In the northwestern U.S., Washington State University Extension's Forest Health Notes states that the focus has shifted from using pesticides to taking preventive measures:
Excerpt:
Control methods have shifted away from direct control (e.g. spraying, felling, burning) and towards prevention of outbreaks. This course of action was chosen after thoroughly exploring direct control measures for nearly a century and arriving at a simple conclusion: They don't work. It is possible to prevent infestation with penetrating sprays on individual, high value trees such as those in campgrounds and near houses, but they need to be applied before the tree is infected and the cost of such treatments is prohibitive for any large-scale application.
Once a mountain pine beetle outbreak begins to spread, it can be stopped by thinning the stand ahead of the edge of the outbreak. This is because outbreaks expand on a tree to tree basis where the incoming beetles switch their attacks from a recently attacked-stem to the next largest tree. More importantly, infestations can be prevented by thinning stands before crown closure, an operation that not only increases the vigor of the residual stand, but also prevents the spread of an outbreak if individual trees have been attacked.
Mountain pine beetles are a natural part of western ecosystems, and for this reason will never be completely eradicated (nor should they be, as they serve to create small stand openings which are important for biodiversity of both flora and fauna). As such, the death of a few trees on your property doesn't necessarily mean an epidemic is getting started; check your trees for root disease symptoms. To maintain mountain pine beetles at their normal levels, predisposing factors for outbreak must be removed. Some of these, such as environmental stresses, are not possible to control. However, many stresses are related to stand management practices. First and foremost, two situations need to be addressed: root disease centers and overstocked stands. More details about treatment for root disease centers have been given in other WSU Cooperative Extension "Forest Health Notes;" in summary, they need to be identified and planted with resistant species. Overstocking causes trees to compete for water, light and nutrients, and thus weakens their defenses against bark beetle attack. To minimize stand stresses and maintain vigorous growing conditions, stand managers should: (adapted from Berryman: Forest Insects, 1986).

The Canadian Council of Forest Industries (CCoFI) has a task force on the mountain pine beetle. You might want to contact them for the latest update. Go to their mountain pine beetle website and follow the links for additional information, including how to contact CCoFI.

Season All Season
Date 2007-12-06
Link to this record only (permalink)

Try the Pacific Northwest Disease Management Handbook online---it has excellent photos. Search for fir.

There are several possibilities with brown spots as symptoms, especially:
*needle casts (there are 3 kinds)
*rust
*web blight
*current season needle necrosis
*shoot blight
*Grovesillea canker
*interior needle blight

Season All Season
Date 2008-01-10
Link to this record only (permalink)

In addition to powdery mildew, many dogwoods can suffer with anthracnose. In his book Dirr's Hardy Trees and Shrubs (Timber Press, 1997), Michael Dirr mentions Rutgers Hybrids (which are a cross of the kousa and florida species of Cornus). These trees were developed at Rutgers University by Elwin Orton, and are resistant to dogwood anthracnose. here is an article about these cultivars, written by Orton. This article from North Carolina State University Extension discusses powdery mildew resistance. Scroll to the second table at the end which charts cultivars and their resistance or susceptibility to powdery mildew.

Oregon State University provides information about each of the six hybrids of C. florida x C. kousa. Two of the trees on this list are resistant to powdery mildew.

Clemson University Extension offers further information about the insects and diseases affecting dogwoods.

Season All Season
Date 2008-01-17
Link to this record only (permalink)

To get some information about your maple, you can consult with a Master Gardener at a WSU Kitsap County Extension Diagnostic Clinic: http://kitsap.wsu.edu/hort/clinicloc.htm.

Regarding your question about Dogwood Anthracnose... It is a shame that so many of these beautiful trees are infected. Hopefully, the information below will help. Here is what I have found.

The U.S. Forest Service article, entitled, How to Identify and Control Dogwood Anthracnose, may be of use. Although it is somewhat technical in its language, there are excellent pictures and a section about methods of control. Here is the web address: http://www.na.fs.fed.us/spfo/pubs/howtos/ht_dogwd/ht_dog.htm.

Master Garden Products.com provides a short article about Dogwood Anthracnose that contains a “What to Do” list. Here is the web address: http://www.mastergardenproducts.com/gardenerscorner/savedogwood.htm.

