Have you ever wondered what causes the spots on your salal bushes?
Landscape Plant Problems: A Pictorial Diagnostic Manual will help you identify all kinds of plant problems so that you can take steps to eliminate them. Vivid photos from real-life Northwest landscapes illustrate signs and symptoms of disease, insects and mites, and cultural or environmental problems as they occur on 78 popular ornamental and fruit-bearing plants. A special section shows problems common to a larger number of plants and signs of herbicide damage. The introduction provides five simple steps to identify and diagnose the cause of plant problems. Learn to use the clues WSU experts teach Master Gardeners.
Submitted by: Carrie R. Foss and Jenny Glass, June 22, 2015
For nearly every plant in the home landscape, there is an aphid species that feeds on it. Fruit trees are no exception. Apples host a green apple aphid, cherries host a black cherry aphid (Myzus cerasi), and peaches and nectarines host a green peach aphid (M. persicae). While aphids rarely damage the fruit itself, they can compromise the health of a fruit tree, reduce the size of the fruit, and deposit a sticky substance called honeydew on the surface of fruit and leaves.
There are many beneficial insects that graze on aphids, and in most years, these natural enemies do a fair job of keeping aphid populations in check. Beneficial insects include lady beetles, lacewings, syrphid flies, and parasitic wasps that sting and lay eggs in aphids. Learn to recognize these beneficial insects and conserve them. Many types of beneficial insects can be drawn to the home landscape by planting certain flowers in the yard, such as asters and legumes, as ground cover beneath the fruit tree. Perhaps one of the best ways to conserve these biological agents is to minimize pesticide use. Organic pesticides products should only be used when necessary to protect the fruit and maintain the health of your tree.
For more information on organic management of tree fruit pests see the WSU Extension manual EM066E- Organic Pest and Disease Management in Home Fruit Trees and Berry Bushes by Drs. Charles Brun and Michael Bush on-line.
For more information on beneficial arthropods in the home landscape, see the WSU Extension manual EM067E- Beneficial Insects, Spiders, and Other Mini-Creatures in Your Garden: Who They Are and How to Get Them to Stay by Dr. David James on-line.
Submitted by: Michael R. Bush, June 8, 2015
Plant diseases caused by fungal pathogens are very common in home gardens in the Pacific Northwest, particularly west of the Cascade Mountains. Spring rains combine with warm temperatures and tender new plant growth to create ideal conditions for fungi to thrive and spread. Common fungal diseases seen in home gardens include powdery mildew, downy mildews, rusts, and late blight. Fortunately, there are many products available to home gardeners for managing diseases caused by fungal pathogens on plants. This fact sheet describes organic fungicides and provides information on:
• which organic fungicides are legal and available to home gardeners,
• how effective these organic fungicides are, and
• whether the products have unintended effects on people or the surrounding environment
More information is available on this free, downloadable fact sheet: http://cru.cahe.wsu.edu/CEPublications/FS128E/FS128E.pdf
Submitted by: Linda Chalker-Scott, May 15, 2015
As a newcomer to our home landscapes in the Pacific Northwest (PNW), the European paper wasp, Polistes dominula, has a reputation as both a beneficial predator and a pest. The European paper wasp is a relatively tame wasp that forages within landscape plants in search of leaf-feeding caterpillars and other insect prey. However, it is also a nuisance pest that will sting people who accidentally disturb or threaten it or its nest.
In early spring, homeowners may remove wasp nests by knocking them down with a long broom, pole, or strong stream of water from a hose. This is the best time to remove a nest because only a single female will be guarding it. It may take repeated removal of each nest to discourage the wasps from replacing it. It is important to wear gloves and protective clothing to reduce any risk of getting stung, and although the sting is mild, it will get your attention.
For more information, go to The European Paper Wasp FS152E located at http://cru.cahe.wsu.edu/CEPublications/FS152E/FS152E.pdf.
Submitted by: Mike Bush and Todd Murray, March 31, 2015
Acetic acid is one of the few chemicals with two common names. Both depend upon its concentration. “Vinegar” means concentrations up to 8%. “Acetic acid” means concentrations higher than 8%. When the concentration is low enough to be called vinegar, it is a food product. When the concentration is high enough to be called acetic acid, and it is used to kill weeds, it is a pesticide. The point to remember with acetic acid is that high concentrations are more effective on woody perennial weeds, while low concentrations will work effectively only on very young weed seedlings.
For more information on using acetic acid/vinegar as a pesticide, see WSU FS161E.
Submitted by: Catherine Daniels, March 9, 2015
Before planting a backyard cherry tree, homeowners should consider the challenge of pest management, especially management of the western cherry fruit fly (WCFF).
Fruit infested with the cherry fruit fly larvae, known as maggots, may have a dimpled appearance, but the maggots can still be difficult to detect when examining the surface of the fruit. However, as the maggots mature, they break the surface of the cherry and open a hole in order to breathe and exit the fruit.
