LaGasa, Eric

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6. Biology / Phenologya. Biology1. Exotic Fruit Tree Pests in Whatcom County, WashingtonEric LaGasaPlant Services Div., Wash. St. Dept. of AgricultureP.O. Box 42560, Olympia, Washington 98504-2560(360) 902-2063 a348sproolwa@attmail.comThe Washington State Department of Agriculture (WSDA) has conducted detection surveys and otherfield projects for exotic pests since the mid-1980's, with funding provided by the USDA/ APHISCooperative Agricultural Pest Survey (CAPS) program. Recent discovery of several exotic fruit treepests in northwestern Washington prompted a 1994-1995 CAPS survey of apple trees to identify allleaf-feeding apple pests currently in Whatcom County. Additional exotic apple pest species, new toeither the region or U.S. were discovered. This paper presents some brief descriptions of speciesdetected in that project, and other exotic fruit tree pest species discovered in northwest Washingtonsince 1985.Table 1. - Exotic Fruit Tree Pests New to Northwestern Washington State - 1985 to 1995green pug moth - Geometridae: Chloroclystis rectangulata (L.)An early, persistent European pest of apple, pear, cherry and other fruit trees. Larvae attack buds,blossoms, and leaves from March to June. Damage to blossoms causes considerable deformation offruit. Larvae are common in apple blossoms in Whatcom County, where it was first reared from appletrees in 1994. This pest, new to North America, was also recently detected in the northeastern U.S.Croesia holmiana - Tortricidae: Croesia holmiana (L.)A common pest of many fruit trees and ornamental plants in Europe and Asia, where it is considereda minor problem. Spring larval feeding affects only leaves. First reported in B.C. in 1977, this pesthas been collected in large numbers in survey traps (for other pest species) throughout the PugetSound area since the mid-1980's. Reared from apple trees in Whatcom County in 1994, larvae arecommon on apple trees in that county. This pest is not known to occur anywhere else in NorthAmerica.apple leaf midge - Cecidomyiidae: Dasineura mali (Rieffer)This apple leaf feeding gall-fly was first reported from Whatcom County in 1994 by Dr. ElizabethBeers, who was contacted by a field consultant seeking a treatment for this unrecognized pest. Larvalfeeding damage from three or more generations per year is limited to new leaves, but heavypopulations can reduce growth and stunt young trees. Originally from Europe, apple leaf gall midge isalso found in the northeastern U.S., eastern Canada, and New Zealand. Although now common innorthern Whatcom County, the 1994 discovery may be the first documentation of this pest in westernNorth America.cherry bark tortrix - Tortricidae: Enarmonia formosana (Scopoli)An unusual bark-feeding European tortricid pest of many Prunus spp., apples, and someornamentals. Larvae attack the bark of older trees. Branches and whole trees may be killed.Reported in B.C. in 1990, it was found in Whatcom Co. in 1991. Much of the Puget Sound area is nowinfested. Most older cherry trees in Whatcom County are very heavily infested, particularly graftedflowering cherry varieties. This difficult-to-control pest is also new to North America.green budworm - Tortricidae: Hedya nubiferana (Haworth)This European leafroller is also found in the Eastern U.S. and Canada. Considered a minor pest inEurope, the literature notes the pest as sometimes abundant in unsprayed orchards. Overwinteringlarvae feed on opening leaf and blossom buds in spring, and may also bore into and kill new branchtips. First described from B.C. in 1914, a few specimens reared from apple leaves in Whatcom Countyin 1994 are the first known detections in the Western U.S.55European common emerald - Geometridae: Hemithea aestivaria (Hiibner)Overwintering larvae feed in the fall and spring on many plants, including most fruit trees in Europewhere it causes minor damage. First discovered in B.C. in 1978, it was reared from apple trees inBellingham in 1994. This pest is not known to occur anywhere else to North America.winter moth - Geometridae: Operophtera brumata (L.)A common and destructive pest of many ornamental plants, fruit trees, and forest trees in Europe.Larvae feed on buds, leaves, and blossoms from very early spring until June. Damage to blossomsand developing fruit produce a high percentage of distorted fruit. Persistent and extensive damagehas been reported from introduced populations in eastern Canada, Oregon, and B.C.. Apple, cherry,maple, and many ornamental trees have been heavily defoliated in areas ofWhatcom County sincediscovery of the pest there in the mid-1980's.Pandemis heparana - Tortricidae: Pandemis heparana (Denis & SchifF.)Larvae feed on many trees and shrubs, including apple, pear, plum, and some berries. Typicalleafroller damage in spring mostly affects leaves, but flower and fruit feeding can cause loss orblemishes. Common in Europe, where it is considered a minor pest, it was found in B.C. in 1978, andreared from apple trees in Whatcom County in 1994. Recently discovered in museum collections inNortheastern States, it is probably also established there.barred fruit tree tortrix - Tortricidae: Pandemis cerasana (Hiibner)Another European species of Pandemis, similar in appearance and biology to P. heparana, butconsidered more of an economic pest. Blossom and fruitlet damage from large populations produceblemished fruit of apple, pear, cherry, plum, and other fruit crops in Europe. Also found in B.C. in1978, and reared from apple trees in Whatcom County in 1994. This species is not known to occuranywhere else in North America.lesser bud-moth - Gelechiidae: Recurvaria nanella (Hiibner)Larvae of this pest feed on leaves and blossoms of apple, plum, and many other fruit trees in earlyspring. Originally from Europe, where it is a destructive pest, this pest was also introduced intoNortheastern U.S. in the late 1700's. It is now common in apple buds before bloom in much of theEast. It was first recorded as a pest of apples in B.C. in the 1950's. Specimens reared from appleleaves in Bellingham in 1994 may be the first from the Western U.S.Swammerdamia pelicaria - Yponomeutidae: Swammerdamia pelicaria (Retz., 1783)The distinctive larvae of this pest feed on the upper surface of apple and hawthorn leaves in early andlate summer. It is native to Europe and Asia, where it is not considered an important pest. This pestwas probably first recorded in Bellingham in 1942, and later in B.C. in 1979, although changes inspecies name confuse the first records. It is included in this list of recent discoveries because, otherthan the single 1942 collection record, no other information on its presence or populations inWashington exist. It was reared from apples leaves in Whatcom County in 1994 where larvae arenow common. The WA/B.C. population of this pest is the only known infestation in North America.apple ermine moth - Yponomeutidae: Yponomeuta malinellus (Zeller)Web spinning larvae feed on apple leaves from April to June. Fruit may also be deformed where itcomes in contact with larval webs. Backyard apple trees in some areas ofWhatcom County werecompletely defoliated by this pest in the late 1980's. First discovered in B.C., Canada in 1981, thisEuropean pest is not found anywhere else in North America. Since discovery in Whatcom County in1985, it has spread throughout all ofWashington and into Oregon. Introduced biological controlagents are now established in several western Washington counties.cherry ermine moth - Yponomeutidae: Yponomeutapadella (L.)European cousin of the apple ermine moth, the larvae feed on more hosts, including most Prunus spp.,hawthorn, mountain ash, and serviceberry. First discovered in B.C. in 1992, and confirmed inWhatcom County in 1994, this species is new to North America. A 1995 survey found small numbersof the pest as far south as Lewis Co., but not in E. WA.56

Exotic fruit tree pests in Whatcom County, Washington

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Exotic fruit tree pests in Whatcom County, Washington

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