Advice for Home Gardeners from the Help Desk of the
UC Master Gardener Program of Contra Costa County
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)
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: firstname.lastname@example.org, 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.
Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Client's Request: Thank you for calling the UC Master Gardener Program Help Desk this morning with a question about your young peach tree.
You have a young tree, planted bare root into a pot in January 2018, and then transplanted directly into the garden in the late spring / early summer when you were able to do so. You planted several fruit trees at the same time, and all were planted initially into pots and then into the garden, in roughly similar locations, with good drainage in the garden. All of the trees have been similarly irrigated. All of the trees are doing well with the exception of the peach. The peach had curling leaves last year (every single leaf appeared wilted) and you would like to prevent this, this year. You are wondering whether this is “peach leaf curl” or something else, and whether or not to presume it was peach leaf curl and to spray now.
If, after looking at these images, you decide that your leaves looked like this, then I would proceed as recommended in the UC Pest Note linked above.
If you do not think that your leaves looked like this, then we need to consider other possibilities. Wilted leaves can be evidence of a water transport problem in the plant. In this case, something in the vascular system isn't working as it should.
Beginning with the transplant from pot to garden last year, is it possible that the root ball was damaged? Or that there were air pockets in the garden created during transplant, causing some of the roots to dry out? Or that moles, squirrels or other garden visitors have created air pockets near the roots? If you think this is possible then I would dig down and fill those pockets with a wet-soil-sludge mixture to fill them in.
Is it possible that you have overwatered or that the drainage isn't quite as good as you had thought? Good drainage is one of the most important factors in siting fruit trees. Excess water in the root zone will produce a similar-looking result in the plant to a lack of water, since the roots will rot and cannot perform their intended function. In this case be cautious this spring with watering. Once the rains stop and you begin watering again, use a moisture meter or dig down 4 to 6 inches, and learn about your soil. Or perhaps you didn't water enough? Young trees are particularly susceptible to roots drying out. This link discusses irrigation of fruit trees:
Young trees have undeveloped root systems that are not very extensive. Because of this, your young trees need consistent moisture levels in their root zone in order to thrive. The "goldilocks" amount: not too much, not too little.
Some peaches are susceptible to root-feeding nematodes. Nematodes are tiny, eel-like roundworms. The species that attack plants are usually too small to be seen without a microscope, a soil test will be required. Here is a link to our local ist of soil testing labs for home gardeners. (http://ccmg.ucanr.edu/files/51308.pdf) Different labs perform different tests at different costs. I suggest that you call all or some of the labs to find out if they test for root feeding nematodes, whether or not the tests can provide definitive results, and the costs.
Inadequate nutrition from the soil can also result in discolored and crinkly leaves, look at the pictures at this link:
The soil test can also provide information about the nutrition available in your garden soil, if you request this.
You mentioned that you purchased the tree from a local nursery. Although a few local nurseries (usually bigger stand-alone ones) also are a grower for some species, they do not grow their own fruit trees, they rather purchase them (this year, last year, and many years prior) from a grower specializing in fruit trees, often in the Central Valley or lately for citrus in the Monterey Bay area. You might take a look at one of the various grower nursery websites and look up the particular variety of peach that you purchased to find out what you can learn. Most of the nursery grown fruit trees are grafted on root stocks. Some rootstocks are resistant to root-feeding nematodes. It might be helpful to know whether you have a more susceptible tree by identifying the rootstock which can often be found in the grower's catalogue or web site..
Overall, this link will give you valuable information on planting, care, and irrigation of young trees. http://homeorchard.ucdavis.edu/8048.pdf
Good luck with sorting this out and please contact us if we can help further.
Help Desk of the UC Master Gardener Program of Contra Costa County (MCW)
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.ignore.edu/HortCoCo/ You can also subscribe to the Blog.
Advice from the Help Desk of the
UC Master Gardener Program of Contra Costa
Client: I have 5 different varieties of nectarine and peach trees in my Central CCC backyard. I treat the trees in late winter for peach leaf curl using an organic - approved spray. That works great.
What do you think the problem is? What is the cure? I prefer to use organic methods.
Advice from the MGCC's Help Desk: Thanks for contacting the MGCC Program's Help Desk. From your description, the problem with your nectarine fruit appears to be caused by the “brown rot fungus”, monilinia fruiticola. Peaches can be attacked by Brown Rot as well.
Brown rot fungus is tough and can survive over the winter:
- in infected twigs
- inside dead blighted blossoms that remain on the tree
- dry mummified fruit that has been left on the tree from the previous year
- dry mummified fruit left on the ground from the previous year
Brown rot infection and disease development can take place over a wide temperature range and flowers can be infected from the time buds open until petals fall. Water must be present on the flower surface for infection to occur. Spores produced on the tree parts described above in spring are carried through the air by wind and splashing water to infect flowers of the new year's crop.
Appropriate applications of fungicide is the usual preventive measure to prevent brown rot, especially if you've had it occur before. However, fungicides can only prevent brown rot; they will not cure brown rot so timely application is important. Organic fungicides do not appear to be readily available for home gardeners. Recommended applications of copper-containing fungicides or synthetic fungicides such as myclobutanil at pink bud stage - just before the buds open can help avoid serious fruit losses. Rainy periods will require more spray. Additional applications when fruit starts to color may be needed if rainy weather persists. Do not apply copper compounds after bloom.
More specific information can be found by following the links below:
Good luck this year with your nectarines. Hopefully, pruning, sanitation, cultural care, and a timely application of a fungicide will minimize brown rot.
Please let us know if you have any further questions we can help you with, and thank you for contacting our program!
Help Desk of the UC Master Gardener Program of Contra Costa (JMA)
Note: The UC Master Gardeners 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: firstname.lastname@example.org, 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 From the Help Desk of the UC Master Gardeners of Contra Costa County
Client's Question: Last spring when my peach tree leafed out the leaves were all funny shaped. Can you tell me what the problem is and how to prevent it from happening again?
Symptoms Appear in Spring:Peach leaf curl first appears in spring as reddish areas on developing leaves. These areas become thickened and puckered, causing leaves to curl and severely distort. Later, affected leaves turn yellow or brown and can remain on the tree or may fall off. They are usually replaced by a second set of leaves that develop normally unless wet weather continues. The loss of leaves and producing new leaves results in decreased growth and fruit production and may expose branches to sunburn.
Peach Leaf Curl Prevention: Preventing peach leaf curl is relatively easy. You must spray peach and nectarine trees with a fungicide during the dormant season every year after leaves have fallen. A single early treatment when the tree is dormant is generally effective. However, with a particularly wet winter or spring, it may be advisable to apply a second spray late in the dormant season, preferably as flower buds begin to swell, but before green leaf tips are first visible.
Types of Preventives:The most commonly used, safest, and effective fungicides available to home owners are “fixed copper products”, but there are other products available as described in the University of California publication on controlling peach leaf curl. This free publication is available on the web at: http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7426.html.
Thorough coverage by the spray is the key. In any case, if leaf curl symptoms occurred on your trees last spring, be sure to treat now to prevent more serious losses the following year.
For More Information:You can find more information on growing peaches on UC's Home Orchard web site at: http://homeorchard.ucanr.edu/Fruits_&_Nuts/Peach/
Editor's Note: This is an updated version of an article originally written by MGCC and published in the Contra Costa Times December 4, 2010.
Help Desk of the UC Master Gardeners of Contra Costa County
Note: The UC Master Gardeners 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/blogcore/blogroll.cfm)./span>/span>