- Author: Help Desk Team
Now that the leaves have fallen, or mostly fallen, from your backyard fruit trees, are you wondering whether you should apply dormant sprays?
“Dormant sprays” or “delayed dormant sprays” are terms used for the application of pesticides when the tree is dormant or just coming into bud swell. The pesticide could be a fungicide used to help manage fungal disease or a horticultural oil or oil in combination with insecticides to kill insects.
Don't assume that you need dormant spray. Before reaching for the spray, first determine whether your trees have previously had a disease or serious insect pest problem that can be managed with dormant sprays. Have you already tried all non-chemical recommendations for lessening the problem? Finally, evaluate the amount of damage from the disease or insect pest you experienced in the prior growing season to decide whether a pesticide is really needed.
Fruit tree diseases that can be managed by applying a fungicide dormant spray include peach leaf curl, brown rot, and shot hole disease.
Peach leaf curl affects only peach and nectarine trees. It shows up in spring after the tree has leafed out. Leaves are thickened, curled, and colored red or yellow instead of normal green.
If your tree has had significant peach leaf curl in prior years, dormant spraying with a fixed copper spray just after all the leaves have fallen from the tree (usually December to January in our County) may prevent or reduce the severity of the disease. For information on managing peach leaf curl, see https://ipm.ucanr.edu/PMG/PESTNOTES/pn7426.html/
Brown rot (Monilinia) is a fungal disease that can affect peaches, plum, cherries, apricots, and nectarines. In the spring blossoms on infected trees shrivel and die, often clinging to the twigs. Leaves at the base of infected twigs may also turn brown and die. Fungal spores attach themselves to developing fruit and show up as brown or tan spots on the surface of the fruit.
If your trees had significant fruit loss from brown rot in the prior growing season, a dormant spray of a copper-based fungicide may help. Apply it at the pink bud stage while flower buds are still tightly curled and pink in color. For more information on brown rot, see http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/DISEASE/aprbrownrot.html.
Shot hole (coryneum blight) can affect plums, nectarines, peaches, cherries, and especially apricots. It shows up as small reddish holes on leaf surfaces. Often the holes turn brown and drop out. Fruits may also be infected. Where disease has been severe and cultural steps haven't helped, a fungicide spray following complete leaf drop may be needed. See http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/DISEASE/shothole.html.
Insects that can be managed with dormant sprays of horticultural oils or oils mixed with insecticides include scale, aphids and spider mites. Don't spray unless you have confirmed that the insects are present in damaging numbers and cannot be controlled by other means. Keep in mind that spraying may also kill beneficial insects which are the first line of defense against insect pests. More information on controlling these insect pests can be found at these UC websites: http://ipm.ucanr.edu/QT/scalescard.html, http://ipm.ucanr.edu/QT/aphidscard.html and http://ipm.ucanr.edu/QT/spidermitescard.html.
Before spraying, read and carefully follow the label instructions on the pesticides you use, including wearing recommended protective gear.
If you want to add another fruit tree to your home orchard, stay tuned for an upcoming Blog article on Selecting and Planting Bare Root Fruit Trees to be published in December. If you want to be sure you can get a specific variety of fruit tree, contact your local nursery. The nursery may be able to reserve it for you, or if necessary, special order it for you.
Help Desk of the UC Master Gardener Program of Contra Costa County (TKL)
Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
MGCC Help Desk Request: What's going on with my persimmon tree? I worked a bunch of compost into the soil around it in the spring and mulched with leaves. But it looks like it needs nutrients. What should I give it? This is its third year since planting. Thanks
Persimmons are generally disease free, but the black spots showing on some of the leaves look like fungal spots. I can't tell from the photo what type of fungus, but there are several that can occasionally affect persimmons. A wet spring, such as we have had, may exacerbate this, as can overhead watering, so you should make sure any nearby sprinklers do not hit the tree. UC does not recommend any treatment other than good cultural care. Removing any fallen leaves also will help. http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/DISEASES/leafspotdis.html.
As long as the spotted leaves are green, I think it would be best to leave them on the tree, as the foliage looks a little sparse - those leaves are still making food for the tree. Now we have hotter and dry weather, leaf spot fungi will be less active.
