- Author: Help Desk Team
Prune Apricot and Cherry Trees in August
If you have apricot, cherry, or related hybrid tree varieties such as aprium and pluot in your yard, plan to prune them before the end of August. This timing will help prevent infection by a deadly fungal disease called Eutypa Dieback that can kill these trees as well as grape vines.
When infected by Eutypa, branches or entire trees wilt and die suddenly, often with the leaves still attached.
Apricot tree with branch killed by Eutypa
Signs that your tree may be infected by Eutypa include darkly discolored cankers on the branches and oozing of amber colored gummy sap.
Eutypa cankers on apricot branch
Oozing Sap on Cherry Tree from Eutypa Infection
[Editorial Note: apricot photos downloaded from UC Repository. Cherry tree photocopied from UC ANR blog article by Chuck Ingels, UCCE Sacramento, https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=16014 ]
Many other varieties of trees and shrubs can become infected with the Eutypa fungus without showing disease symptoms or progressing to the dieback stage. These other tree and shrub varieties can serve as store houses for the Eutypa pathogens that could potentially spread to your grape vines and apricot, cherry, aprium and pluot trees. Trees and shrubs that can serve as reservoirs for the disease include almond, apple, blueberry, crabapple, honeysuckle, kiwi, oleander, pear, and certain native plants such as big leaf maple, California buckeye, ceanothus, and willow.
Eutypa disease is spread from an infected tree, shrub or vine to uninfected trees by splashing water from sprinklers or rain. The splashing water allows the fungal spores to enter through pruning or other wounds. Pruning vulnerable tree varieties by the end of August allows pruning wounds to heal and close before the typical start of the rainy season in Contra Costa County in late October. Also, avoid using sprinklers near recently pruned trees since water from sprinklers can also spread infections. Using these precautions will reduce the risk of infection for your trees.
Studies have shown that the Eutypa pathogens can also be spread on pruning tools that have been used to prune infected trees and shrubs. To prevent such transmission, be sure to disinfect your pruning tools before and after pruning.
To disinfect tools, soak them for thirty minutes in a 10% bleach solution (nine parts water to one part bleach). Bleach is corrosive so be sure to rinse the tools thoroughly with water after soaking. Then oil them. The bleach solution loses 50% of its effectiveness after two hours, so be sure to use a freshly mixed batch.
As an alternative to bleach, you can disinfect pruning tools with 70% isopropyl alcohol. Just spray it on your tools and it will kill any pathogens almost immediately. Alcohol is not corrosive, so you don't need to rinse it off tools.
An internet search for “how to prune apricot [or cherry, aprium or pluot] trees” will help you find videos that demonstrate good pruning techniques. Just be aware that most pruning videos are filmed when the trees are dormant. With no leaves, the branches can be more easily shown in the video to demonstrate pruning techniques. In California, you don't want to wait until the dormant season to prune these vulnerable trees because that increases the risk of an Eutypa infection. So, you'll need to adapt the pruning techniques to a tree that still has leaves.
For more information on Eutypa disease, visit this University of California IPM website: http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/DISEASE/eutypadieback.html
Fertilizing Fruit Trees and Information on Chill Hours"
Advice for the Home Gardener from the
Help Desk of the UC Master Gardeners of
Contra Costa County
Home Gardener Request: We're finally jumping into fully caring for our mini-orchard here in Mid-County. Could you please point us to a good reference book for that task... Also, we are getting acquainted with chill hours for growing and/or buying various fruit trees, especially for apple, plum and pear trees. Where can we find local info on chill hours?
CCMG Help Desk Response: Thanks for calling the UC Master Gardener Program Help Desk this morning with your questions about what and how to feed your apple, plum and pear trees and year to date chill hours for your area.
After some further thought, I'd like to suggest that you may want to complete a soil test of your orchard to see what your soil may be lacking before fertilizing your trees this spring as that will drive what and how much to feed.
