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Gardening in Washington State

Archive for May 2014

Protect your apples from codling moth this season!

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.

FIg 1
Figure 1) Codling moth is about 3/8 inch-long; one female moth will lay dozens of eggs. When eggs hatch, larvae bore directly to the fruit’s core. Photo Credits: Michael Bush, WSU Extension

Fig 2
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.

Management 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.

Fig 3
Figure 3) Backyard apple tree with commercially available apple bags.

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


Voles in the garden

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


Growing Squash in Home Gardens

Consider this: There are few vegetables easier to grow in the home garden and more versatile in form/use/consumption than squash. The term “squash” refers to several plant species native to Central and South America. Many squash types or cultivars can be grouped as summer squash or winter squash, depending on the season the vegetable is harvested.

Summer squashWinter squash

Summer Squashes: Zucchini & Crookneck       Winter Squashes: Buttercup & Turban

Photo Credits: Michael Bush, WSU Extension

May is time to plant in most regions of WA State: Squash is a frost-tender vegetable. Seeds may not germinate in cold soil and seedlings can be killed off by spring frosts. Squash is planted in hills (mounds of soil) about 4 to 5 feet apart. Sow 4 to 5 seeds per hill at a depth of one inch in mid- to late May, depending on the date of the last killing frost. Alternatively, start plants in the home or greenhouse 10 days to 2 weeks prior to transplanting seedlings into the garden. Spacing is important when planting these seedlings; place 2 seedlings per hill spaced 4 to 5 feet apart.

For more information on growing squash in home gardens, go to


Submitted by: Michael Bush, May 1, 2014

Gardening in Washington State, Puyallup Research and Extension Center

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