Dr. Greg Partida, who has been teaching at Cal Poly for the last 30 years in the area of Ag Biology and Fruit Industries, gave the lecture on avocados. He has a B.A. from Cal Poly in Agriculture Biology, an M.S. and a Ph.D. in Integrated Pest Management at U.C. Riverside. He was Farm Manager of the University orchards for 23 years and has consulted in the cultural practices of avocado throughout the California production area and in the Dominican Republic.
In California the avocado industry is undergoing radical changes, mostly due to competition from other countries, the increasing costs of production and worker’s compensation insurance. The avocado tree of the future will be no taller than an average man can reach in order to dispense with the use of ladders in the orchard.
It is Dr. Partida’s opinion that any grower with trees that cannot be pruned, sprayed and harvested by a man standing firmly on the ground will be out of business in five years.
His most important point was that most avocados are under-watered. This is particularly important during the flowering period. He is a great believer in mulching and states that you should leave all prunings under the tree to release their nutrients back into the soil. Avocados love cow manure and you should heap aged manure in a donut shape around the tree just as you would spread fertilizer. Do not leave it up against the trunk but pile it up in a ring to out past the drip line so the feeder roots of the tree will come up through the mulch. This goes back to lots of water!!! With roots at the surface the tree needs adequate moisture without sitting in water.
The leaves on a healthy avocado should be 12 to 15 inches long and 8 inches wide. If your tree is under par, Dr. Partida recommends a combination of humic acid and P205 fertilizer used as a soil-drench twice a month for sick trees. The humic acid should be mixed at a rate of 1 oz: 1 gal. humic acid is one of the most biochemically active elements in humus and he swears by it to stimulate wood growth. It is a liquid product derived from decayed organic matter with a capacity to collect plant food elements and release them as the plant requires.
The last recommendation he made that was unusual was to plant three to four varieties of avocado in the same hole to increase pollination, yield and lengthen harvest times. This procedure was backed up by another speaker in his lecture on Backyard Orchard Culture.
“Festival Of Fruit” Pomona, California, June 18 To 21, 2004