Lastly, the University of Maryland College Home and Garden Information Center Integrated Pest Management Series HP #12 offers information about Dogwoods and Anthracnose as well as treatment methods. Here is the web address: http://www.hgic.umd.edu/_media/documents/hg12_001.pdf.

Oregon State University Extension’s Online Guide to Plant Disease Control provides a corroborating list of cultural controls for Anthracnose and adds an extensive list of chemical controls. Here is the web address: http://plant-disease.ippc.orst.edu/disease.cfm?RecordID=421.

Best of luck with your trees!

Season All Season
Date 2008-01-24
Link to this record only (permalink)

Thank you for your questions about Dogwoods and Anthracnose and about coppicing Cotinus coggygria. Hopefully, the information below will help. Here is what I have found.

Dogwoods and Anthracnose:

The U.S. Forest Service article, entitled, How to Identify and Control Dogwood Anthracnose, may be of use. Although it is somewhat technical in its language, there are excellent pictures and a section about methods of control.

Master Garden Products.com provides a short article about Dogwood Anthracnose that contains a What to Do list.

Lastly, the University of Maryland College Home and Garden Information Center Integrated Pest Management Series HP #12 offers information about Dogwoods and Anthracnose as well as treatment methods.

Oregon State University Extension's Online Guide to Plant Disease Control provides a corroborating list of cultural controls for Anthracnose and adds an extensive list of chemical controls.

• It stimulates rapid growth of new shoots that produce larger, bolder foliage.
• The variegation in the leaves become more intense.
• The plants produce more flowers and fruits.
• It keeps the plant in bounds.

• Smoke bush or smoke tree (Cotinus coggygria), zones 4-8
• Abelia (Abelia x grandiflora), zones 5-9
• Butterfly bush (Buddleia davidi), zones 5-9
• Trumpet vine (Campsis radicans), zones 4-9
• Blue mist shrub (Caryopteris x clondonensis), zones 6-9
• Pee gee hydrangea (Hydrangea paniculata Grandiflora), zones 3-8
• Firethorn (Pyracantha coccinea), zones 6-9
• Pussy willow (Salix spp.), zones 4-8
• Tamarix (Tamarix ramosissima), zones 2-8.

Season All Season
Date 2006-12-08
Link to this record only (permalink)

Thank you for your question about Dogwoods. There are several possible causes of leaf drop in Dogwoods. Below, please find referral information for the Master Gardeners and two websites that contain information about pests and diseases of Dogwoods and methods used to control them.

To know for sure what is causing leaf drop in your trees, you may wish to consider bringing a bagged sample of the leaves to the Master Gardeners Diagnostic Clinic here at the Center for Urban Horticulture or another of the many Clinic locations. For Clinic locations and hours in your area, please go to the King County Cooperative Extension website and scroll down to the Seattle Clinics section. Here is the web address: http://king.wsu.edu/gardening/PlantClinics.html.

The University of Maryland Cooperative Extension Integrated Pest Management Series on Dogwoods offers an extensive list of pests and diseases that prey on Dogwoods. Go to http://plantdiagnostics.umd.edu/index.cfm and search for "Dogwood." The page includes pictures as well.

You mentioned that the leaves of your trees turn brown and then drop. These symptoms are commonly found when Dogwoods have been attacked by Anthracnose. The Washington State University Cooperative Extension’s "Dogwood Anthracnose" page may be of use in helping you determine whether your trees have this disease.

Hopefully, this information will get you started. If you would like more information or have any other questions, please be sure and let us know.

I hope that your trees recover!

Season Spring
Date 2008-01-31
Link to this record only (permalink)

The USDA Forest Service has an entire web site devoted to this pest problem, and includes information on different ways of managing the Hemlock woolly adelgid.

The most effective approach is prevention, as treatment tends to be expensive and is not always effective. Information from Maryland Cooperative Extension does describe the use of dormant oil spray in late winter and summer application of horticultural oil and insecticidal soap, but care must be taken to cover the entire tree. Also, it is important to avoid the use of nitrogen-heavy fertilizers which create a lot of succulent new growth attractive to the pest.

Here at the Washington Park Arboretum, a study is under way on the use of biological controls (see links from this document).

I recommend that you consult a certified arborist for advice on how to save your (Western hemlock). You can obtain referrals from Plant Amnesty or you can select an arborist from the Pacific Northwest Chapter of the International Society of Arboriculture.

