Managing Avocado Fruit Drop

Very often a great source of frustration for an avocado grower is to see a large percentage of the newly-set fruit dropped by the avocado tree. This drop of new fruit is normal and thought to be the trees’ means of getting rid of fruit with defective or weak seeds. If the drop does not occur, the trees are likely to carry a crop with an excessive number of cukes (these are seedless fruit that remain small). Newly-set fruit that remain on the tree until harvest tend to grow the fastest in May. The slower growing fruit tend to be those that are shed by the tree in the June drop.

While it is difficult to decrease the amount of fruit that are dropped, California avocado growers can prevent excessive avocado fruit drop through good cultural management, especially when the newly-set fruit are in a rapid growth phase.

• Correct irrigation practices are needed to maintain a healthy tree when the new fruit are growing rapidly — don't overwater or underwater the trees.
• Exposing the trees to unnecessarily dry soils can cause more fruit to drop than if the soil under the trees was at the proper soil moisture content.
• Do not over stimulate the growth of the tree; the shoots that grow through the flowers compete with the newly set fruit.  If growth is excessive a smaller crop may result.
• A modest amount of new growth on the avocado tree is useful to shade the new fruit and to start replacing the old leaves shed after winter.
• Consider your harvest strategy. If there are mature fruit still on the trees, along with your new crop, then excessive numbers of this fruit can also compete with the new set, potentially reducing the new crop.