insects and ergot in kentucky bluegrass seed production fields in the pacific northwest

Special Report 1044September 2002

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Insects and Ergot in Kentucky Bluegrass SeedProduction Fields in the Pacific Northwest

OREGON STATE UNIVERSITY

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,UNtVERSiTY EXTENSION SERVICE

This publication is available on the Web at http://eesc.oregonstate.edu

For a print copy, write:

Marvin ButlerOregon State University Extension ServiceJefferson County office34 SE D StreetMadras, OR 97741

Insects and Ergot in Kentucky Bluegrass SeedProduction Fields in the Pacific NorthwestM.D. Butler, S.C. Alderman, P.C. Hammond, R.E. Berry, W.J. Johnston, and C.R. McNeal

Kentucky bluegrass (Poapratensis L.) seed is producedon nearly 100,000 acres in thePacific Northwest. Drylandproduction occurs in SpokaneCounty, Washington, andKootenai County, Idaho. Themajor irrigated productionareas include the GrandeRonde Valley near La Grandeand Elgin, Oregon; theRathdrum Prairie betweenSpokane, Washington, andCoeur d'Alene, Idaho; and theMadras and Culver areas incentral Oregon. All threeirrigated areas are semiarid.

Kentucky bluegrass fieldsgenerally are planted in Aprilor May, although plantingoccurs in August in centralOregon. The grass is grown asa perennial for 3 to 5 years.

Harvest of Kentuckybluegrass seed begins about thefirst of July in all areas.Postharvest residue manage-ment in Oregon generallyincludes thermal treatmentsuch as open field burning ortreatment with large propaneburners. Burning is not allowedin Washington, and residuethere typically is baled. In

Idaho, residue managementmay include baling, burning, orboth.

This paper summarizespreviously published work(Butler et al., 2001), in whichKentucky bluegrass fields weresurveyed for insects and thefungal disease ergot. Theassociation of insects and ergotalso was investigated. Theassociation of ergot and insectsin Kentucky bluegrass seedproduction previously had notbeen investigated.

Insect pests ofKentucky bluegrass

Several insect pests arefound on Kentucky bluegrassin the Pacific Northwest.• The winter grain mite

(Penthaleus major) cancause severe damage inKentucky bluegrass fields byfeeding on plants throughthe winter. It is the primarypest in the Grande RondeValley and central Oregon.

• The sod webworm or cran-berry girdler (Chrysoteuchiatopiaria) is a well-knownpest of Kentucky bluegrass,

as well as other grasses, inthe Pacific Northwest(Crawford and Harwood,1959; Kamm, 1971a). It isconsidered the most severepest on bluegrasses andcreeping fescue in northeastWashington (Harwood,1958).

• The cutworm Protagrotisobscura is a major pest ofgrasses grown for seed in thePacific Northwest, espe-cially in the Grande RondeValley (Kamm, 1982). Theglassy cutworm (Crymodesdevastator) was found inlarge numbers near Spokanein a survey of grass seed

Marvin D. Butler, Extension cropscientist, Oregon StateUniversity; Steve C. Alderman,National Forage SeedProduction Research Center,Corvallis; Paul C. Hammond,Entomology Department,Oregon State University; RalphE. Berry, EntomologyDepartment, Oregon StateUniversity; William J. Johnston,Department of Crop and SoilSciences, Washington StateUniversity; and Craig R.McNeal, field representative,Blue Mountain Seed, Imbler, OR.

fields (Crawford andHarwood, 1959). It isconsidered the primarycutworm pest in that area(Harwood, 1958). Cutwormdamage frequently occurs infall and may continuethrough winter and intospring. Cutworms can causesignificant damage byfeeding on the crowns ofdeveloping plants (Kamm,1982).

• Thrips (e.g., Anaphothripsobscurus) (Kamm, 1971b)and fly larvae of the genusChloropidae (Starks andThurston, 1962) can causesilvertop. Silvertop refers tobleached, whitish, or silver-colored dead panicles,resulting from damage to thepanicle stalks. Grass seedfields occasionally aretreated to control thrips(Anaphothrips spp. andAptinothrips spp.) and otherpotential pests such asleafhoppers (cicadellids) andthe English grain aphid(Sitobion avenae).

