TheGardenLady received this question from Manuel:
My [avocado] fruit is falling off the vine. The avocado is turning black. My tree is ten years old sits on a hill. I always get a lot of fruit. What can I do?
Like most plants, avocados have their problems. Some problems can be treated and other problems, science has not found the cure. Avocados have a number of problems that growers know about. See here.
But as an online garden blog that tries to answer plant questions, some of these questions are difficult to figure out with such a brief description and so few photos. Also, the best place to ask certain questions is the area where these plants are grown in quantity.
TheGardenLady recommends that the person or anyone who has a serious avocado problem, call the California Master Gardeners – not to email them – and then you can talk directly to someone about your problem, giving all the details you think are pertinent and also to answer their questions about the plant. The people who answer the calls are horticulturists who have studied the plants in their area. If they tell you they cannot answer your problem about the blackness of the tree and its subsequent death, ask them to give you the telephone number of the agricultural extension where you could get answers. Here are some numbers to connect you to a qualified person to help you.
You can also buy a kit to test your soil to see if there is a soil problem for growing avocados or other plants.
And if you want to spend the money to find out what your specific problem is, if Master Gardeners cannot identify it from your phone call, there is a fairly expensive kit you can purchase to be filled with samples from your dead avocado tree or any other diseased plant that you cannot identify, that can be mailed to a research lab for scientists to determine the problem. If you want this kit, ask the Master Gardener you are speaking to about it and how to buy it. Usually people get the answers to their questions from the Master Gardener horticulturalists before having to resort to this last test.