Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk with your question about your oak tree. First off, let me say that I am sorry about your oak tree. It does not look very healthy in the picture you provided. While it is common for live oaks to shed significant leaves in the spring, it sounds like you are seeing a more general decline over years which is likely due to other causes. I also should note that our advice is based solely on the picture, as opposed to the arborist who come to your house and personally reviewed the tree on-site. Their advice is likely to be more accurate. You mentioned that they want to treat the tree yearly with a fungicide. Did they actually diagnose a fungal disease?
These would be my concerns for your oak based on the information you provided:
You mention that your neighbor's driveway was put in a few years ago. I presume that is the driveway either in front or behind the tree in the pictures. Regardless, both driveways appear to be under the drip line of the tree. The drip line of a tree is the outermost circumference of the leaf canopy. This is where, in rain, water will drip from the leaves of the tree onto the ground. Oak trees are very susceptible to damage from root compaction and grading. Any construction that has occurred under the tree could result in the death of important roots and the subsequent impending death of the tree. The death of the tree under these circumstances may not be fast, it might take years. Below is a link to a graph with an algorithm to determine if your oak tree may have Sudden Oak Death. Notably, it mentions that you need to consider physical damage first. Depending on when this driveway was installed, this may be the most likely cause of the trees decline. http://ipm.ucanr.edu/PMG/PESTNOTES/pni7498-1c.html
- It is impossible to tell what kinds of plants were placed under the oak tree. The general rule for planting under oak trees is that plants should be quite a few feet from the trunk and that the understudy plants cannot require summer water. If these plants under the oak tree are being watered regularly, that can make the oak tree more susceptible to fungal diseases from the soil. Mature oak trees should not be watered during the summer at all. You should only water during the winter if there is insufficient rain (less than 20 inches/season).
- Lastly a fungal disease would be a possible cause for this kind of decline. There are a variety of fungal diseases that can affect oak trees, however, one of the most concerning is a fungal disease called Phytophthora ramorum. The common name for the disease it causes is Sudden Oak Death. This disease is typically spread from nearby infected California bay laurel trees, rhododendrons or camellias. The pathogen survives on the leaves of the bay laurel and is transmitted to nearby oaks by rain or wind. Once on the oak it infects the trunk and the tree can develop a canker where it bleeds a thick, sticky sap. There is a rapid browning (over 2-4 weeks) of the leaves, however, the tree has usually been infected for two years at that point. This disease is diagnosed by sampling the leaves of nearby host plants (usually a nearby bay laurel) or the bark. Bark sampling should be done by an expert. This disease does not have any cure. There is a fungicide (phosphonate, Agri-Fos) which is approved as a preventative treatment. This will not cure affected trees but will suppress disease progression in early cases. It is injected into the tree or sprayed on the trunk. While it appears you can purchase this product and apply it yourself, it requires special equipment to give the tree injections. You could spray the tree but would likely need special equipment to spray a tree of this size. Given those considerations, treatment is likely a job best left to the arborists. If you treat for fungal disease, and it is not a fungal disease, you may adversely affect the health of the soil under the tree. Fungicides are non-specific and using one may kill non-disease causing fungi that are normal components of soil. For this reason, it is best to get a diagnosis of this disease before starting expensive treatments. There is more information about this disease at the following link: http://ipm.ucanr.edu/PMG/PESTNOTES/pn74151.html
I hope this information proves helpful to you as you make decisions about this tree. Below is a link to a very extensive guide to diseases of oak trees which you may want to look through. http://www.suddenoakdeath.org/pdf/psw_gtr197.pdf
Best of luck with your oak tree. Please contact the Help Desk again if you have more questions.
Help Desk of the UC Master Gardener Program of Contra Costa County (SES)
Note: 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.
Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
I know in the future that we should try to pull the weeds before they flower, but I'm not sure how to proceed with the situation now. Based on my research, I was thinking of trying to hand-pull as many weeds as we could in the next few weeks. I was then going to solarize the area for 6-8 weeks with two layers of clear painter's plastic with PVC between them. First of all, do you think this is a good plan? Could solarizing the soil damage the tree roots? If for whatever reason you think this is not a good plan, please let me know what you suggest. I am open to herbicides if necessary. Although I like the idea of getting rid of the weeds this summer to plant when the rains start, I am open to a different plan that would manage the weeds better long-term. Thank you very much for your assistance!
Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk with questions about your parking strip in West County and how to deal with the weeds that have been there for quite a while. Pulling the weeds and then solarizing the soil would help kill the weeds, but it could harm the tree roots as you suspected, so it is not recommended.
A better idea is to pull as many weeds as you can, especially getting the roots out, and then sheet mulch the area. Sheet mulching is an excellent way to kill weeds and improve the soil at the same time. Water the area thoroughly and then lay down cardboard or burlap. The cardboard can be purchased in rolls or you can use recycled boxes. Just make sure to remove any tape or plastic labels. Overlap pieces 6 to 8 inches, completely covering the ground with no gaps. Keep all material away from the tree trunks, though. You'll need to leave 6 to 8 inches clear. You'll need to monitor these areas for weeds and remove them. Water the cardboard so it's evenly moist to keep it in place and make it more malleable.
On top of the cardboard, put a layer of compost about an inch thick. This will "jump start" the decomposition process. Then, on top of the compost apply a thicker layer of chipped plant material (often called “mulch”). This should be 3 to 5 inches thick. You can often get chipped plant material for free from tree companies, although they will often dump an entire truck load in the driveway and this may be too much for your project!
If you are thinking of installing drip irrigation in the parking strip, it should go on top of the cardboard and under the compost.
You should be able to do your fall planting using this sheet mulching method. Continue to water the area occasionally this summer to make sure it's ready for planting when you are.
After at least 10 years of weeds growing uncontrolled, you will have a large number of weed seeds in your soil. There's a saying: one year of seeds gives you 7 years of weeds. These seeds remain viable for a long -time so you need to continue to be vigilant. When you plant your new landscape, you'll expose the soil, giving the seeds a chance to sprout. You'll need to really watch for these and pull them before they can become established and certainly before they set seeds. You will also need to maintain the mulch layer, adding additional chips when you notice thin spots.
And be aware that you will probably see weeds growing in the mulch. Weed seeds can travel long distances and many will end up alighting on top of the mulch where they will sprout, but they'll be very easy to pull out if you don't let them gain a foothold.
These links are to more information and diagrams about sheet mulching, as well as one from Washington State University about using arborist chips:
http://sacmg.ucanr.edu/files/163135.pdf
http://ccmg.ucanr.edu/files/221117.pdf
http://cru.cahe.wsu.edu/CEPublications/FS160E/FS160E.pdf
I hope this information is helpful. Don't hesitate to contact us if you have more questions. And good luck with your project!
Help Desk of the UC Master Gardener Program of Contra Costa County (SHE)
Note: You can also subscribe to the Biog.ogram 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 Biog.
Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Help Desk Request: I'm delighted you're available to help diagnose garden problems! Below are four pictures of a grape leaf problem. I have four old vines - Flame and Thompson seedless - that grow against a south-facing solid fence. The vines are close enough that they are co-mingled across the fence. The problem currently is located in one area of the vines and was not visually noticeable three weeks ago. All the vines are vigorous and seem healthy except for the affected leaves. I have cut most of the leaves and vines that are visibly distressed and placed them in my green waste bin. In the 15+ years I've had the grapes I have never had this problem; however, this year I was VERY, VERY late in pruning back the vines, and did not complete the pruning until the new vines had grown a couple feet long. Perhaps the evil villain over-wintered because of my tardy pruning?
Any idea what the problem is - fungus, bug or insect critter, bacteria? I have not seen anything crawling on either side of the leaves. And, what is your recommended approach and treatment? Thanks in advance for your help!
Submitted Representative Images of Affected Grape Leaves (below)
MGCC Help Desk Response: Thank you for contacting the UC Master Gardener Help Desk with your issue of ‘bumps and holes' on your grape leaves.
Thank you for the pictures and note that the blister is on the top of the leaf and the bottom shows fuzzy white. We were able to diagnose simply from the damage itself. The bumps are the result of mites – specifically grape erineum mites. The good news here is that even though the mites infest the leaves, no management is necessary as they rarely lead to any crop losses.
Erinium mites are wormlike, light yellowish white and microscope so you really would need magnification to see the actual mites themselves.
Young leaves show bright pinkish or reddish swellings on upper surfaces. Corresponding areas on lower surfaces are concave and densely lined with a felty mass of plant hairs
The mites overwinter under outer bud scales and move to unfolding leaves in spring. They associate in small groups to feed on lower leaf surfaces; the result is production of masses of enlarged leaf hairs inside a blisterlike area on the leaf. On the undersides of the leaves, beneath the swellings, are concave, densely lined, felty masses of oversized leaf hairs in which the mite populations develop. As the population increases, some move to new areas or to other leaves. From mid-August to leaf drop, there is a movement back to the overwintering site underneath the bud scales.