• A grass bug (Labopshesperius) is considered aminor pest but has beenreported to cause seriousdamage to grass leaves inseed fields near Spokane(Harwood, 1958).

Ergot on Kentuckybluegrass

In addition to insect pests,Kentucky bluegrass often isinfected with ergot, a diseasecaused by the fungus Clavicepspurpurea (Alderman et al.,

1998). Host seed is replacedwith a hard black body (sclero-tium) about one to four timeslarger than normal seed (Alder-man, 1991; Barger, 1931;Bove, 1970). Both the diseaseand the sclerotium are com-monly referred to as ergot.

Most cultivars of Kentuckybluegrass are susceptible toergot, although some are moresusceptible than others. Rain-fall or irrigation at the time offlowering promotes the devel-opment of ergot. High soilmoisture conditions support thedevelopment of fruiting bodiesand subsequent production andrelease of spores (ascospores).The tiny, threadlike ascosporesmove through the air like fineparticles of dust, easily carriedby the slightest air current.Ascospores that contact flowerstigmas germinate and infectthe flowers.

During infection of Ken-tucky bluegrass flowers byC. purpurea, plant sap exudesfrom the infected ovaries(Luttrell, 1980). This exudate iscommonly referred to as"honeydew" because of its highsugar content (Barger, 1931;Bove, 1970; Mower andHancock, 1975). Clavicepsinterferes with the normalwound-healing process thatoccurs when plant tissues arecut or damaged. The result iscontinuing seepage of sapthrough the infection site.

The honeydew containslarge numbers of fungal spores(conidia) that are produced onthe surface of the ovary duringthe early stages of infection.

Conidia are released andaccumulate in the plant sap asit leaks from the woundedovaries, accumulating in largedrops.

Insects are believed to playa role in the spread of ergot(Atanasoff, 1920; Morenoet al., 1971; Ingold andPlunkett, 1979; Lemon, 1992)as they feed on conidia-containing honeydew. Thesweet syrup is especiallyattractive to flies (Atanasoff,1920; Barger, 1931; Ingold andPlunkett, 1979; Lemon, 1992),wasps (Polistes spp.) (Hardy,1988), and nocturnal moths(Moreno et al., 1971). Thepresence of conidia in thehoneydew makes it no lessattractive to insects.

During feeding, conidia areconsumed by the insects andpass intact through theirdigestive tract, with no appar-ent harm to the insect. Honey-dew and conidia also stick tomouthparts, legs, and otherbody parts. When insects thenland on healthy flowers, theycan transfer conidia to theflower stigmas or ovary,providing opportunity for newinfections and, in turn, newsources of honeydew. Thisassociation is of mutual benefitto the insect and the fungus.

Methods andmaterials

Kentucky bluegrass fieldsin the Rathdrum Prairie, Idaho;central Oregon; and the GrandeRonde Valley, Oregon, weresampled for insects, ergot

2 • Insects and Ergot in Kentucky Bluegrass Seed Production Fields in the Pacific Northwest

sclerotia, and honeydew from1996 to 1998. Three Kentuckybluegrass seed fields in eachregion were sampled during1996 and 1997. In two of theregions in 1998, only two fieldswere sampled. Fields weresampled 1 week or less beforeharvest to coincide with peakoccurrence of ergot sclerotiaand honeydew.

Varieties sampled each yearon the Rathdrum Prairie were`Shamrock,' `Midnight,' and`Plush.' In central Oregon,`Coventry' and 'Gnome' weresampled in 1996; 'Coventry,'`Georgetown,' and 'Merit' in1997; and 'Georgetown' and`Coventry' in 1998. In theGrande Ronde Valley, thevarieties sampled included`Bristol' and 'Coventry' in1996; `Sidekick,' `Nassau,' and`Ascot' in 1997; and 'Fairfax'and 'Nassau' in 1998.

Insect collection andidentification

Insects were sampled witha sweep net, an aphid sampler(Gray and Schuh, 1941), anduniversal black light traps.Most of the insects werecollected with a 14-inch sweepnet. Insects collected by boththe sweep net and aphidsampler were taken from eachof four quadrants in each field.A representative series ofindividuals of each insectspecies collected was pinnedand identified with the locationand date of collection.