As you mention, the tree does look like it could use a little help. Persimmons don't generally need a lot of fertilizer, but yours may benefit from a balanced fertilizer for fruit trees (follow package directions ). Make sure the mulch does not cover the bottom of the trunk just above the roots - this area should be clear so that air can get to the roots. When adding compost to the tree you do not need to work it into the soil, which may risk damaging the roots. Worms and other soil creatures will take care of incorporating the compost. Persimmons don't need as much water as some other fruit trees, however, a young tree needs regular irrigation until established, and will do better later on with continued irrigation. The soil should not be overly wet, but do not let it dry out.
The following links give more information about caring for persimmons.
I hope this information will help your tree to do better, and if you have any further questions, please do not hesitate to contact us.
Help Desk of the UC Master Gardener Program of Contra Costa County (SMW)
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: email@example.com, 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 Biog.
Home Gardening Advice from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Client's Request (from previous phone conversation): I've just moved into my new house. There's a small “fruit tree orchard” in the back garden. I'm not acquainted with growing fruit trees, but my neighbor tells me that the previous owner pruned them this time of year. Can you give me some advice on what and where to prune the trees.
MGCC Help Desk Response: Thank you for contacting the UC Master Gardener Program's Help Desk.
You may be interested in a free Master Gardener library talk about growing apples and pears on Feb. 28 at the Lafayette Library from 6-8 pm. I am sure pruning will come up during that talk. To RSVP or to ask about upcoming talks contact firstname.lastname@example.org.
Since you are beginning on your newly acquired "home orchard" and you have several different types of fruit trees, below are a number of links from UC that you might consult for both general and specific information on tree pruning.
General and Specific Information for the Home Orchard, including pest control and pruning, please see: http://homeorchard.ucanr.edu/. This one reference will probably cover most of your concerns.
Vine (e.g. grape) Pruning: http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/ENVIRON/trainprune.html
Good luck on your home orchard.
Thank you for contacting us. Let us know if we can be of further service.
Help Desk of the UC Master Gardener Program of Contra Costa County
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925) 646-6586, email: email@example.com, 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 (http://ucanr.edu/blogs/CCMGBlog/).
Advice for the Home Gardener from the Contra Costa Master Gardener Help Desk
Client's Questions and Requests
Client called and discussed about his need for more information about pruning his numerous backyard fruit trees. He lives in central county. CCMG Help Desk followed up with an email on advice about pruning his fruit trees.
CCMG Help Desk Response and Advice:
Thank you for calling the Master Gardener help desk this morning. It was nice to speak with you. It was also great to get a new recipe for cooking fava beans!
You have a wide variety of wonderful fruit trees in your yard, many of them not commonly planted in this area. You asked about pruning them. Basically, the idea behind pruning is to control size for easier care in maintaining and picking fruit (taller trees do not bear more fruit!); increase strength – develop strong limb structure; distribute sunlight evenly throughout tree; regulate fruit bearing – removes excess fruitwood; renew fruitwood – to continue strong buds and flowers; and to remove undesirable wood- dead, broken, and crossing branches.
University of California and its Cooperative Extension provides a wealth of information, most of it free through their catalog (http://ucanr.edu/Publications_524/)which you can order from (see also link on CCMG home page (http://ccmg.ucanr.edu/), column left). You can also find extensive UCCE information published on the web. Here is a link to a great publication that describes fruit tree pruning and includes diagrams to help you figure out how to prune your own trees: http://homeorchard.ucdavis.edu/8057.pdf.
You mentioned that some of your trees were getting large-here's a link to an article about pruning overgrown fruit trees: http://homeorchard.ucdavis.edu/8058.pdf. Both of these have enough basic information to cover all your deciduous trees, but for the less-common varieties, I'll give you some hopefully useful hints and tips below, as well as links to more information about each one.
Prune citrus in late spring or summer to shape trees, only to remove twiggy growth, dead wood and weak branches, or any crossing, broken or shaded branches from the interior. Wait until May to prune out any frost-damaged wood, as it may revive. Here is a link to Citrus for the Home Garden in Contra Costa County: http://ucanr.edu/blogs/slomggarden/blogfiles/4260.pdf. You'll find lots of information specific to growing citrus here. Here is another link that covers diseases and disorders of citrus fruit: http://www.ipm.ucdavis.edu/PMG/C107/m107bpfruitdis.html. You'll see that brown rot is common in citrus—this causes the soft dark decay that develops in citrus and occurs mostly on the bottom side of fruit and happens mostly to fruit lower on the tree (closer to the soil). The dark spots on your Mandarins is possibly from a bacterial infection.
