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
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From your description of the dirt mounds, it sounds as though the critter in your yard may be either a mole or a gopher. The easiest way to tell the difference is by the type of mound you have.

Quoting from "Of Bugs and Blights" (in Balls and Burlaps, February 1988, pp. 4 and 14):

A gopher mound fans out from a hole near one edge of the mound. This hole remains plugged while the gopher is on the runway system. The gopher mound is relatively flat compared to the mole mound. Gopher mounds vary from 1 to 3 feet in diameter...several mounds often will be found together. They are not regularly found in a line as are mole mounds. The mole mound is somewhat conical and not much over a foot in diameter. The hole is not evident when you look at the mound. Push the soil aside and you will find it under the center of the mound. Each mound is connected with the other in a line by the moles' runway system.

According to the article quoted above, moles are more likely to be found in gardens in Western Washington than are gophers. We have the journal Balls and Burlaps in the Miller Library. The article discusses the problems and benefits of moles, as well as control methods.

I also consulted the Western Garden Problem Solver (Sunset Books, 1998) to see if I could identify your mound-maker. Ground squirrels leave their burrows open, so if your mounds show no opening, you probably don't have squirrels. Mole mounds appear volcano-like, with signs of soil excavation.

Here is a link to information on ant nests, which you might look at to see if the description more closely matches your problem.

Season All Season
Date 2007-12-13
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Kinnikinnick or Arctostaphylos uva-ursi sometimes suffers from galls caused by aphids, and is also susceptible to fungal diseases. If your plant has galls, you would see distorted, thickened, and often reddish leaves which almost don't seem leaf-like. The aphids may also secrete honeydew which can then turn blackish with mold.

Douglas Justice, University of British Columbia Botanical Garden Associate Director offers these comments on Arctostaphylos uva-ursi:

The Arctostaphylos uva-ursi cultivar 'Vancouver Jade' -- a UBC introduction and one of the most widely grown cultivars in temperate climates -- is adapted to wetter conditions than many other cultivars, as it was selected from the Pacific Northwest. Nevertheless, like all kinnikinnicks, it is not a plant for poorly drained, shaded or high traffic areas. And unfortunately, it appears to be rather more susceptible to manzanita pod gall aphid than other cultivars. Populations of that insect pest can build up during "warm winter" periods (such as we've been experiencing in Vancouver over the past several years) and disfigure plants significantly.
Source: UBC Botanical Garden Forums

Here is a link to information about leaf gall on Arctostaphylos uva-ursi from Oregon State University's Plant Disease website. Search using the term kinnikinnick.

The following, from Pacific Northwest Insect Management Handbook (WSU, OSU and U. of Idaho, 2005) provides more information about the aphids.

Kinnikinnick Arctostaphylos - Aphids

Manzanita leafgall aphid, Tamalia coweni:

Pest description and crop damage - Manzanita leafgall aphids are grayish or greenish in color and prefer new growth. They feed on the leaves of kinnikinnick and other manzanita species (Arctostaphylos spp.). Aphid feeding causes the leaves to thicken and form bright red galls. Older galls turn brown. Severe infestations may slow the growth of the plant.

Nongall-forming aphids also may be seen occasionally on kinnikinnick. They are greenish, soft-bodied insects that may feed on leaves or stems. Honeydew, a sweet, sticky material, may be associated with aphid feeding. It may attract ants or become covered with a growth of dark, sooty mold. Severe infestations may result in leaf and twig dieback.

Management-biological control: Syrphid fly larvae are important predators of leafgall aphids, and will feed on them inside the galls. Avoid use of broad-spectrum insecticides which kill these and other beneficial insects such as ladybird beetles and parasitic wasps.

Management-cultural control: Prune off and destroy galls where seen. Avoid frequent shearing and overfertilization, which encourages succulent new growth favored by aphids. Wash other aphid pests from plants with a strong stream of water or by hand-wiping. Avoid excessive watering, and use slow-release or organic sources of nitrogen. Control ants, which "farm" aphids and protect them from predators in order to harvest their honeydew.