The aphid sampler wasused to collect small insects

from grass heads and foliage.The aphid sampler consisted ofa cylinder (16 inches in diam-eter x 20 inches tall) with ahandle on each side near the lidfor shaking. Grass foliage wasplaced on an 0.25-inch meshscreen inside the shaker andexposed to methyl ethyl ketoneto relax the insects and make iteasier to separate them fromthe foliage during shaking.

Insects were collected in ajar at the base of the shaker andtransferred to vials containingethyl alcohol. Insects wereidentified, and the number ofspecimens of each species wasrecorded.

Moths were sampled with asingle black light trap placed100 feet from the edge of eachfield at dusk. Moths werecollected the following morn-ing. A Bio-Strip fumigant strip(2.5 inches x 6.5 inches)impregnated with dichlorvoswas placed in the bottom of thetraps to kill the moths. Speci-mens were mounted andidentified.

Sampling Kentuckybluegrass for ergot

Grass seed heads werecollected during 1997 and 1998to determine the amount ofhoneydew and ergot sclerotiapresent in each field. Using afinger knife, 100 samples ofgrass panicles were randomlycollected by hand from a singlearea (100 feet x 100 feet) ineach field. The total number ofsclerotia per sample, thepercentage of panicles with

honeydew, and the percentageof panicles with sclerotia wererecorded.

Detecting ergot on insectsTo quantify the association

of insects and ergot, a secondcollection was made at eachsite using a modified sweep netand aphid sampler. In bothcases, sticky cards were used toprevent cross contaminationand enable individual insects tobe evaluated for the presenceof ergot honeydew and conidia.

The sweep net was modi-fied with a sticky card mountedat the end of a handle andenclosed in an 0.25-inch meshhardware cloth cylinder10 inches in diameter. Insectspassed through the mesh andwere collected on the stickycard, permitting sweeps to betaken without contaminationby foliage and associatedhoneydew.

The modified aphid sam-pler consisted of a sticky cardin the bottom of a straight-sided 5-gallon plastic bucketwith a collecting jar at thebottom. This allowed indi-vidual insects to fall directlyonto the sticky card.

For moth collection, twosticky cards were attached tothe outer edge of the collectionbucket so that individuals couldbe collected as they approachedthe black light trap.

For ergot assessment, adrop of water was placed onthe mouthparts of insectsattached to the sticky cards towash off any conidia. The dropwas removed, mounted on a

Insects and Ergot in Kentucky Bluegrass Seed Production Fields in the Pacific Northwest • 3

glass slide and examined forergot conidia. Since speciesidentification on sticky cardswas difficult, insect identifica-tion to the species level was notattempted.

ResultsInsects collected

Of the 30 species of insectscollected in sweep nets and theaphid sampler, 4 were pests orpotential pests on grass seed,10 were beneficial, and15 were classified as casualvisitors or pests on other crops(Table 1). Pests or potentialpests on Kentucky bluegrassseed included the sod web-worm, aphids, thrips, andleafhoppers. The sod webwormwas the only serious insect peston grasses that was collected insweeps from all three locations.

Beneficial predatorsincluded the lady beetle(Hippodamia spp.), minutepirate bug (Orius tristicolor),big-eyed bug (Nysius spp.),damsel bug (Nabis spp.), andcommon green lacewing(Chrysoperla plorabunda).Parasitic insects includedbraconid and ichneumonwasps. The most abundantbeneficial insects collected insweep nets across the threeregions were big-eyed bugs,damsel bugs, ichneumonwasps, and lady beetles.

The average number ofaphids, leafhoppers, and thripscollected from grass foliagesamples in the aphid samplerwas relatively low acrosslocations and years (Table 2).On the Rathdrum Prairie,

leafhoppers and thrips werecollected in the greatest num-bers; in central Oregon, thripswere most common; and lownumbers of aphids and leafhop-pers were collected in theGrande Ronde Valley. How-ever, the number of thripscollected in the Grande RondeValley in 1998 (184) may raiseconcerns about silvertop. Thenumber of aphids generallywas less than the number ofleafhoppers or thrips.