Season All Season
Date 2007-06-13
Link to this record only (permalink)

The problem you describe could be the result of drought injury, or it could be one of several rust and fungal diseases which affect fir trees. Was the tree watered well after planting? Here is a link to information on drought injury, from Oregon State University's plant disease database. Excerpt:

Drought injury usually progresses from the top of the tree downward and from the outside to the inside of the crown. Top dieback and branch death may be common. Defoliation of the mid-crown or loss of needles at the base and tip of shoots can also occur in Douglas-fir. Older needles commonly turn yellow and are shed prematurely. Roots may be alive even though the entire above-ground parts are dead. Winter injury, gopher and root weevil problems can produce similar symptoms.

Here is a link to the complete list of potential problems affecting firs.

Your description also sounds like the symptoms of Phytophthora, a fungal disease which is common in our area. Excerpt:

Phytophthora root rot is usually a problem only in areas with poor drainage or where flooding occurs. The fungus attacks the roots, which rot and die. The infection moves up into the crown, where the cambium (soft inner bark) turns reddish-brown or caramel in color instead of the normal white to greenish color. Older trees may develop cankers on the trunk, which are a dark reddish-brown when cut. The cankers may be accompanied by split bark and oozing pitch. Lower branches wilt, turn dark red, and die back. Younger trees are often killed outright, while infected mature trees may show wilting, branch dieback, and/or gradual decline.

Here is an image of Fraser fir suffering from Phytophthora.

The American Phytopathological Association provides additional information on this disease.

I recommend taking a sample of one of the cinnamon-colored branches to a Master Gardener Clinic, and also taking photos of the whole tree, so that you can have the problem diagnosed. If you are in King County, a link to clinic schedules may be found here is the list of clinics. If you are near Enumclaw, the Pierce County Master Gardeners also have clinics.

Season All Season
Date 2007-07-25
Link to this record only (permalink)

I am sending you my best guesses as to the identity of the hard, spiky nodules on your Mugo pine. I think it may be a type of scale, which is a sap-sucking insect. Here is a link.

Pine Needle Scale (This is especially common on Mugo pine, but it affects the needles, not the trunk.)

The pine needle scale is a small, white, narrow scale insect that feeds on the needles of ornamental pines. The pine needle scale is not worth treating if the population is low; however, if there are many scales on each needle, it may wise to treat with insecticide. Pine needle scale insects overwinter on the needles as eggs under the armor of the dead mother scale insect. These eggs hatch in the spring. Tiny purple crawlers emerge from under the old armor and settle down on the needles to mature and lay eggs for another generation which will mature later in the summer and ultimately produce the overwintering eggs. Pine needle scales are most damaging to ornamental pine plantings. Austrian and Mugo pines may be so heavily infested that these shrubs become chlorotic and suffer premature needle drop. Research performed by Dr. Warren Johnson at Cornell University has shown that pine needle scale insects are susceptible to oil sprays. We recommend using a 4 percent oil spray during the winter and a 2 percent oil spray now and later in the fall.

From University of California Davis. On this website I found references to ant-tended scale, but this phenomenon is associated with soft scale, which exudes honeydew and attracts the ants, so perhaps that it what the nodules on your tree are. I think the best thing would be to take samples of the nodules as well as photos of the tree and bring them to a Master Gardener Clinic for in-person identification.

Here is one example of a honeydew-producing scale that affects Pine. Here is another link. Excerpt:

The Pine tortoise scale, gets its name from the characteristic appearance of the mature females. They look like tiny tortoises up to 1/4 inch in diameter and are most often found on 1- and 2-year-old shoots of "hard" pines. Scots pine and jack pine are the two species most severely attacked by pine tortoise scales, but red and Austrian pines are also affected.

Pine tortoise scale insects overwinter on host twigs as immature females. They are reddish brown and slightly wrinkled, but shiny, when they first begin to develop on the twigs. The females resume growth in the spring, reaching maturity in June. The, eggs are laid beneath the female's body (up to 500 per female!) and the amber-colored young scale crawlers begin to emerge in late June or early July. Males will die after mating, while females will develop until the cold temperatures of autumn force them into dormancy. These insects also produce honeydew, a substrate for the growth of a sooty mold fungus that blackens affected plants.

Sorry not to be able to make a conclusive identification remotely, but perhaps this information will include images that resemble what you are seeing on your tree.

