TheGardenLady received this question from Larry about his avocado tree:
My tree is 7 years old and is now bearing fruit. There are many avocados that are turning black and are falling off. We’re in California near the coast in Arroyo Grande. I water my tree twice a week. Most of the fruit looks great, but I’m concerned about the black ones that are dying?
Fruit trees in general often have problems that may be beyond a home owner’s ability to manage. Often fruit trees need to be sprayed and some of the sprays are toxic. One horticulturist I know does not believe home owners should even waste their time raising fruit trees in the home garden and should leave this job to the professionals. That being said and not seeing your avocado problem, I am guessing that your tree has a fungus. I am not saying this because I know for certain, but “Fungus is the most serious avocado disease in California.” Here is a chart of some of the problems avocados can get. Since that is my educated guess, it is still a guess so I would not want to diagnose any problem without seeing your tree or its fruit. Read this:
“Fungus thrives in excess soil moisture. Overâ€irrigation and poor drainage can by your problem because you are growing the plant in a pot. The fungus may attack trees of any size or age. Your plant may have an absence of feeder roots that prevents moisture uptake so soil under diseased trees stays wet.”
What I suggest is that you go online or call the California Avocado Comm or (949) 341-1955 from the hours of 8:30 a.m. to 4:30 p.m to see if they will diagnose the problem and recommend how to treat your tree.
Or take a good sized sample of your avocado fruit to your local Master Gardener office and ask them for their diagnosis and recommended treatment. Each California county has a Master Gardener office. One such county has this site. Visits to these sites are usually free.