There are better fungicides to use but one needs an applicator's license to purchase and spray them. So you will have to calculate the sentimental value of your trees, plus the charges of commercial applicators, versus buying a more disease tolerant tree with better rootstock, planting them and planting them on a mound.

The copper based fungicides are becoming useless or totally ineffective as the years go by.

Your trees like clay soil OK. They do not like any texture soil that does not drain. You can do a search for 'soil percolation test' you can do your self to find out how well your soil drains. Both apricot and cheery are not recommended for growing along the cool California coast. Summer fog and moisture causes fungus diseases and mild winter temperatures seldom will meet the chilling requirements. Al

Do you have goo coming out of the trunks? Is that your "fungus"? If so, look up gummosis. Multiple possible causes for this.

If you dug 2 ft. x 2 ft. holes and backfilled with amended backfill or planting mix you may have created sumps that collected water around the trees.

Here is a link that might be useful: Planting Fact Sheet

How saturated is your soil getting. In general apricots are more tolerant of wet soils then cherries. the type of rootstock can make a big difference. If the soil stays saturated for a prolonged period, your cherries will probably not survive. There isn't really anything you can do at this point.

Can you post a picture of the damage? It is hard to say what you have based on your descripion. Pictures are very helpful.

Starting over again with the right root stock, growing them in raised beds with quality potting soil on the top, and uncovering the upper inch or two of the treeÂs roots to the open air, might make growing fruit trees possible for you. After losing several trees and rose bushes to oak root rot, armillaria, itÂs working so far for me. ThereÂs an unknown wild fruit tree that blooms, but never sets fruit, suckers, and thrives under the oak tree with the infection. The wild fruit tree is around 15 feet tall, has large black thorns. IÂm grafting some of its suckers with the scions and buds I want, and hope to replace the tree eventually with something that fruits.
Uncovering the top root structure keeps it dryer, and makes it more difficult for the fungi to get established under the bark, run up the tree, and kill it.
Also, fungus infections are very place specific. One plant will die all of a sudden, and all the plants around it thrive. I replace the dead plant with one in a large pot, half submerged. It thrives also, 90% of the time. The infection only seems to be in a small section of my back yard. There are claims about Mycorrhizal fungi "injections" of healthy fungi helping keep the plant overall healthy, and more resistant to deadly infections.
Fungi infections are not easy to live with, but with a few adjustments, a productive home orchard may still be possible.

Here is a link that might be useful: Oak root fungus on grapevines

My 6 acres are full of Armillaria but are no problem for my orchard trees. Summer watering is what causes the root infections of Oak Root Fungus. The mushrooms that appear around the trunk at soil level are the fruiting bodies of the fungus. By the time these appear the fungus has done enough damage to the roots to insure the trees terminal decline. Some of my fruit trees are 50 years old and have never been summer watered. Al

Since Armillaria needs moisture to live I've figured irrigation helps it become a garden pest. However, it sometimes also takes out patches of trees in the forest and other places where there is little or no irrigation being undertaken. So, it would seem you don't necessarily have to water to see it cause significant mortality.

I can walk through my forest and find oak trees with the Armillaria mushrooms on the trees trunk. These trees never get summer water applied, but the soil water level is high enough to suit the fungus and the tree will eventually fall. Two weeks ago a very large old oak fell across my road from this very cause. I have so many old trees on the ground I never cut a tree down for firewood. Al

Hey Al,

When you first put in your fruit trees...did you water them? If you did...when did you stop? Mine are about 4 years old and in "good" soil and believe me...I would love to stop watering them in the summer. Currently I am giving them approx. 18 gallons a week. Thanks so much

btw...my neighbor has an older orchard (approx 30 years) and he gets complete leaf drop by Sept if he does not water.

Villandry I grew up on this soil. We were mainly prune and grape growers, all dry farmed. If you plant in January with bareroot stock, which is what I do, you will need to water through to fall rains probably Nov. Soils vary so much you will have to watch your trees for signs of stress. This soil is Clay/Loam and at least 6 feet deep so it retains moisture well. If you have sandy soil or plant dwarfing rootstock you will have to summer water. Al

Ah....6 feet of soil. Thats the answer. I can only dream about 6 feet of soil.

Thanks for answering my question.

btw...finally got a Baby Crawford peach. Now I just have to wait 4 years for some real fruit.

Just lost an apricot tree to Phytophthora root rot in clay soil in Rio Grande valley central New Mexico. Tree was doing great for 4 years, then died suddenly after warm winter with possibly too much water. Other fruit trees (plum, peach, nectarine, pear, persimmon), are fine, but worried about the Lapin cherries. Going to experiment with planting daikon radishes to break up the clay soil.