DEAR DR. CHLOROPHYLL: “We inherited a big avocado tree when we bought our house in Berkeley six years ago. The fruit is great (I think it’s a Fuerte) but I’m wondering if I can do something to make it produce more consistently. Some years it bears like crazy. Last year there was hardly anything. The pattern seems random, and since we “share” the crop with the squirrels, what do you prescribe?”

YOUR BIGGEST FAN

DEAR FAN: The uniquely flavored avocado fruit is produced after the uniquely configured avocado flower is pollinated, God willing and the creek don’t rise. No pollination, no fruit. Some pollination, some fruit. Mass pollination, guacamole for days. Honeybees are the pollinators. No bees, no pollination, no fruit; some bees, some pollination, etc. Everyone knows about Type A and Type B personalities. There are also Type A and Type B avocados. Pay attention, this gets complicated. The avocado flower has both male and female parts in the same flower. Type A flowers are receptive to pollen in the morning, but don’t release pollen until the afternoon of the following day. Type B flowers (like your Fuerte) are receptive to pollen in the afternoon, but don’t release pollen until the following morning. Most avocados are self- fertile and under ideal conditions produce enough flowers opening at different times that pollination occurs and good crop results. However, Berkeley is far from an ideal environment for these tropical natives, and both honeybees and flower openings are affected by changes in temperature, humidity, rain, cloudiness, wind and frost, none of which are under your control. What you can do is plant both A and B types and lots of flowers to attract bees. That way there will be avocado pollen, flowers receptive to it and bees toting it back and forth all day long.

Type A Avocados: Hass, Mexicola, Pinkerton, Reed.

Type B Avocados: Fuerte, Jim, Zutano.