Season All Season
Date 2007-07-27
Link to this record only (permalink)

Birches are commonly afflicted with aphids, and the aphids suck sap and secrete honeydew, which can be a nuisance, and is usually why homeowners contact us. Unfortunately, if your birches are overhanging a sidewalk, it is probably getting sticky from the honeydew. Otherwise, you could probably ignore the problem (except in the most severe infestations).

You can try spraying the aphids off the leaves with a strong jet of water. You can also encourage natural predators. Avoid over-fertilizing, or exposing the trees to lawn fertilizer, for example, as this will lead to succulent new growth which attracts aphids. Make sure the trees are not under any stress, as aphids are more likely to feed on a weakened tree. You may be able to avoid using the insecticidal soap as a control. If you do use it, you are correct that you need to reach all leaf surfaces, which is labor-intensive. Some of these soaps can cause damage, so it is always a good idea to test any such spray on a small area before coating the whole plant. An article by Colorado State University Extension provides information on insecticidal soaps. Aphids go through many generations in a year, and their eggs can overwinter.

Washington Toxics Coalition has created a document on managing aphids in the landscape.

Here are additional links on aphid control: Aphids from University of California at Davis
Managing Aphid Problems without Pesticides from the Northwest Coalition for Alternatives to Pesticides

Season All Season
Date 2007-08-01
Link to this record only (permalink)

I may be offering you information you have already seen. University of British Columbia Botanical Garden's forum has this to say. Excerpt:

In the west, cypress tip moth sometimes infests cypress (Cupressus and Cupressocyparis) and false cypress (Chamaecyparis); those are also sometimes called cedars. In the east, cedar often refers to Juniperus (red cedar), Thuja or Chamaecyparis (white cedar); all are subject to bagworm infestations and various tip-miners. In the west, timely shearing is the most effective way to control cypress tip moth, and this may also be a tactic in other parts of North America.

In many cases, infestations occur because there are few natural enemies about to reduce pest levels. Sometimes, pests are attracted to plants that are already weakened by stress. Healthy plants and diverse plantings, together with a reduction in pesticide use, will over time, increase beneficial organisms which will in turn reduce pest levels. Spraying to reduce pests generally affects beneficials to a greater degree than the actual target pest. This is because pest species often have a greater capacity to rebound -- they often reproduce faster, have a greater tolerance for pesticide residues and have a greater capacity to become resistant to pesticides.

Oregon State University's IPM site only mentions toxic controls.

From an online forum, 'Horticulture Guy:'

Q. I have a row of 16 - three year old "Emerald Green" arborvitaes. I suspect they have arborvitae leafminer (cypress tip moth). I have noticed the moths before, but now there are more and I just recently noticed brownish-yellow tips on a couple of the trees. All of them have lots of needles falling from the interior. My problem is that I have received conflicting reports about the proper time to spray for them, and is there anything I can do in the meantime to lesson the damage? Thank you! Linda Brieger - Tacoma, WA

A. The way to gain control over any pest population is to know its life cycle. Spraying is geared toward eliminating the adult form of the insect, which is a moth as the second of the two common names indicates. The most likely reason you may see conflicting reports on when to spray the moths is because of varying times the moth may emerge in different regions where they are present. They are generally active in our area from April to June with a peak of activity in May. The moths lay their eggs during this period and the eggs hatch and then burrow into the needles of the host plant. According to the WSU extension the adult moths are silver-tan and approximately 1/4" in length. External sprays won't have an effect on the larvae once they burrow so you need to spray weekly during this period to catch the larvae as they hatch. Systemic insecticides are able to kill the larvae once they are in the host. You can limit systemic insecticide spraying to one application near the beginning of the activity since they generally remain effective for some time (see labels for instructions). As far as "in the meantime" a sprayless solution is to prune out and destroy infected parts of the host now so that there are less moths in the spring. You can also keep an eye out in the spring for the white cocoons that form after the larvae exit the host to become adult moths. You can remove these as well.

University of California Integrated Pest Management suggests that proper cultural care and removal of susceptible plants is the answer. Excerpt:

Provide proper cultural care to keep plants vigorous. Prune out and dispose of foliage infested with immature leafminers to restore the plant's aesthetic appearance and provide some control. Consider replacing plants especially susceptible to the cypress tip miner. High populations and damage can be reduced on established plantings by applying a broad-spectrum, persistent insecticide such as acephate on susceptible varieties when adult moths are active. Beginning in early spring, examine foliage tips for the cocoons. When these appear, vigorously shake foliage and watch to see if silvery tan, tiny moths fly up then settle back on the foliage. One application to foliage can be made when a large number of tip moths appear, between March and May in California. This reduces browning next season.