Season All Season
Date 2008-01-03
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First you need to get an accurate diagnosis of your problems. You can try taking a sample of the problem (including insects, damage, and a healthy section of plant if possible) to a local nursery. Assuming you live in or near Seattle, you can also take the samples to a Master Gardener clinic. If they don’t know what’s wrong, ask them to send the samples to the diagnostic lab at the Center for Urban Horticulture. A third option is to send the sample to the Washington State University Extension pathology laboratory in Puyallup. It is best to go through the Master Gardeners first so you will not be charged. If you send the sample to the WSU lab yourself, there will be a fee.

To locate your nearest Master Gardener clinic, go to this link:
http://mastergardener.wsu.edu/mgoc/mgoc.html#

Master Gardener Clinics provide forms for the WSU Extension lab. They ask detailed questions about the problem and the samples. (Forms are also available at the Miller Library.) The forms and plant/insect samples can then be mailed into the WSU Extension lab for information.

Learning about insects is a bit complicated. Here is a link to some information about root weevils.

Meanwhile, most soft bodied insects (like whiteflies) can be controlled with insecticidal soap. According to Common-Sense Pest Control (Olkowski/Daar/Olkowski, 1991, pp.115-116), insecticidal soaps are nontoxic to the user unless ingested in large doses.

You can make insecticidal soap by mixing 1-2T of a mild liquid soap (like Dawn or Ivory) in 1 quart of water. Some people add cayenne or tabasco. A few drops of cooking oil will help the mixture stick to the leaves. Be sure to test a leaf to be sure the mixture does not burn the plant, since some vegetables are tender. (If you are nervous about making your own, there are several varieties on the market.) Be sure to spray the mixture on both sides of the leaves--a light spray is sufficient.

Season All Season
Date 2008-01-10
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We can't definitively diagnose without having a plant sample, but the pests most likely to cause a white, sticky substance are aphids, whiteflies, scale or mealybugs. They won't destroy plants, but can weaken them and allow other problems to surface. Information about house plant pests.

The first four pests described are the ones your jade plant (Crassula spp., and yes, they are succulents) might have. Control methods are discussed toward the end of the information at this site.

Another control method that I have used successfully on my jade plants is Neem Oil. Information on neem oil.

According to the site, it is "an organic control for many pests and is extracted from crushed kernels of the neem tree. Neem oil is biodegradable with very low toxicity. It is both a repellant and a contact killer. Insects that do not feed on treated plant foliage are unharmed; therefore, neem doesn't interfere with the natural balance of the ecosystem. It acts as an insect growth regulator that disrupts the molting process. Neem can be used to control aphids, bagworms, borers, caterpillars, leafminers, lace bugs, thrips, psyllids, mealybugs, and many other insects. It prevents mildew, rusts, leaf spots, botrytis, scab, and other fungal diseases as well."

Re: temperature and repotting
According to The New House Plant Expert (by D. Hessayon, 1991, p. 212), succulents like a difference between day and nighttime temperatures. They like to be kept cool in the winter, with 50-55 degrees F ideal, but as low as 40 is alright. Jade plants should only be repotted when essential. Repotting should occur in the spring; shallow pots rather than deep ones are preferable.

Extensive care information can be found on these websites:
hgic.clemson.edu/factsheets/HGIC1507.htm
www.succulent-plant.com/moneyplant.html

Season All Season
Date 2006-12-08
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We did some research and found some websites you can visit for possible answers to your question. You probably do need to treat your plant. If you wind up going to the nursery for any product to help in treating it, take along a sample leaf so you can get the opinion of someone who may be acquainted with the problem.

1. http://www.succulent-plant.com/pests.html
Click on the link to Pests and Diseases on the home page and then click on mealybugs (one possibility) in the left-hand menu. To kill these, you dab them with a Q-tip dipped in alcohol.

Now go back to the previous page and click on scale insects (another possible culprit) in the left-hand menu. They suggest using insecticidal sprays to kill these, but insecticidal soap may be effective.

2. This Washington State University Cooperative Extension publication contains lots of images and information about houseplant pests, including info about treatment.