I found that the UC Home Orchard: Growing Your Own Deciduous Fruit and Nut Trees book supports soil testing before adding potentially unnecessary fertilizers to your soil:
Although deciduous fruit trees require many nutrients for tree growth and fruit production, those grown in backyard settings in typical sandy loam to clay loam soils with proper irrigation rarely need to be fertilized. Nutrient deficiencies, when encountered, are generally limited to nitrogen, potassium, iron, and zinc, and on rare occasions, boron. Unless your soil has a known nutrient deficiency, regular applications of fertilizer usually are not necessary in a mature orchard.
Below is a link to a list of soil testing companies for you to choose from. When you contact one of the labs, they will give you instructions on how to take the sample and prepare it for shipping. Some of the labs listed also have helpful information on how to interpret the results including the amounts of necessary additives your soil needs. Soil testing companies: https://ucanr.edu/sites/ccmg/files/51308.pdf
Below is a link to information from the UC California Backyard Orchard website. It includes information on common elements for normal growth and amounts to feed by age of the tree rather than size: http://homeorchard.ucanr.edu/The_Big_Picture/Fertilization/
The links below include helpful seasonal information for growing fruit trees:
Apples & Pears: Calendar of Operations for Home Gardeners: http://homeorchard.ucdavis.edu/7258.pdf
Plums: Calendar of Operations for Home Gardeners: http://homeorchard.ucdavis.edu/7262.pdf
And finally, here is the link I used to find current information on chill hours in Contra Costa County. I selected the El Cerrito Weather Station for a chill hour to date and historical information:
https://ucanr.edu/chillcalc/?controller=station&action=reportresults&STATION=213
You may want to consider purchasing The UC Home Orchard: Growing Your Own Deciduous Fruit and Nut Trees book as it was developed especially for backyard orchardists, rare fruit growers, and small-scale growers. It is available through various online booksellers and through the UCANR Catalog: https://anrcatalog.ucanr.edu/
I hope you find this information helpful. Please let us know if you have any additional questions.
Help Desk of the UC Master Gardener Program of Contra Costa County (SLH)
Notes: Contra Costa MG'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.edu/HortCoCo/ You can also subscribe to the Biog.
Advice for the Home Gardener from the Help Desk of the UC Master Gardener Program of Contra Costa County
Help Desk: Thank you for contacting the UC Master Gardener Program Help Desk with your concerns about your ailing Italian Cypress trees in Central County.
Italian cypress Cupressus sempervirens thrive in full sun in the dry, Mediterranean-type climate of California, but it does poorly and can become stressed and diseased in a wetter or cooler climate and if it is planted where it gets too much water or in partial shade or if it is exposed to cold winter temperatures. As we discussed on the phone, the very wet winter last year after years of drought may not have helped your trees.
Based on what was recommended to you by a tree service, they may have been attempting to treat for root rot. As its name implies, root rot happens when the tree's roots are too wet for extended periods, causing branches to wilt, turn yellow or brown and eventually die. A fungicide applied to the soil as directed might halt the rot. As discussed, this may or may not help your trees. There is more information on root rots in the included pest link below.
The irrigation requirement for Italian Cypress in at your garden in Central County is ‘Low Water', so your established trees would need no irrigation during the winter months, minimal irrigation in the Spring and Fall (no more than .5 gallons per month per tree) and 2 gallons per month total irrigation per tree in the hottest months of June – August. With this information you can calculate how long to run your drip irrigation depending on the drip emitter output you are using. Be careful not to overwater!
