Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
MGCC's Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk with a question about your elm tree. Thanks also for sending good photos of the leaves, and especially of the insect. The insect is an elm leaf beetle, and it chews small round holes in elm leaves. A heavy infestation of the beetles can actually defoliate a tree, and multiple years of this will weaken the tree and cause its decline.
Managing elm leaf beetles will require an integrated program that includes good cultural care, conservation of natural enemies, regular monitoring, and possibly insecticides and bark banding by a licensed tree care company.
Cultural care: Elm trees are native to areas with summer rainfall, so you will need to give them adequate irrigation during our dry months. Pruning should be done just to remove dead branches. Avoid unnecessary pruning.
Preserving natural predators: Predators of elm leaf beetles include earwigs, lacewing larvae, some ground beetles and several others. To preserve these in your landscape, minimize pesticide application on surrounding areas and use less-persistent products, or apply pesticides in a band on the trunk (this will kill larvae when they crawl down the tree to pupate, thus reducing next year's problem). Bark banding, while it can be effective, may require application by a licensed pest control operator because the chemicals are not available for home use. Short-lived contact sprays of oils such as Neem oil or horticultural oil, or Spinosad can work, but only if the tree can be thoroughly sprayed, which is unlikely in a tree as large as yours.
Systemic insecticides can also be used for control of elm leaf beetles. These are applied to one area of the tree (bark, roots, etc.) and are moved to other parts of the tree (leaves). These pesticides when injected into the tree, or into the soil, minimize environmental contamination. Because elms flower before leaves come out, and are wind pollinated, the risk of harming beneficial pollinator insects is low when using a systemic insecticide on elms.
This link will take you to more information about elm leaf beetles: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7403.html.
There are other things that can cause problems for elm trees. The dead and dying branches at the top of the tree may be from a lack of water, but could be from a disease such as verticillium wilt which typically shows with dying branches at the top of the tree. Keeping your tree happy with adequate irrigation is probably the best thing you can do. For more information on elm tree pests and diseases see: http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/elm.html.
I don't know specifically how large your tree is (e.g., width), but it can take up to 200 gallons of water a week appropriately applied to keep a large elm healthy. Elms are listed as needing moderate water (in a range of very low to high). To calculate how much water you should be applying each month, go to this website: http://www.waterwonk.us/how-much/ where you can input the size of the tree (and that is how wide do the branches spread tip-to-tip) and the month. It will calculate the amount of water needed for optimal care.
Please let us know if you have more questions.
Good luck!
Help Desk of the UC Master Gardener Program of Contra Costa County (SEH)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer our 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, although we will be moving this spring. We will notify you if/when that occurs. We can also be reached via telephone: (925)646-6586, 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 (http://ucanr.edu/blogs/CCMGBlog/)
Help for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
MGCC Help Desk Response (via email): Thank you for calling the UC Master Gardener Program Help Desk with questions about your roses with (probably) Black Spot (Diplocarpon rosae) and/or Powdery Mildew [Podosphaera (previously Sphaerotheca) pannosa var. rosae].
Without the roses in-hand or recent photos, we can't be sure that the problem is appropriately identified. However, both of these diseases are common rose problem this time of the year and can be confirmed by pictures in the linked references below.
Both of these are fungal diseases. Both may be the result of the uneven weather we have been having with rain and warmth and cool weather all at almost the same time.
As we previously discussed, the initial treatments for the two are somewhat contradictory. Black Spot results from water sitting on the leaves. To avoid Black Spot, the leaves should be kept as dry as possible with no more than seven hours of moisture on the leaves. Powdery Mildew can be treated by washing off the leaves. The compromise would be to wash the leaves off during a warm period (say by 10am) to ensure that the water evaporates quickly. Also make sure that any fallen leaves are cleaned up from below the plants and disposed of into your garbage not into your compost. See the Pest Note link following : “Powdery Mildew on Ornamentals” for more details on management. http://ipm.ucanr.edu/PMG/PESTNOTES/pn7463.html.
Thank you for contacting Master Gardeners with your questions. Please do not hesitate to call again.
Help Desk of the UC Master Gardener Program of Contra Costa County (ECS)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer our 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, although we will be moving this spring. We will notify you if/when that occurs. We can also be reached via telephone: (925)646-6586, 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 (http://ucanr.edu/blogs/CCMGBlog/)
Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Client's Request: Hello. I'm looking for some help on what is eating leaves on my vegetable plants, and what may I do to help remediate. Below are some pictures.
MGCC Help Desk Response: Thank you for contacting the UC Master Gardener Program Help desk.
It is very hard to determine exactly what is causing holes in the leaves of your plants without direct observation. However, I think it may be slugs and/or snails, a common problem in spring. In order to determine if it is slugs or snails to implement an effective removal effort, you could look for slime on the leaves and slime on the ground around the plants. You could also go out at night with a flash light when they are active and check the leaves for snails and slugs.
The link following will take you to a UC Pest Management page on slugs and snails. It has some really nice videos (which are not long) on identifying whether or not slugs and snails are eating your plants. It also has a video on pest management of the slugs/snails (what to do about them). The pest note also has written information on management of snails and slugs. http://ipm.ucanr.edu/PMG/PESTNOTES/pn7427.html.
Managing snails and slugs can be done with trapping or hand picking and then snail and slug bait.
As you should always do when using pesticides, read the label on the snail bait box for use and cautions. The active ingredients that are in the snail/slug bait are in small print on the package. Metaldehyde and sodium ferric EDTA can be toxic to animals and harmful to the environment. Iron phosphate is safe for animals. The bait should be shaken around the plants.