Always test any spray on one leaf before spraying the entire plant.Wait a few days after the test spray. Some plants are more sensitive to various soaps or oils.

Season All Season
Date 2008-01-10
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As far as I am concerned it is perfectly normal to have all of these pests (because I also have many)! But some gardeners are more ruthless than I am. They would rip out the plants. Others would assault their garden with chemicals. I prefer the middle ground of tolerance of some damage and using low-toxic controls.

The mantra these days is RIGHT PLANT RIGHT PLACE and HEALTHY SOIL = HEALTHY PLANTS. For further information (and support) go to the Seattle Public Utilities website, which has a number of great publications on Natural Gardening. There are lots of links to browse.

You could learn more about Natural Pest, Weed, and Disease Control by looking at their pdf.

Season All Season
Date 2006-12-08
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We can’t identify pests by email or phone but there is help! If you can take a plant sample (including chewed and healthy leaves) to your local county extension agent or Master Gardener clinic, they might be able to narrow it down based on the way it has been eaten.

Meanwhile, two culprits that chew plants at night are the root weevil and the army cutworm (though May is a bit early for them). For information, go to http://pnwpest.org/pnw/insects?27IPMW08.dat or http://extension.oregonstate.edu/catalog/html/ec/ec1485/.

Season All Season
Date 2008-01-31
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There is disagreement about the extent to which certain plants repel mosquitoes. Below, please find some web sites that highlight some plants that may work.

There are eleven plants generally thought to repel mosquitoes:

Citronella, Eucalyptus, Pennyroyal, Rosemary, Rue, and Wormwood. Milder ones (in our experience) include Basil, Bay, Lavender, Sage and Thyme. With even the smallest of herb gardens, or access to a supermarket selling freshly-cut herbs, the leaves of such plants can simply be rubbed on pets and people to temporarily ward off insect attacks.

Season All Season
Date 2008-01-31
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Sorry to hear of your bare lemon tree! The loss of leaves could have been a reaction to the wind, and once the leaves are gone, the tree can become susceptible to waterlogging, pests, and diseases. It is good that you moved it inside, and that it has good light. The blister-like spots on the branches sound like a kind of scale insect, to which Meyer lemons can be prone: California red scale (Aonidiella aurantii). I do not think it would be spider mites, because they would cause stippled, yellowed leaves, and might leave telltale webs. Scale can defoliate and kill a tree. There are beneficial Aphytus wasps that can be used to control scale, but they have to released regularly to be effective and, of course, you would not do this while your tree is indoors. A good reference about scale insects and how to manage them is Pests of the Garden and Small Farm by Mary Louise Flint (University of California Division of Agriculture, 1990)

Here are two recommended books on growing citrus:
Citrus: Complete Guide to Selecting & Growing More than 100 Varieties by Lance Walheim (Ironwood Press, 1996)
Success with Citrus Fruit by Sigrid Hansen-Catania (Merehurst Ltd., London: 1998)

Season All Season
Date 2007-03-20
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Powdery mildew is a common and usually not life-threatening problem with Euonymus. Make sure the plant has good air circulation, and be sure to clean up and destroy fallen leaves which are infected. However, the symptoms of this fungal problem would be whitish coating on the leaves, rather than yellowed leaves. This makes me wonder if it is a different problem such as scale (which is actually an insect). Check and see if there are small bumps on the leaves or stems. Scale can cause yellowed leaves. If your plant has a small infestation, you can try scraping the scales off with your fingernail, prune out the most infested parts of the plant, and then apply dormant oil to the trunk and branches before growth starts next spring, or apply superior oil during the growing season. There are also other fungal and bacterial problems that could be causing the spots.

See this fact sheet from Penn State for more on Euonymus scale.