You could try using the Neem oil (instead of the more toxic alternatives) although I did not find any information specifically suggesting this as a control for cypress tip moth. The WSU book, Pacific Northwest Landscape IPM Manual (2002) suggests natural parasites which attack this species of insect, but they do not specify the identity of these predators. They state that there are no "biorational pesticide management options" for this pest.You can get an idea of potential parasitoid natural enemies from entomology sites such as this one from the University of Idaho.

Season All Season
Date 2007-08-10
Link to this record only (permalink)

I consulted The Organic Gardener's Handbook of Natural Insect and Disease Control edited by Barbara Ellis (Rodale Press, 1996), and this resource recommends doing what you already did, by removing and destroying affected parts of the tree. At the beginning of the growing season (early spring) you can spray sulfur to control this fungal disease on blossoms. If you were growing fruit, you would spray again later in the season to protect the fruit, but since this is an ornamental tree, it isn't necessary. Copper sprays are also used to control the disease. Washington State University Extension recommends preventive measures, such as avoiding wounding trees (damaging bark with string trimmers/weed-whackers/lawnmowers, or making bad pruning cuts). Avoid wetting the blossoms and leaves, and keep the tree pruned for good air circulation in the canopy. Avoid excessive nitrogen fertilizer. While the tree is in bloom, check it frequently for symptoms, and destroy any diseased parts as soon as you notice them.

I found sources for less toxic (but still not hazard-free) versions of these fungicides from Peaceful Valley Farm & Garden Supply, but they may be available at your local garden center as well. Some of these require a pesticide handler's license.

BSP Lime Sulfur Fungicide

Basic Copper Sulfate

Season All Season
Date 2007-10-11
Link to this record only (permalink)

There are a number of reasons that plants may fail to flower, and it would be difficult to pinpoint precisely why the Magnolia made such a weak show this past summer. Sometimes, cold temperatures kill off flower buds (and there were some cold snaps last winter). The tree is not immature, and it sounds as if it is not pruned improperly, so those potential causes can be excluded. You also indicate that it is not fertilized, so it is probably not receiving excessive nitrogen which can lead to lots of leafy growth at the expense of flowers. I wonder if anything else in its environment has changed: has the amount of light changed (any new construction obstructing sun?), or has anything happened to the soil where it is planted? You might wait and see if flowering returns to normal this year. As for the yellowed leaves, that might be a result of winter injury (desiccation) or drought stress. However, yellow leaves can also be a symptom of sunburn or lack of light, or nutrient deficiency. See the link here to University of California, Davis's page on Magnolia problems. Excerpt:

Mineral deficiencies

Certain nutrients, in relatively small amounts, are required for healthy plant growth. Deficiencies can cause tip chlorosis or necrosis or cause foliage to discolor, fade, distort, or become spotted, sometimes in a characteristic pattern that can be recognized to identify the cause. Fewer leaves, flowers, and fruit may be produced, and these can develop later than normal and remain undersized. More severely deficient plants become stunted and exhibit dieback. Commercial laboratories can conduct foliage tests or soil analysis to verify deficiencies.

Identification

Solutions

Nitrogen and iron are the only nutrients in which woody landscape plants are commonly deficient. Poor root growth caused by water-logged soil, root diseases, and nematodes can also cause iron deficiency symptoms. Fertilize only as needed and only if other problems have been eliminated as the cause of poor growth. Avoid overfertilization, especially with high-nitrogen fertilizers. Slow-release formulations of nitrogen or organic fertilizers reduce some risk of overfertilization. Correcting deficiencies of minerals is tricky. Apply only the mineral found to be deficient. In some cases, soil characteristics may exacerbate deficiencies. Alkaline soil (high pH) often makes iron or manganese less available; reducing alkalinity with sulfur or organic amendments (peat moss) may be all that is needed. Some minerals such as iron, manganese, and zinc are absorbed more rapidly as a foliar spray than a soil application.

If the environmental causes don't ring true with your tree's situation, you may want to do a soil test to see if there are nutrients which need to be supplemented.

Season All Season
Date 2008-01-09
Link to this record only (permalink)