There are relatively few proven strategies that homeowners can use to manage this pest. The primary non-chemical strategy to manage WCFF is to pick off every cherry from the tree at harvest. WCFF management will be considerably easier for homeowners who plant fruit trees grafted to dwarfing rootstocks. For a list of pesticides (including organic products), homeowners can access the WSU Hortsense website at http://pep.wsu.edu/hortsense/ .
For more information on organic management of tree fruit pests see the WSU Extension manual FS125E- The Western Cherry Fruit Fly and Your Backyard Cherry Tree by Michael Bush and Marianne Ophardt on-line at http://cru.cahe.wsu.edu/CEPublications/FS125E/FS125E.pdf
Submitted by: Mike Bush, February 9, 2015
There are a number of animals that can cause damage to lawns, gardens and crops in Washington through their tunneling habits. The most common pests are moles, voles, gophers and rats. Ground squirrels in eastern Washington and chipmunks statewide also burrow but are active during the day and so are usually easy to visually identify…but what about those diggers you never see? The new WSU Extension Fact Sheet, “What is Tunneling in My Yard” will help you identify the guilty parties so you can plan your management strategy.
For more information please see What is Tunneling in My Yard? FS143E
Posted by: Dave Pehling, September 11, 2014
Drosophila suzukii, commonly known as Spotted Wing Drosophila or SWD, is of concern to home gardeners and commercial producers. It was first detected in the continental US in California in 2008 and quickly spread up the coast into Canada and across the country. There are over 2,000 native drosophila flies in the US but SWD is unique in that it lays eggs inside ripening fruit as well as rotting fruit. The maggots hatch from these eggs and feed inside fruit, rendering it inedible.
It is considered a serious threat to fruit and berry crops including cherry, raspberry, blackberry, blueberry, strawberry and some peach varieties. There may be several generations of SWD produced during the growing season, which makes this pest particularly difficult to manage, especially on crops ripening after July. Preventing the spread of SWD in home gardens can ensure the production of homegrown fruits and berries and reduce the threat it poses to commercial producers of fruits and berries.
For information on detecting and managing this pest, see:
Spotted Wing Drosophila (SWD) Monitoring, Identifying, and Fruit Sampling. FS049E and WSU Hortsense,
Submitted by: Dave Pehling, June 26, 2014
If you grow apples, the codling moth will come! The larva of this common pest, also known as “the worm in the apple,” directly impacts the eating quality of apples across the state of Washington. When left unmanaged in backyard trees, the codling moth can damage as much as 80 to 95 percent of the fruit—making it “wormy” and unfit to eat.
Figure 2) Apple fruit with signs of codling moth infestation; look for the conspicuous piles of brown granular excrement plugging the entrance hole on the surface of the apple. Photo Credits: Michael Bush, WSU Extension
Washington homeowners must protect their apple or pear fruit from two, or sometimes three (in the warmer regions of the state) generations of codling moth each year. The adult moths fly during warm evenings, with peak activity in May, July, and late August. The best means of protecting backyard fruit trees from codling moth infestation is an integrated pest management (IPM) program utilizing several control strategies.
1) Plant your fruit trees on dwarfing or semi-dwarfing rootstocks.
2) Scout your fruit (weekly) from late May to apple harvest time for signs of codling moth larvae infestation. Pick off infested fruit and crush to kill larvae protected inside the fruit.
3) When the fruit is less than 1 inch in diameter (early to mid-May), individually bag each fruit left on the tree. Standard paper bags or commercially available apple bags can be used.
4) If pesticides are used, they must be applied during adult moth activity so that the pesticide covers the fruit surface before the eggs hatch. Pesticide sprays should start 17 to 21 days after full bloom (about 10 days after most of the flower petals drop from the tree) to target the newly hatched larvae before they bore into the fruit. For a list of effective pesticides used to manage codling moth, homeowners can contact their local WSU Extension office or visit the WSU Hortsense website.
For more information, see Codling Moth and Your Backyard Fruit Tree.
Submitted by: Michael Bush & Marianne Ophardt, May 23, 2014
Did your tulips fail to emerge this spring? Did most of your planted peas disappear? Are there tunnels in your garden? If so, voles may be to blame.
Although not a mouse, voles are sometimes called “meadow mice” based on their close resemblance. The two species most often responsible for vole-related backyard and garden damage in Washington are the Townsend’s vole (west of the Cascade Mountains) and the Montane vole (east of the Cascade Mountains).
These voles prefer succulent grasses, forbs, roots and bulbs but will also readily feed on the bark and roots of woody plants during winter when other food sources are scarce.
For information on how to manage voles in your garden and landscape, see the WSU fact sheet, Vole Management in Home Backyards and Gardens.
Submitted by: Dave Pehling, May 8, 2014