Here is a link to additional information, which comes from University of Illinois Extension. Excerpt:

Burning bush (also called Winged Euonymus) -Euonymus alatus

Cold injury - Winter injury may be caused by very low temperatures as well as drought stress. With excessively low temperatures, the moisture in the cells freezes (due to chemical compounds in plants, moisture freezes at various degrees below freezing). Drought stress already has resulted in limited moisture in the plant cells. Dry, freezing winds during the winter reduces the moisture level even farther, often resulting in dead plant tissue. Diseases can help magnify or increase susceptibility to winter kill. Nectria canker kills the sapwood tissue thus reducing or even cutting off moisture to tissue further out on the plant. Winterkill also makes plants more prone to infectious diseases and insect problems.

Dieback/canker - See bridal wreath spirea. In addition Botryosphaeria dothidea will infect and kill for similar reasons.

Winged euonymus scale - Lepidosaphes yanagicola occasionally occurs in the southern half of Illinois on burning bush. It is an armored scale. And will attack several trees as well. This scale can cause premature leaf drop, branch die back and cause the plant to become more prone to winter injury. It is found between the "wings" - the bark ridges. It does not move to the plant's leaves. The scale over winters as an adult and lays its eggs in June. Eggs may be laid for up to a month. Mating occurs before frost.

Euonymus scale - Unaspis euonymi - females are black and males are white. The scale causes the foliage to develop yellowish green spots. Heavy infestation results in early foliage drop and often stems are killed. Eggs survive by over wintering in the female body. The eggs hatch about early June in Northern Illinois. Crawlers emerge and move onto new growth or can be blown by wind to other plants.

Since I cannot diagnose the problem remotely, it makes sense to take plant samples to a Master Gardener Clinic.

Season All Season
Date 2007-08-08
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I wonder what kind of spray you have been using. Was it the Safer soap product? Aphids seldom cause the demise of a mature plant. Aphids are attracted to lots of leafy new growth, so it is best to avoid quick-release high-nitrogen fertilizer. The best way to keep aphids in check is to encourage natural predators like ladybugs, syrphid flies, lacewings, and parasitic wasps. Broad spectrum pesticides will harm the helpful insects as well, so I would avoid use of those. Mealy bugs are also a favorite of natural predators like those mentioned above. Usually, regularly spraying jets of water to knock the aphids and mealy bugs off the plant's leaves should keep the damage in check. If necessary, you can use insecticidal soap, but always test it on a small area of the plant to make sure it does not cause any damage to the leaves.

It is possible there is something else going on with your camellia. Here is a link to University of California, Davis's Integrated Pest Management website, with a list of problems affecting camellias. My own camellias do shed a certain number of healthy green leaves every year, but still manage to keep flowering. Excessive leaf drop may indicate overfertilizing, but it could also be a sign of too much or too little water. Did buds drop from the plant, or did they simply not form? Failure to form buds might be a result of cold injury (although since you had flowers in spring, this seems to not be the problem), or it could also be a sign of overfertilizing with a nitrogen-heavy product which encourages leafy growth at the expense of flowers.

You may want to bring samples of the insect-affected leaves and the insects in the soil to a Master Gardener Clinic for identification and diagnosis. You might also mention the excessive leaf drop, which can be a symptom of Sudden Oak Death (Phytophthora ramorum).

Season All Season
Date 2007-10-03
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It is possible your Bergenia and Heuchera are being nibbled by black vine weevils or strawberry root weevils. Usually you would begin to notice the damage in mid-spring. The notches won't kill your plants, but if you have a lot of black vine weevils and plants appear to be wilting, you may want to attempt to control the larvae. Spraying beneficial nematodes (Steinernema) on the surrounding soil may also help.

Below are links to information about weevils:

Black Vine Weevil from UMass Extension

Weevils from University of California's Integrated Pest Management site

Black Vine Weevils from University of California's Integrated Pest Management site

Strawberry Root Weevils from the University of Maine Cooperative Extension

Black Vine Weevil (and other root weevils) from Ohio State University Extension

Excerpt:

Adults that feed along leaf margins produce typical crescent shaped notches. Careful searches should be made to try and locate specimens since several other weevils and some caterpillars can produce this same type of notching. Moderate to light notching seems to have little effect on plant health.