You indicated that this is new to you and that you were a bit late pruning. I cannot explain for sure why this year and not prior years and I cannot be sure the late pruning added to this situation.
Following is a link to a UC Pest Management website on the subject but it does not really add to the information I have provided above. http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/PESTS/grerineummte.html
Good luck and enjoy those grapes, and do not hesitate to contact us again with garden problems.
Help Desk of the UC Master Gardener Program of Contra Costa County (EDC)
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 Biog.
Wisteria Vein Mosaic Virus
Advice from the Help Desk of the
UC Master Gardener Program of
Contra Costa County
Client's Question: This spring I planted 4 wisteria vines around our pergola and they've grown well but now two plants have bumpy leaves and one has brown curl at the end of a few leaves. I worked the soil well and added compost before planting. Any ideas? Thank you.
Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk regarding your wisteria plants. Your photos are very helpful in showing the damage you mentioned. You mentioned that one plant has a few leaves with brown tips and curling, and 2 plants have “bumpy” leaves.
On those “bumpy” leaves, I see some yellow patches, and my research leads me to believe it is Wisteria Vein Mosaic virus. This virus affects a wide variety of horticultural and vegetable crops — roses, beans, tobacco, tomatoes, potatoes, cucumbers and peppers — This Mosaic is a viral disease found throughout the United States.
The virus is transmitted mechanically and by grafting. Cuttings or divisions from infected plants will carry the virus. It can be introduced into landscapes on new plants that were infected during their production. Other wisteria can become infected if it comes into contact with infected sap from a plant with the virus. For example, using the same tool for infected and non-infected plant without disinfecting in between use. Mosaic virus over winters on perennial plants and is spread by insects that feed on them. Aphids, leafhoppers, whiteflies and cucumber beetles are common garden pests that can transmit this disease. Soil, seed, starter pots and containers can be infected and pass the virus to the plant.
Once a plant becomes infected with the virus, it usually remains infected throughout its life.
Aside from discoloring foliage and distorted leaves, the virus does not seriously harm wisteria or significantly reduce the vigor of infected plants. There is no cure or treatment, and generally none is needed if the plant's cultural needs are met and it is otherwise healthy.
Here are a few precautions to take:
- Do NOT save seed from infected crops.
- The virus can be spread through human activity, tools and equipment. Frequently wash your hands and disinfect garden tools, stakes, ties, pots, greenhouse benches, etc.
- Avoid working in the garden during damp conditions (viruses are easily spread when plants are wet).
Here is a reference link from UC on the virus. Take a look at the photo attached to the article, it looks very similar to your photos. http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/DISEASES/wisteriavirus.html
If you are interested, here is an article describing first report of Wisteria vein mosaic virus in Wisteria sinensis in the United States of America. https://www.plantmanagementnetwork.org/pub/php/brief/2008/wisteria/
Plant virus symptoms look similar to many nutrient deficiencies. The following conditions will also cause the brown tips and curling leaves that you see:
- Too much fertilizer/salt in the soil.
- Soil too wet and/or poor drainage.
- Other nutritional deficiencies.
You mentioned that you planted 4 plants and only one has brown tips. Take a look to see if that plant receives more sun than the others which might explain the brown tips.
Here is a reference on how to manage pests in wisteria. I recommend reading the articles under Environmental Disorders (on the right side of the screen), and there is also information on good cultural practices. http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/wisteria.html
It is difficult to say whether the Mosaic virus is the cause of both the “bumpy” leaves and the brown tips and curling leaves or they are also caused by cultural practices (e.g. excess fertilization/salt, overwatering).
Since your plants are new and only planted in the spring, it is possible that the plants were already infected with the virus when you bought them. You might want to talk to the nursery and see if they would replace them.
I hope this information is helpful in managing your wisteria. I have a wisteria myself and it is such a joy to see the flowers in the spring. Please do not hesitate to contact us if you have further questions.
Help Desk of the UC Master Gardener Program of Contra Costa County (BY)
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 Biog.
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.
http://www.crfg.org/pubs/ff/persimmon.html
and
http://sonomamg.ucanr.edu/The_Kitchen_Garden/FRUITS/Persimmon/
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: 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 Biog.