The key to profitability is producing consistent avocado crop sizes year after year. In order to do so, a grower must use proactive cultural management techniques to balance shoot growth, fruiting and root growth — balancing the three simultaneous growth cycles. Ideally, an avocado tree should produce a similar crop each year. But avocado trees have a tendency to adopt an alternate bearing cycle — an on-crop/off-crop cycle across two years that results in a large crop of small avocados in one year, followed by small crop of large avocados the next year.
Once started, an alternate bearing cycle can be self-perpetuating. A large on-crop inhibits fruit set and flowering, leading to a smaller crop next year. Likewise, a small off-crop leads to robust fruit set and flowering and a large crop the following year.
What spurs alternate bearing cycles?
Off crops can be caused by:
- Climactic events — freezes, low or high temperatures
- Water-deficit stress during bloom or fruit set — causes low flower numbers or excessive flower and/or fruit drop
- Under fertilization — causes excessive fruit/flower drop (abscission)
- Over pruning — results in low flower or fruit numbers and excessive vegetative shoot growth
On crops can be caused by:
- Excessive fruit set
- Excessive fruit retention