Black vine weevils are oblong oval in shape, about 1/2-inch long and have a short, broad snout with elbowed antennae. The body is slate grey to blackish brown and the wing covers have numerous small pits and short hairs. This pest is difficult to distinguish from other Otiorhynchus weevils. The strawberry root weevil is usually half the size of the black vine weevil, and more brown in color. The rough strawberry root weevil is only slightly smaller than the black vine weevil but the collar just behind the head, the pronotum, is heavily pitted.

Female weevils emerge from soil pupation chambers late May to early July. These weevils must feed on plant material for 21 to 45 days before they are ready to lay eggs. After the preoviposition period has passed, the females place several eggs each day into the soil or leaf litter nearby suitable host plants. The weevils hide during the daytime at the base of plants or in mulch and leaf litter near food plants. Adults may live 90 to 100 days and usually lay 200 eggs during this time. The eggs hatch in two to three weeks and the small C-shaped, legless larvae feed on plant rootlets. The larvae grow slowly over the summer, molting five to six times. By late fall the larvae have matured and are about 5/8-inch long. The mature larvae enter a quiescent prepupal stage in an earthen cell and pupate the following spring. A single generation occurs each year.

Strategy 1: Habitat Modification - Egg and larval survival is helped when soil moisture is moderate to high in July and August. Heavy mulches also help maintain critical moisture levels. Remove excessive mulch layers and do not water plants unless necessary. Excessively damp soils in the fall also force larvae to move up the base of the plant where girdling can occur. Properly maintain rain down spouts and provide for adequate drainage of soil around plants.

Strategy 2: Biological Control Using Parasitic Nematodes - The entomopathogenic nematodes, Steinernema and Heterorhabditis spp., have been effective for controlling black vine weevil larvae, especially in potted plants. Sufficient water must be used during application to wash the infective nematodes into the soil and root zone. If the nematodes are to be used in landscape plantings, remove a much of the mulch as possible and thoroughly wet the remaining thatch and soil before and after the nematode application. Applications of the nematodes in landscapes has produced variable results.

Season All Season
Date 2007-11-09
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I'm sorry to hear of your struggle with fungus gnats. I consulted University of California, Davis Integrated Pest Management online, and here is a link to their page on this insect and methods of controlling it. Here are excerpts which may be relevant to your situation:

Purchase and use only pasteurized container mix or treat potting soil with heat or steam before using it; this will kill flies as well as the algae and microorganisms they feed on. Store pasteurized potting soil in closed containers to prevent it from becoming infested before use.

Commercially available Steinernema nematodes, Hypoaspis mites, or the biological insecticide Bacillus thuringiensis subspecies israelensis (Bti) can be applied to control fungus gnat larvae in container media.

North Carolina State University Extension also has suggestions on indoor control of this pest. Excerpt:

Potted plants and other types of interiorscaping are often the culprits. Check plants to see if the soil is excessively wet. Drain any excess water from the dish below the pot. If the weather permits, move the plants outdoors or allow the soil to dry down (not to the point where plants wilt). You can also drench the soil as mentioned previously. Then, increase the interval between regular watering and the problem should abate.

If you can possibly repot the plant(s) which had the infested soil, and use sterile potting soil, that should help. If this doesn't work, the Bacillus thuringiensis (Bt) or parasitic nematodes might be an option. I think the Bt might present problems for your chemical sensitivity, as you would need to avoid breathing it in, and prevent it from getting on your skin and clothing. However, the Steinernema feltiae nematodes should not be a problem at all. One example of a source for these is Peaceful Valley Farm Supply.

Gardens Alive also carries them.

I don't think adding sand on top of the potting soil will be effective. It might actually create a kind of crust over the top of the soil, causing a drainage problem. If you are concerned about fungus in the soil, using sterilized or pasteurized potting soil is a good idea. You can try using yellow sticky traps to catch the gnats; it can't hurt, although it won't completely solve the problem unless you are willing to repot with new soil. Most garden centers sell these traps, or you can make your own as described by New Mexico State University Extension.