You may also want to do a close examination of your trees to help determine an appropriate course of action. I've attached information below on various pests and diseases of cypress trees: http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/cypress.html
Below are links to UC Pest Note information on several common pests of cypress that you'll want to look for:
Cypress tip miner—Argyresthia cupressella: Browning tips may be caused by cypress tip miners, the larvae of a tiny, silvery tan moth: Argyresthia cupressella. The females lay eggs on the green tips. The eggs hatch into larvae that feed on the twig tips. http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/INVERT/cyptipminer.html
Cypress canker -Seiridium cardinale: This fungus attacks trees in the cypress family by entering through cracks in their bark and producing toxins that wreak havoc with the flow of sap, limiting the supply of water and nutrients. The cracks in the bark could be caused by pruning cuts, boring insects, or weather damage. The spores spread by wind and water splash. Symptoms include dieback beginning from the top of the tree or branches browning and dying throughout the canopy. A branch can change color over a period of days. http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/DISEASES/cyprcanker.html
Spider mites: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7405.html
As we discussed, your trees should be provided with the best possible cultural care: full sunlight, good drainage, moderately fertile soil, and enough moisture to prevent summer drought stress to help them resist pests and diseases. UC does not have any specific recommendations about feeding programs for these trees, so our discussion about improving the soil around the trees with compost may be a better course of action rather than feeding with general fertilizers.
While we are unable to recommend a specific arborist in our area, we can refer you to the International Society of Arboriculture (ISA) ‘Find an Arborist' website. This website has a search feature that allows you to find certified arborists based on where you live. When you call, explain your situation and ask if they specialize in cypress problems. https://www.treesaregood.org/findanarborist
Please call us again if you wish to discuss more specifics.
Good luck with your trees.
Regards,
Help Desk of the UC Master Gardener Program of Contra Costa County (SLH)
Notes: Contra Costa MG'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.edu/HortCoCo/ You can also subscribe to the Biog.
Advice for the Home Gardener from the
Help Desk of the UC Master Gardener Program
of Contra Costa County
Request: We have lived in our house for 22 years in central County. Just the past few years we have been plagued by “no-see-ums” as the weather starts to warm. They are generally gone by the time it's hot.
Of course, the no-see-ums chase us indoors during the best time of year for gardening, socializing and enjoying the out-of-doors. Last year I spent time online researching how to prevent this pesky critter. I remember reading somewhere (?) a process for treating the yard to prevent their “hatch". Unfortunately, I can't find what I read, only how to prevent bites.
Can you help me with this? We have no lawn at the house, just trees and plants surrounded mostly by bark. I thought there was something you could spray or spread on the bark ground cover.
I will appreciate any advice you can share. Thank you in advance.
CCMG Help Desk Response: Thank you for contacting the UC Program Master Gardner Help Desk with your question concerning those pesky No-See-Ums you are battling. My childhood was spent in Vermont where these pesky flies breed in epic proportions in the summer, making life outdoors miserable. I sympathize with your frustration.
These minuscule flies are in the Ceratopogonidae family of flies commonly known as no-see-ums, also referred to as sand flies, gnats and biting midges. This family includes more than 5,000 species, distributed worldwide, with the exception being the Antarctic and the Arctic.
Like mosquitoes, No-See-Ums lay their eggs in moist areas. Both males and females consume nectar and other sweet juices for nourishment. Females, however, will also seek out a blood meal to fuel egg production. Female No-See-Ums will bite humans, pets, livestock, wild animals and birds. They breed and develop in moist wet areas. With her need for blood satisfied, the impregnated female will seek out an appropriate place to lay her eggs, which can include water-retaining hollows in trees, muddy water, wet sand, and other similar areas. About 28 days later, adult No-See-Ums emerge and the cycle begins again. No-See-Ums can be more difficult to get rid of than mosquitoes. They are smaller than mosquitoes and more agile fliers.
The research on control leans heavily to “exclusion” techniques as opposed to chemical treatment, misting and fogging. Chemical treatments have proven, in testing, to have little to no effect. If spraying or treating with chemicals is not effective there is little sense in spending your time and money in addition to adding the pollutant to your environment. While exclusion is the preferred control method you should look your property over and make sure you do not have “wet'” breeding sites.
