differences in the number of fruit that reach maturity due to genetics. Varieties such as “Tommy Atkins” and “Haden” typically don’t bear more than one fruit per panicle, whereas “Sensation,” “Irwin,” and “Nam Doc Mai” often carry two or more fruits per panicle.
If your tree is dropping so many fruit that the tree bears very few fruit to maturity, this could be caused by too much rain or heavy dew during blooming and fruit sets. This can cause fungal disease problems in the flowers and immature fruit, or inadequate nutrition.
One of the major reasons for a heavy early fruit drop this year is that the very young fruit were infected with the fungal diseases anthracnose, and/or powdery mildew. It’s too late to spray for these diseases this year since your fruit are already dropping. To avoid these fungal disease problems, spray your trees when they begin to form the flower spikes. There is a fact sheet explaining how to manage mango diseases on this web page http://miami-dade.ifas.ufl.edu/Pests_HT.shtml
Some mangos, especially “Haden,” tend in some years to produce small fruit in which the seed’s embryo never develops. These fruit are shed before they become very large. Some varieties, like “Edward” and “Earlygold,” almost always produce a percentage of fruit with aborted seeds. The fruit will typically develop to its full size.
Sometimes the cause of premature fruit drop is from the cold weather during bloom and fruit set. Usually the most affected varieties are the early bloomers including “Glenn,” “Haden” and “Cambodiana.” The cold damages the developing embryo in the seed. The fruit starts to develop but because of ethylene gas given off by the damaged embryo, the fruit is triggered to drop before maturity.
To see if cold temperature was the cause for your fruit dropping, cut open the fallen fruit. Even if there is a small speck of brown in the seed, that’s enough damage to stop fruit development.
To learn how to care for your mango, please read this UF publication: https://edis.ifas.ufl.edu/mg216
Send undamaged (live or dead) insects in a crush-proof container such as a pill bottle or film canister with the top taped on. Mail them in a padded envelope or box with a brief note explaining where you found the insects.
Do not tape insects to paper or place them loose in envelopes. Insect fragments or crushed insect samples are almost impossible to identify.
Send them to the address of your county extension office, found in the blue pages in the phone book under county government.