You can also employ trapping techniques using yellow sticky traps. These may be purchased, or you can make them from yellow surveyors tape or yellow plastic butter tubs, etc., coated with vegetable oil, Vaseline, or other sticky material. Put these traps in a window or other well-lighted location. The adult gnats are attracted to the yellow color and get stuck on the trap. This removes them from the home environment and reduces their ability to reproduce. (They die on the trap.) After you catch a lot of gnats, just discard the whole trap or wipe the insects off and reapply the sticky material mentioned above, and you are ready to catch more.

Season All Season
Date 2007-11-14
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As you suspected, horticultural oil is petroleum-based. U.C.Davis provides information on Integrated Pest Management for bay laurel, Umbellularia californica. They note that horticultural oils are "...specially refined petroleum products, often called narrow-range, superior, or supreme oils. Some botanical (plant-derived) oils are also available."

When referring to plant-derived oils, I believe they are referring to Neem oil, as described in this information from Cornell University. Additional information from Cornell about Neem and human health is excerpted here:

Studies of azadirachtin mutagenicity and acute toxicity have shown that it likely does not pose a significant risk to human health. However, some people have exhibited skin and mucous membrane irritation from neem seed dust (Weinzierl and Henn 1991). Note that most studies have been done on azadirachtin, and may not show the effects of a whole neem product. Neem is used in some commercial human hygiene products.

Another long excerpt on horticultural oil from Colorado State University Extension suggests the following:

Essentially all commercially available horticultural oils (e.g., SunsprayR, ScalecideR, VolckR) are refined petroleum products also known as mineral oils. Impurities in the oil that are associated with plant injury, such as aromatic compounds and compounds containing sulfur, nitrogen or oxygen, are removed. Filtration, distillation and dewaxing complete the production of the finished base oil. Final formulations of horticultural oils are normally combined with an emulsifying agent that allows the oil to mix with water. This mixture usually is used at about a 2 percent dilution.

Vegetable oils also can be used as insecticides, although the type of oil can greatly affect its activity. Cottonseed oil is generally considered the most insecticidal of the vegetable oils. Soybean oil, the most commonly available vegetable oil used in cooking, has often provided fair to good control of some insects and mites.

Extracts from seeds of the neem tree, Azadirachta indica, have recently attracted attention as a source of pest management products. Several neem-derived insecticides have been developed. A number of compounds found in neem seeds, notably azadirachtin, have proven useful as insecticides. However, the oil fraction of neem seed extracts, which is mostly free of azadirachtin and related terpenoid compounds, also has demonstrated effects as a fungicide and insecticide. At least one product currently on the market, TrilogyR, consists of a largely azadirachtin-free oil fraction of neem seed extracts. It is formulated with an emulsifier and mixed with water at a concentration similar to horticultural oils (0.5 to 2.0 percent). Many over-the-counter products sold in nurseries that mention neem contain the oils of neem seed extracts.

If you know the insect on your Umbellularia californica, this chart from Peaceful Valley Farm Supply, shows which products are used to control which pests. Most of their products are safer, if not organic, but that does not mean they are safe enough to spray on leaves which will be harvested for cooking.

Season All Season
Date 2008-04-11
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From what I can determine, your Leyland cypress (x Cupressocyparis leylandii) trees are probably going to survive this attack unless they are weakened in some other way. x Cupressocyparis leylandii in California survive the Cypress tip moth, though they can be unsightly. Since California is a bit too dry for this tree, the conditions are not identical, but Natural Resources Canada does not indicate that infestations are fatal. Because you said you found evidence of tip moth (Cypress tip moth = Argyresthia cupressella), I will assume that is what the problem is, but a bit of browning, even in conifers, is not unusual right after trees are planted. Be sure that you are not overwatering, as one effect of that is the same as underwatering (i.e., tip die-back or yellowing) because too much water prevents the plant from taking water and oxygen into the roots.

The Organic Gardener’s Handbook of Natural Insect and Disease Control (ed. by Ellis and Bradley, 1996, p.183) says about pine tip moth (Rhyacionia frustrana):

“Handpicking works if only a few caterpillars are present. Pruning off and destroying infested tips in winter is a very effective control.”

