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
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
Home gardeners should consider using fruit trees grafted to dwarfing rootstocks. Trees grafted on dwarfing rootstocks are not only shorter, but take up far less space within the home landscape. They also tend to mature and set fruit sooner than full-sized trees. Fruit trees grafted on dwarfing rootstocks are easier for homeowners to maintain and manage pests by organic means. Dwarfing rootstocks for apple, cherry, pear, prune, and plum are available to homeowners at many home and garden centers. Some nurseries sell just the rootstocks for home gardeners who are interested in budding or grafting their own dwarfing fruit trees.
Traditionally, apple trees in western Washington have been sold on semi-dwarfing rootstocks. Depending upon the vigor of the cultivar, it is not uncommon to find trees reaching a height of over 15 to 18 feet when semi-dwarf rootstocks are used. To best ensure that the total tree height will not exceed 10 feet, homeowners should select trees with fully dwarfing rootstocks such as M9, Bud 9, or M27 varieties. Full dwarfing rootstock trees are now available at independent garden centers.
The fruit on dwarf rootstock trees should be comparable in size to those found on semi-dwarf rootstocks. Full dwarfing rootstocks trees are not self-supporting. They require support either from a post or a wire trellis. Trees grown on full dwarf rootstocks typically bear fruit within 2 years, while trees on semi-dwarfing rootstocks may take 4 to 5 years.
Regardless of the rootstock chosen, overall tree size is best maintained by proper training and pruning.
For more information, see Organic Pest and Disease Management in Home Fruit Trees and Berry Bushes http://cru.cahe.wsu.edu/CEPublications/EM066E/EM066E.pdf .
Submitted by Charles A. Brun, January 20, 2015
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