Flowering is in full swing here in Georgia. While most of our trees still have tightly closed buds, we are starting to see flowers open and even fruit set in some areas. We are definitely seeing a lot more flowering this year compared to last year, but it’s still too early to tell for sure what our crop load is going to look like this year. Typically, only 0.5-3% of the flowers you see on the tree will set a fruit that makes it to harvest. The majority of this loss is going to happen over the next several weeks as the trees undergo two rounds of natural abscission which we’ll talk about below.
First Round of Abscission
The first round will occur right around fruit set and we can expect that to start any day now and continue over the next couple weeks. This first round of abscission is largely hormonally driven and is dependent on pollination and successful fertilization of the ovary. If the ovary isn’t fertilized, abscission is triggered and abscission will occur. This abscission occurs at the base of the stem at abscission zone A. The ovaries dropped at this stage will be smaller than a tic-tac or pea (Figure 1).
Second Round of Abscission
The second round of abscission is June Drop. This drop will typically occur in May or June and often overlaps with the ovary abscission seen with the first round of abscission . June Drop is a natural thinning process trees go through to reduce competition for carbohydrates. On a given tree, each fruit is competing for a limited amount of resources. The weaker fruit will drop during June Drop while the stronger ones will continue to grow and develop. Depending on the variety, fruit may be anywhere from pea-sized to gumball sized when they drop (Figure 2). Regardless of size, fruit dropped during June Drop will always abscise from Abscission Zone C which is located between the fruit and the calyx. The calyx will remain on the tree while the fruit drops(Figure 3).
Summary
Our citrus trees are loaded with buds right now which is a promising sign! However, we will undergo some flower and fruit drop in the coming weeks as the trees thin themselves out. We’ll get a better idea of what our crop loads are going to look like as buds continue to break and fruit start to set.
We’ll continue to post updates on how things look throughout the season!
