In December, UC Cooperative Extension Master Gardeners in Stanislaus County offered library classes on planting and pruning deciduous fruit trees. If you missed them, you can find past recordings about this topic on our YouTube Channel, as well as links to helpful publications from UC Agriculture and Natural Resources (UC ANR).

What is a Deciduous Fruit tree?

Deciduous fruit trees lose their leaves in fall, and include apple, pear, fig, pomegranate, nectarine, cherry, apricot, peach, and plum. 

Planting New Trees & Understanding Where Fruit Originates

Sometimes a fruit tree mysteriously dies, and the gardener isn't sure what happened. A common cause is a tree that was planted too deeply. Root and crown rot slowly affect the tree, causing it to die years later. Watch the detailed instructions on how to plant correctly.

It's important to understand how new fruit develops and grows on the tree. Not all deciduous fruit trees produce fruit in the same place. It's important to know this so you don't accidentally cut off fruit spurs and damage your tree's ability to produce fruit. See this video for guidance. https://www.youtube.com/watch?v=-4fgVrf8XHE&t=250s

Publication - Fruit Trees: Planting and Care of Young Trees  https://anrcatalog.ucanr.edu/Details.aspx?itemNo=8048

Fruit Trees: Training and Pruning Deciduous Trees  https://anrcatalog.ucanr.edu/Details.aspx?itemNo=8057

Keeping New Trees Small – the Fruit Bush Method 

Tired of out-of-control fruit trees? If you are planting a new tree, watch this video! It details the Fruit Bush Method, a specific way of keeping fruit trees small. See photos of 5-6' tall fruit trees planted over 30 years ago that continue to produce an ample amount of fruit. https://www.youtube.com/watch?v=ry4YAp6NzdI&t=1s

Pruning Established Trees

If your fruit tree is already out-of-control, read Fruit Trees: Pruning Overgrown Deciduous Trees https://anrcatalog.ucanr.edu/Details.aspx?itemNo=8058 for help. It can take several years of pruning to bring trees down to a manageable height.

Other Helpful Publications

Fruit Trees: Thinning Young Fruit https://anrcatalog.ucanr.edu/Details.aspx?itemNo=8047

What about Citrus Trees?

Citrus trees such as oranges, lemons, grapefruits, lime, and kumquats are evergreen trees and need different care than deciduous trees. It's not recommended to prune citrus trees at the same time as deciduous fruit trees. Wait until spring to prune your tree for size and shape.

We are offering an online class on citrus on January 31, so watch for our registration advertisement in about a week. Locally, we will be teaching at 8 library locations about citrus during March.

If you have apple or pear trees in your home orchard, you are no doubt familiar with codling moths. They're the moths that are responsible for wormy fruit, and unless you take steps to control these pests, they can destroy most of your apple or pear crop.

If you decide to fight them, now is a good time to plan your strategy since the most critical time to protect your fruit from the pest is spring.  Warm spring weather causes most of the first generation moths to emerge within a few weeks. The moths may take 6 weeks or more to emerge during a cool spring. Once they have emerged, the codling moths are still affected by temperature. They do not lay eggs or mate when it's below 62°F at sunset or fly when it's 55°F.

The moths emerge from pupae in early spring about the time when fruit trees are in full bloom. Each moth lays 50 to 75 eggs on fruit, twigs, or leaves. Eggs hatch into larvae which tunnel into the young fruit. Inside the fruit, the larvae feed for several weeks, then tunnel to the fruit's surface and search for protected sites such as under tree bark, in branch wounds, weeds, grass or other litter. The larvae changes first to a pupa, then to an adult and repeats the cycle.

If your trees are isolated by several blocks from heavily infested trees, non-chemical control methods may give you satisfactory results. The trunk and larger limbs of most older fruit trees have loose bark places which make ideal protected sites for larvae to build cocoons and pupate. You can eliminate such sites and destroy any larvae they contain by scraping off the loose bark. Place a sheet of some kind underneath the tree to catch the scrapings so you can collect and destroy them. Do this during the dormant season. In addition, remove any objects on the ground under the tree canopy, such as firewood, large weeds or debris on which larvae might form cocoons.

You can also trap many larvae under bands. Take a 6-inch wide strip or burlap or corrugated cardboard, wrap it around the trunk several times, then fasten it in place with a loop of wire or twine. If you use corrugated cardboard, the exposed flutes (ridges) must be at least 3/16 of an inch wide and face toward the tree; otherwise, the larvae won't form cocoons in them. Place a band on each tree no later than mind-May. During warm weather remove the band once a week, and during cool weather once every two weeks. Destroy all the larvae and pupae under the band, and then put the band back on the tree. Keep doing this until you've harvested all the fruit.

Most of the fruit that falls from the tree contains larvae, which continue to develop. If you pick up and destroy the fruit, you reduce the potential number of moths. The longer the fruit lies on the ground, the greater the likelihood that larvae will leave them to pupate. Therefore, you should collect fruit every day or two. Place the infested fruit in a bag, seal the bag, then leave it in a sunny location for two weeks to kill the larvae. Don't use infested fruit for compost unless you destroy the larvae first. You can destroy even more larvae if you thin the tree of some fruit. At the time you thin (thin apples when they reach the size of Ping-Pong balls), look for and remove any infested fruit. Since codling moth-infested fruit ripens prematurely, you can easily detect such fruit when thinning.

