CSLB C-27 Landscaping ContractorPlanting and LandscapingMedium
A client notices that their mature avocado tree, which produced abundant fruit last year, is bearing very little fruit this season despite appearing otherwise healthy. They are concerned about the sudden drop in yield. What is the most likely reason for this phenomenon in avocado trees?
- ALack of water during the flowering period.
- BOver-fertilization with nitrogen.
- CBiennial bearing (alternate bearing).
- DInsufficient pruning last winter.
Show answer & explanationAnswer & explanation
Correct answer: C. Biennial bearing (alternate bearing).
Avocado trees are well-known for biennial bearing, also called alternate bearing, where a year of heavy fruit production is often followed by a year of light or no production. This is a natural physiological process for the tree.
Why the other options are wrong
- A. While water is crucial, a sudden drop in yield without other health issues points away from a simple lack of water.
- B. Over-fertilization with nitrogen would typically promote vegetative growth at the expense of fruit, but a sudden 'off' year is more indicative of biennial bearing.
- D. Pruning typically aims to encourage fruit production or shape the tree; insufficient pruning would not usually cause a complete 'off' year for fruit.
Biennial Bearing
A natural physiological phenomenon in some fruit trees, like avocados and some citrus, where a heavy crop year is followed by a year of little to no fruit production.
- It's a self-regulating mechanism by the tree.
- Can be exacerbated by environmental stress or poor cultural practices.
- Pruning and thinning can sometimes help manage, but not eliminate, the cycle.
Memory trick: Biennial Bearing: Big year, Bare year, Balance.