Codling moths (common on apples, pears and other fruit) can be a problem for quince. They can be difficult to manage, especially if the population has been allowed to build up over a season or two. It is much easier to keep moth numbers low from the start than to suppress a well-established population. In trees with low levels, codling moth often can be kept to tolerable levels by using a combination of nonchemical management methods; however, it is important to begin implementing these measures early in the season. Sanitation should be the first step in any codling moth control program. Every week or two, beginning about six to eight weeks after bloom, check fruit on trees for signs of damage. Remove and destroy any infested fruit showing the frass-filled holes. It also is important to clean up dropped fruit as soon as possible after they fall, because dropped fruit can have larvae in them. Removing infested fruit from the tree and promptly pick up dropped fruit from the ground is most critical in May and June but should continue throughout the season.
Excellent control can be achieved by enclosing young fruit in bags right on the tree to protect them from the codling moth. This is the only nonchemical control method that is effective enough to be used alone and in higher population situations. However, it is quite time consuming to apply the bags, so this method is most manageable on smaller trees with fewer fruit. You can bag all the fruit on the tree or just as many fruit as you think you will need. Keep in mind that unbagged fruit are likely to serve as a host and increase the pest population, so it would be prudent to employ sanitation to keep the population in check.
Here is a link to information about codling moths from the University of California: http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7412.html that goes into detail about controlling these pests.
Prune in late winter after danger from winter freezes, but before the tree blooms in spring. To keep the interior of the tree open during the growing season, prune in summer as needed. Light annual pruning of established trees encourages fruit production; pomegranates tend not to require heavy pruning if maintained regularly. Remove dead and damaged wood during late winter and remove sprouts and suckers as they appear. Heavy pruning will reduce the crop.
As I mentioned on the phone, apricots should be pruned during the summer in late August because of a fungus that infects trees during the cool and wet season. Remove shoots from the center of the tree and cut out interfering limbs and dead and diseased wood. Here is a link to information about pruning apricots:
Fig trees are productive with or without heavy pruning. It is essential only during the initial years. Since the crop is borne on terminals of previous year's wood, once the tree form is established, avoid heavy winter pruning, which causes loss of the following year's crop. It is better to prune immediately after the main crop is harvested, or with late-ripening cultivars, summer prune half the branches and prune the remainder the following summer. If radical pruning is done, whitewash the entire tree. Here is a link to information from California Rare Fruit Growers (CRFG): http://www.crfg.org/pubs/ff/fig.html.
Prune persimmon trees to develop a strong framework of main branches while the tree is young. Otherwise the fruit, which is borne at the tips of the branches, may be too heavy and cause breakage. A regular program of removal of some new growth and heading others each year will improve structure and reduce alternate bearing. An open vase system is probably best. Even though the trees grow well on their own, persimmons can be pruned heavily as a hedge, as a screen, or to control size. They even make a nice espalier. Cut young trees back to 1/2 high (or about 3 feet) at the time of planting. Here is information from CRFG: http://www.crfg.org/pubs/ff/persimmon.html and from UC that includes information on pests and diseases of persimmons: http://www.ipm.ucdavis.edu/PMG/GARDEN/PLANTS/persimmon.html.
Since so many of your trees are not typically grown in our area, one of your best resources is the California Rare Fruit Growers. Their website is http://www.crfg.org/, the local chapter is the Golden Gate chapter (http://www.crfg.org/chapters/golden_gate/index.htm). The Golden Gate Chapter of CRFG conducts meetings throughout the northern San Francisco Bay Area, usually in the odd-numbered months on the second Saturday of the month. Meetings almost always include speakers, tastings, a raffle of unusual plants and the chance to talk to people who live in your area and who share your interests. You would probably find someone who could advise you further on pruning techniques at one of their meetings. In addition, CRFG holds a Scion Exchange in January that you might want to attend. In the past when I've attended, they had classes on pruning of the various fruit trees that you have, let alone the opportunity to get scions that you might want to graft onto your trees (scions are usually free… $5 charge for non-members at the door). Information on the CRFG's Scion Exchange can be found at http://www.crfg.org/chapters/golden_gate/scionex.htm. I have always enjoyed the Exchanges when I attended.
I hope this gives you a start on pruning your backyard orchard. Please let us know if you have more questions.
Contra Costa Master Gardeners Help Desk
Note: The Contra Costa Master Gardener Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925) 646-6586, email: firstname.lastname@example.org, or on the web at http://ccmg.ucanr.edu/Ask_Us/