I would recommend a prune-and-wait-and-see approach. April is a bit late to prune (and puts root establishment in competition with shoot regrowth), but you may be able to slow the infestation down, so go ahead and do it. Watch the trees this season and then prune again in the winter next year. Be sure to destroy (burn or bag and put in the garbage) the debris so you don't reinfect your tree.

A good gardening resource is the UBC Botanical Garden Forum. Personal testimony/experience is valuable, especially if it's regional. (You might find it useful in the future.) Several people commenting about x Cupressocyparis leylandii note that it is not a very desirable tree; one of its parents, the Cupressus nootkatensis, also called Callitropsis nootkatensis or Chamaecyparis nootkatensis, or, for that matter, plain Nootka cypress) is better. One person recommended planting small trees in the beginning, since they grow very fast. This might save you some money, should you have to replace your trees. The site does not need a password; just click on "Search" in the upper right corner.

Below is some additional information from Oregon State University about cypress tip moth. This site recommends pesticides, but from everything I read, they are not effective without multiple treatments. Since this pest is generally not fatal to the trees, it is probably not worth it to use chemicals which would be dangerous and time-consuming to apply. If you know something about the life cycle of the pest, your observations will yield more information and any manual control attempts are more likely to be effective. Natural Resources Canada also has an excellent site describing the pest's lifestyle.

Season All Season
Date 2008-05-21
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Rose Defense contains Neem, and there is some evidence that Neem is effective against sawfly larvae. As with any pesticide, you should follow the directions on the package carefully. You might want to start out with the least toxic approach first, that is, handpicking and spraying with water. Once larvae are knocked off the roses, they will not climb up again. If this doesn't seem to be helping, then you could choose a Neem-based spray or insecticidal soap, keeping in mind that the Neem product is toxic to bees, and should not be applied when bees are active. Here is a link to information from Peaceful Valley Farm Supply on Rose Defense, and here is the product label.

According to University of Minnesota Extension, sawflies are best controlled when young. You can simply pick them off by hand or dislodge them with a stick or a stream of water. If using water be sure to spray early enough in the day for the foliage to dry by sunset. This will prevent favorable conditions for fungal development. Horticultural oil, insecticidal soap and azadirachtin (sometimes called neem), are among the less toxic insecticides to treat young sawflies. Azadirachtin is slower acting. Bacillus thuringiensis (Bt) is effective on young lepidoptera caterpillars but NOT on larval sawflies.

Cornell University's Resource Guide for Organic Insect and Disease Management also discusses the uses of Neem. Here is an excerpt:
"Neem products are generally sold as emulsifiable concentrates. Neem oil soap is sold as a water-soluble liquid concentrate. While Copping (2001) reports no known incompatibilities with other crop protection agents, phytotoxicity may be a problem when combining neem oil or soap products. Read labels for specific application guidelines including determination of re-entry interval and pre-harvest interval. Range of efficacy will depend on the susceptibility of species in question and environmental conditions at time of application. However these are points to follow:
Make multiple applications. Frequent applications are more effective than single sprays because neem does not persist well on plant surfaces. Like most other botanically derived materials, it can be rapidly broken down by sunlight and washed away by rain (Thacker 2002).
Use against immature insects. Azadirachtin-based insecticides act on immature stages of insects more effectively than on eggs or adults. To reduce a build up of populations it is important to make treatments to crops targeting insects in an early stage of their life cycle. For instance, neem would likely have little effect on an infestation of striped cucumber beetle adults; however if applied to potato plants early in the season, it has been shown to greatly reduce larval activity of Colorado potato beetle.
Begin applications before pest levels are high. Antifeedant and egg-laying repellant effects show best results in low to moderate pest populations.
Neem is reported to work best under warm temperature conditions (Schmutterer 1990)."

There are quite a few different species of sawfly, and I would guess that the rose sawfly is so named because rose bushes are its primary feeding ground. If you aren't sure what is eating your roses, you may want to take samples of the affected leaves to your local county extension agent before you begin to treat the problem. You may find the images on the self-described Buggiest Rose Website helpful in comparing with the leaf damage you are seeing.

Season All Season
Date 2008-08-28
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