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Alternate Bearing Cycles

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 fertilizationcauses 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