I live in Hamilton ,New Zealand and I hava a Avocado Tree which is 8 yrs old, it is very healthy and has flowered for the second year now.This year the tree was covered in flowers, and then fruit, that reach a size of about 5mm in diameter and then they all fall off the tree.
Is this due to strong winds or is there some other possible problem?
Any comments would be helpful.
Many thanks Jeff Adams.

I have been told that fungus causes failure to set fruit and fruit drop. I was told to spray the tree with copper fungicide weekly from first blossom until fruit set. I just finished the first trial and can't tell yet the results. Seems that it couldn't hurt.

A dramatic change in the weather -- such as wind, high temperature, and/or very low humidity --can cause avocado fruit to drop.

jean

Try a good mulch with a good compost and added potash, usually helps with trees that have trouble setting and keeping flowers that set fruit. works for all fruit trees, they must have the potash to get good flowers and fruit set.
Avocados are a very hardy beast, but don't like wind.
GayT

There are many reasons for fruit drop.

The first consideration is pollination. Many avocado trees require two different cultivars to insure pollination because they are either type A or B flowering. Having a second plant of the opposite stage increases the potential for pollination. There is a need for both a source of pollen and the receptive female phase of the flowers, plus a pollinating insect to achieve fruit.

Small fruit, subject to low temperatures, will likely cause the developing seed abort. In most cases the fruit drops, but in some instances the fruit continues to develop without the seed enlarging - this fruit is termed "cukes" by growers and sometimes sold as "cocktail avocados" by enterprising produce people.

Strong winds produce a wind chill effect on the plant and result in damage to small, developing fruit by lowering its temperature below what an air temperature reading reports.

Try constructing a 3 sided plastic wind break around the tree and see if this helps. You might also see if there are sources of named cultivars of avocados in your area and graft several different selections to replace some branches.

Good luck.

Claude Sweet
San Diego, California
USA