Insecticidal sprays are usually the most effective means of controlling codling moths. Sprays give best control when you apply them just after a large number of larvae hatch, but before they burrow into the fruit.  These times are several days after a period of peak moth flight and vary according to the year and location.

When using any chemical, carefully follow dilution rates and other directions given on the container label.  Do not spray within the number of days before harvest indicated on the label. You can read more details about the life cycle of this pest and management, including chemical controls in the UC IPM Pest Notes: Codling Moth.

Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County where he worked for over 30 years.

That's a good question.  Some question whether they flourish now.  Southern California does not have the landscapes of apples, pears and peaches of Oregon, Michigan, Pennsylvania or even Fresno, but there are nice little niches of persimmon, low chill apple, and even blueberries that thrive in the lower winter chilling environments along the coast and in the south of California.

Here is an example of what might happen to this fruit industry here. A recent, detailed study extrapolate the accumulation of cold periods in Spain over the next 30 years and to the end of the century. This provides growers with important information on the viability of future  fruit cultivation in the various Spanish regions, as it allows them to know if there will be the necessary accumulated cold for the fruits to grow correctly or if they should relocate their crops to other areas.

The results obtained show a general reduction in the accumulation of cold in any future period for all the chilling models and scenarios considered. The reduction is especially significant at the end of the century, under the most pessimistic scenario. These results invite us to strongly commit, not only to adapt but also to mitigate climate change, something that would make an important difference. The probable reduction of cold would threaten the viability of some varieties of fruit trees in the near future, especially in regions where there is currently a low accumulation of cold and there are varieties that require a lot of it.

The study can be viewed at:

https://www.nat-hazards-earth-syst-sci.net/19/1087/2019/

Climate change discussions for California can be found at these websites:

https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=30513

https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=28175

https://www.energy.ca.gov/sites/default/files/2019-07/Reg%20Report-%20SUM-CCCA4-2018-007%20LosAngeles.pdf

An intriguing Santa Barbara apple study grower's observations are worth noting: https://ucanr.edu/blogs/Topics/index.cfm?start=1&tagname=apples

By the way the 'Moor Park'  apricot is not from Moorpark, CA, but from England and the variety has never done very well in Moorpark (http://www.ngr.ucdavis.edu/treedetails.cfm?v=997).

Advice for Home Gardeners from the Help Desk of the
UC Master Gardener Program of Contra Costa County

Client's Request:  Howdy! Can you please help me with my nectarine tree? How should I treat this disease and what is it?

Help Desk Response:  Thanks for contacting the UC Master Gardener Help Desk about the problem you are observing on your nectarine tree. 

Your nectarine tree is showing the classic symptoms of a fungal  disease commonly called "peach leaf curl". It is a common problem for both peaches and nectarines, particularly in years when we have abundant rains as has now occurred this year. The fungal spores that spread the disease can be spread through splashing water and rain.
 
As you may already have noticed, typically the affected leaves turn yellow or brown and can remain on the tree or may fall off; they are replaced by a second set of leaves that develop more normally unless wet weather continues. Most often the disease will not show up on the developing fruit, but occasionally it does affect fruit, causing corky areas to develop on the fruit surface.  Those fruits are still okay to eat—just cut away the affected area.
 
Unfortunately, there is nothing you can do now to stop the disease on your tree. The typical management approach for controlling peach leaf curl is to use a fungicide in the late fall or early winter months when the tree is dormant. The use of fungicides when the tree is dormant can control the development of the spores that usually survive the hot summer months on the surface of the tree bark. Those spores are reactivated by winter rains and attack the leaves when they emerge in the spring.  You should plan now to consider applying such a fungicide in early December, particularly if we are having frequent rains. Just try to schedule the fungicide spraying for a time when you expect to have several successive days of dry weather so that the fungicide can work and not be washed off the tree. You can learn more about peach leaf curl and the use of fungicides to control it at this University of California website:  http://ipm.ucanr.edu/PMG/PESTNOTES/pn7426.html
 
Since fungal spores may also be present on the fallen leaves, it is a good idea to pick up all fallen leaves. Don't put them in your compost pile unless you have a pile that regularly achieves and maintains high temperatures. If your compost piles doesn't have those high temperatures on a regular basis, you can dispose of the leaves in a green bin that goes to a waste company's compost area. Fortunately, those sites typically have compost piles that achieve the high temperatures needed to kill fungal spores.
 
If you have not yet fertilized your tree, this would be a good time to feed. Just be careful not to use too much fertilizer. It would be better to use less now and re-apply some additional fertilizer is about a month or six weeks. Here's a link to more information on peach tree care: http://homeorchard.ucanr.edu/Fruits_&_Nuts/Peach/ which also applies to nectarine trees.
 
We hope that this information is helpful. You're welcome to contact us again if you have other questions.

Help Desk of the UC Master Gardener Program of Contra Costa County (TKL)

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Note:  UC Master Gardeners Program of Contra Costa's Help Desk is available almost year-round to answer your gardening questions.  Except for a few holidays (e.g., last 2 weeks December), we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 2380 Bisso Lane, Concord, CA 94520. We can also be reached via telephone:  (925) 608-6683, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/. MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog.