Horticultural Pest and Disease Board

Pest & Disease Information

Cherry fruit fly

Cherry fruit fly attacks all varieties of cultivated and wild cherries. Maggots, which develop inside the cherries, make the fruit unmarketable. Poor control can have serious consequences since major markets for Northwest cherries, such as California and many foreign countries do not tolerate any infestation of packed cherries. 

Codling moth

The Codling moth originated in Asia Minor, but has been a principal pest of apple and pear in North America for more than 200 years.  They spend the winter as a mature larva in a cocoon, in litter at the base of the tree, in wood piles, on picking bins in the orchard or on farm buildings near packing sheds where culled apples might have been dumped. Damage is caused by feeding of the larvae in fruit. Deep entries occur when larvae bore to the center of the fruit and feed on seeds. Stings are shallow entries where the larvae died or gave up and tried another place. Read the full article at: http://treefruit.wsu.edu/crop-protection/opm/codling-moth/

San Jose Scale

The San Jose scale was once a devastating pest of fruit trees. In 1922, more than 1,000 acres of mature apple trees were killed in southern Illinois by this insect. The scale was first introduced in the United States in 1870 in the San Jose Valley of California on nursery stock shipped from the Orient. With the introduction of the long-lasting chlorinated hydrocarbon insecticides, namely DDT, during World War II, San Jose scale disappeared from the scene and was no longer a threat to the commercial fruit producer.

Apple maggot

Apple maggot is a native North American pest whose original host was hawthorn. The first confirmed apple maggot infestations in the Northwest were in Oregon in 1979. Since then, trapping programs have located maggots in western Washington and western Oregon. It is likely the maggot was introduced to the western United States by people transporting infested fruit from the eastern states, being very adaptable, can infest many different plants including apple, hawthorn, plum, apricot, pear, sweet cherry, sour cherry, wild rose, Cotoneaster sp. and Pyracantha sp. Read the full article at: http://treefruit.wsu.edu/crop-protection/opm/am-control_waapple-growers/

Little cherry virus (LChV)

Little cherry virus (LChV) causes trees to produce smaller than normal fruit. The fruit produced doesn’t ripen normally or taste as good. This virus spread rapidly across the fruit growing area of British Columbia almost destroying British Columbia’s cherry industry. LChV-1 and LChV-2 have been described from Oregon and Washington including a mixed infection of both viruses. 'Deacon', 'Lambert', and 'Sam' are most susceptible to little cherry disease but it also occurs in 'Bing' and 'Sweetheart.' Read the full article at: http://treefruit.wsu.edu/crop-protection/disease-management/little-cherry-disease/

Dogwood Borer (Clearwing)

The dogwood borer (DWB), a native clearwing moth, can be found from southeastern Canada to Florida, and as far west as the Mississippi. The insect has a wide host range including dogwood, pecan, oak, plum, and apple. The DWB has one generation per year throughout its geographic distribution. On apple, DWB larvae feed primarily in burrknot tissue on clonal rootstocks. Burrknots are aggregations of root initials which can develop on the above ground portion of the rootstock. All commercial dwarfing and semi-dwarfing rootstocks have a tendency to develop burrknots.

Pear Psylla

The pear psylla, (pronounced sil-la), is the primary pear pest in North America. It was accidentally introduced into Connecticut in about 1832 and remained an Eastern pest until it was found in the Spokane Valley of Washington State in 1939. The psylla has since spread to all the pear growing areas of the United States and Canada.


Fire Blight

Fire blight is an important disease effecting pear and apple. Infections commonly occur during bloom or on late blooms during the three weeks following petal fall. Increased acreage of highly susceptible apple varieties on highly susceptible rootstocks has increased the danger that infected blocks will suffer significant damage. In Washington, there have been minor outbreaks annually since 1991 and serious damage in about 5-10 percent of orchards in 1993, 1997, 1998, 2005, 2009, 2012, 2015, 2016, 2017, and 2018. Read the full article at: http://treefruit.wsu.edu/crop-protection/disease-management/fire-blight/


Check out more on our Pest Identification Presentation

Posted: 12/24/2014 07:46 AM
Last Updated: 03/23/2021 04:48 PM

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