It may also be cutworm. Management of this pest involves hand picking at night and protecting plants with cardboard collars, screens or protective cloth. The link following will take you to the UC Pest Management page on cutworms. http://ipm.ucanr.edu/PMG/GARDEN/VEGES/PESTS/cutworm.html
Finally, from my personal experience to reduce the snail/cutworm population, look for and destroy their daytime hiding places (e.g., wood debris, weeds, etc.). It's a lot easier than crawling around at night with a flashlight looking for them.
Please let us know if you have further questions.
Help Desk of the UC Master Gardener Program of Contra Costa County (DLD)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer our 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, although we will be moving this spring. We will notify you if/when that occurs. We can also be reached via telephone: (925)646-6586, 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 (http://ucanr.edu/blogs/CCMGBlog/)
Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Client's Request: Do you have recommendations on tomato cages? I bought the heavier gauge tapered cylinder ones at the “big box store”. Even though they are sturdy the bigger heavier tomato plants tipped them to the side. I then built wood ones out of 2 x 2 and 1 x 2 and they were sturdy but rotted after two summers in well-watered soil. Ideas?
Those big indeterminate varieties can get quite unwieldy! If the wire cages you have are big enough, you could try tying them to a (e.g. re-bar) stake firmly anchored in the ground to stop them falling over.
But, but if you want something more hefty, my favorite (and what we use at the Master Gardener demonstration garden) are made of concrete reinforcing mesh. This generally comes in a 5 ft. width, tall enough to roll up into a cage. You can buy a roll at most home improvement stores - sometimes you can find flat pieces, but I have not found any that are big enough to make the cage. As for how to make them, a Google search will come up with a number of sites giving clear instructions. I use heavy duty zip ties with a one square overlap to connect mine - that way I can cut the ties and store them flat at the end of the season.
One other tip - I have found that tying the cage to a re-bar stake prevents any toppling over, and these stakes last for many years.
I hope this helps, and good luck with your garden, and tomato growing!
Help Desk of the UC Master Gardener Program of Contra Costa County (SMW)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer our 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, although we will be moving this spring. We will notify you if/when that occurs. We can also be reached via telephone: (925)646-6586, 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 (http://ucanr.edu/blogs/CCMGBlog/)
Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Client's Request: My 20 year old Japanese maple (Acer spp) did not return this year. I need help identifying what the problem is and how to resolve it. Pictures below show mushroom looking things growing on the tree. Not sure if it's the cause of the dieback. Thank you in advance!
MGCC Help Desk Response: As you have already recognized, the presence of the mushrooms on the trunk of your Japanese Maple tree is not a good development. It indicates that a fungus has somehow entered the tree. Typically, such fungi enter a tree's system either through the roots or through a wound on the tree or its roots. Wounds can be caused by such things as a nick by a lawn mower or “weed eater” cutter, excavations or poor pruning practices. Fungi can also enter the tree if a “root rot” disease develops. Once the fungus has entered the tree's interior tissue, it breaks down wood fibers, releasing nutrients needed to feed the fungus. After mushrooms become visible, the attack is well underway, and the fungus has begun reproducing through spores in or on the mushrooms.
When mushrooms are present on the main trunk of the tree as appears to be the case with your tree, there is not much hope that the tree can be saved. The breakdown of the tree's internal wood fibers to feed the fungus may weaken the tree structurally and if the problems has developed from a root rot problem, the roots may be weak and less able to support the tree. For these reasons, you may want to consider removing the tree.
Without knowing more about the history of your tree and the symptoms of earlier declines to the tree's health that may have been evident in prior growing seasons, we are unable to determine the precise cause of the decline of your tree. You may be able to learn more about the possible causes of the tree's decline at this University of California website: http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/maple.html The website lists common disease problems that can affect Japanese Maple. We suggest that you look at the links for “root and crown rot” and for “wood decay” and consider whether they describe earlier signs or symptoms of a problem that you may have noticed in past growing seasons.
The abundance of pale, honey colored mushrooms shown in your photos suggest another possible fungal root disease not mentioned on the UC website referenced above. A fungus known as Armillaria mellea is the cause of Armillaria root rot. Early symptoms you might have observed if this fungi is the cause of the problem include reduced growth, yellowish leaves and dieback of twigs and branches. The development of the pale colored mushrooms around the base of the tree or the surrounding ground is a later development in the progress of the disease. If you suspect this fungus might be the cause of the tree's decline, you may want to try to confirm the diagnosis by looking for the presence of white mycelial fans between the bark and the underlying sapwood of the tree. This UC website has additional information about Armillaria root rot and includes a photo showing the white mycelial fan structures that underlie the bark: http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/DISEASES/armillariartrot.html
Keep in mind that if the source of the fungal disease was in your soil, the fungal spores may remain in the soil and could potentially affect the roots of a replacement soil. For this reason, it would be a good idea to try to determine what disease was present in your tree. You might want to consider hiring an arborist to examine the tree and confirm what caused the problem. The arborist might also be able to provide a crew to remove the tree and give you some guidance on steps to take to avoid having a replacement tree develop the same problems. Here is a link to the International Society of Arboriculture (ISA) website. It has a search feature that allows you to find a certified arborist based on where you live. https://www.treesaregood.org/findanarborist
I hope that you find this information to be helpful. Please contact us again if you have further questions.
UC Master Gardener Program of Contra Costa County (tkl)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer our 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, although we will be moving this spring. We will notify you if/when that occurs. We can also be reached via telephone: (925)646-6586, 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 (http://ucanr.edu/blogs/CCMGBlog/)