Exclusion techniques appear to be the most effective method of control. These include wearing protective clothing, installing ultra-fine mesh screening (US 16 Standard Mesh) in-home screens and enclosing patio and porch areas with this same fine mesh screening. If you are really determined to be outside there are also pop-up tents designed with drop-down screening fine enough to block the No-See-Ums.
Topical sprays have proven to be only barely effective but might add a bit of protection while working in the garden. You could use a mosquito repellent with DEET, in addition to wearing protective clothing.
There is some information that refers to trapping as being moderately effective to highly effective, the trap tested is the CO2 mosquito trap. A home version is not too expensive and might be worth a try. No-See-Ums and mosquitos breed in the same conditions so you would be controlling any potential mosquito population as well, it might be a win-win.
The UC information on gnats was very limited. The Bug Squad from UC Davis provides some more detailed information at https://ucanr.edu/blogs/bugsquad/index.cfm?tagname=Valley%20Black%20Gnats. The best information I found was a link to research-based information from the University of Arizona. https://cals.arizona.edu/apmc/docs/No-See-Ums-IPMShort.pdf
I hope you will find some success by employing these methods. The best method may be the passage of time and the increase in temperature.
Please do not hesitate to call us with more questions …hopefully we will find some new information on the control of No-See-Ums.
Help Desk of the UC Program of Master Gardeners of Contra Costa County (BHD)
Notes: Contra Costa MG'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.edu/HortCoCo/ You can also subscribe to the Biog.
Advice for the Home Gardener from the
Help Desk of the UC Master Gardener Program
of Contra Costa County
Subject: Grapefruit Tree vs Woodpecker
Cllient's Request: How can we keep a woodpecker(s) from making holes in the tree bark? We don't have any insects/ants on the tree bark and we're concerned that the damage will make the tree susceptible to disease. Thank you.
MGCC Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk with a question about woodpeckers on your grapefruit tree. From our phone conversation this morning, I identified the culprits as sapsuckers. These drill a series of holes, usually in straight horizontal lines, in live trees so plant sap oozes out of the holes. Sapsuckers feed on the sap, as well as on any insects that become trapped in the sap. Most of the time, sapsucker holes do not cause problems for the tree. When there is continuous sapsucker activity that increases the lines of holes to a significant percentage of the tree's trunk area, it can weaken the tree and potentially kill it.
Physical exclusion is the best way to prevent any kind of woodpecker damage. There are several methods you might see mentioned to prevent such as frightening devices or repellents, but these are not typically successful as birds quickly become accustomed to the deterrent. Covering the trunk with something that will prevent access to the tree bark is the best way to get sapsuckers to move on. Sections of lightweight sheet metal or roof flashing are fairly easy to shape around the trunk. You can get rolls of aluminum flashing at home improvement stores. Heavyweight plastic material can also be used. Use duct tape to hold it in place. You can also use wire mesh such as chicken wire, especially if it's bunched up somewhat. You will probably need to cover a great deal of the tree's bark to prevent the birds from just moving to an uncovered area. Whatever you use to cover the bark, make sure it is not too tight--you want to leave room for the tree to grow--and remove it when the birds have moved on. Depending on the size of the tree, you could also cover the entire tree with bird netting that you securely attach around the low base of the trunk to prevent all access to the tree.
Woodpeckers drill holes in trees for a variety of reasons. The largest holes are drilled for nest construction, usually in dead trees. Acorn woodpeckers drill 1/2 inch holes in which they store acorns. Smaller random holes are those made while looking for food. Woodpeckers' sharply pointed beaks and long tongues are used for extracting larvae and other insects from wood crevices. This can actually alert you to burrowing insects damaging a tree.
This link is to more information from the University of California about managing woodpeckers: http://ipm.ucanr.edu/PMG/PESTNOTES/pn74124.html.
I hope this information is helpful. Please don't hesitate to contact us again if you have more questions.
Help Desk of the UC Master Gardener Program of Contra Costa County (SEH)
Notes: Contra Costa MG'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.edu/HortCoCo/ You can also subscribe to the Biog.