Night-flying mothsincluded grass-feeding cut-worms (Table 3). Protagrotisobscura was the most commoncutworm species of thoseknown to be pests in grassesgrown for seed, and it waspresent in all sampled fields.Significantly different cutwormcomplexes were collected fromthe three growing areas. Forexample, Agroperina dubitanswas collected from all fields inIdaho, but from only one fieldin Oregon. The glassy cutworm(Crymodes devastator) wascommon in samples from theOregon sites, but was found atonly one field in Idaho.

Presence of ergot andhoneydew on insects andKentucky bluegrass

The amount of ergotsclerotia and honeydew ongrass panicles varied amongfields (Table 4). The number ofsclerotia per 100 paniclesranged from zero to 565, andergot was found in all fieldsexcept on the variety`Georgetown' in 1998(Table 4).

Ergot conidia were foundon 40 to 100 percent of moths(Table 4). In 13 of 15 collec-tions, the percentage ofmoths with conidia exceeded67, indicating a strong associa-tion between moths and ergot.Conidia also were found onflies, leafhoppers, and thrips.

DiscussionInsect—ergot relationships

A relationship between thepresence of ergot in a field andthe percentage of moths, flies,leafhoppers, or thrips withergot conidia was not estab-lished. Fields with higherlevels of ergot did not necessar-ily have insect populations withhigh levels of ergot orhoneydew.

Insect populationsA rich diversity of insects

was collected in grass fields atall three locations (Table 1).The majority of insects werecollected using the sweep net.However, aphids, thrips, andleafhoppers were collectedmore effectively using theaphid sampler, and moths(other than the sod webworm)were collected at night withuniversal black light traps.

Results from this projectand discussions with industryrepresentatives suggest thereare significant differences ininsect pests among the threegrowing areas. The wintergrain mite, cutworms, and thesod webworm are importantpests on grass fields in theGrande Ronde Valley. The

continues on page 8


Table 1.—Number of fields in which each insect type was collected with a sweep net.Rathdrum Prairie, ID Central Oregon Grande Ronde Valley, OR

1996 1997 1998

3 fields 3 fields 3 fields

1996 1997 1998


1996 1997 1998


Common pests on grass seedButterflies, moths (Lepidoptera)

Sod webworm (Pyralidae) 3 3 3 2 1 0 1 1 3

Beneficial predators and parasitesBeetles (Coleoptera)

Ground beetle (Carabidae) 0 0 1 0 0 0 0 0 0Lady beetle (Coccinellidae) 2 2 2 3 1 2 0 1 1Rove beetle (Staphylinidae) 0 0 0 1 0 0 0 0 1

True bugs (Heteroptera)Minute pirate bug (Anthocoridae) 0 2 0 0 0 0 0 0 0Big-eyed bug (Lygaeidae) 3 1 3 3 2 2 3 3 2Damsel bug (Nabidae) 3 0 2 3 3 2 3 2 2

Wasps, bees, ants (Hymenoptera)Braconid wasp (Braconidae) 2 0 0 1 0 1 2 0 0Ichneumon wasp (Ichneumonidae) 1 3 3 1 3 1 2 3 3

Lacewings (Neuroptera)Green lacewing (Chrysopidae) 0 0 0 1 0 0 0 0 0

Damselflies, dragonflies (Odonata)Damselfly (Coenagrionidae) 0 0 0 1 0 0 0 1 0

Casual visitors/pests on other cropsBeetles (Coleoptera)

Seed beetle (Bruchidae) 0 0 1 o 0 0 0 0 0Leaf beetle (Chrysomelidae) 0 1 0 0 0 0 1 2 1

Flies (Diptera) 3 3 3 3 3 2 3 3 2True bugs (Heteroptera)

Plant bugs (Miridae)Calocoris 0 0 1 o o 0 0 0 0Hoplomachus 2 3 2 o o 0 0 0 0Lygus 2 0 0 1 1 0 0 1 0Megaloceroea 1 3 1 1 0 0 0 1 0Monosynamma 1 3 3 o 0 0 1 1 0Stenodema 0 2 0 0 0 0 0 3 1

Stink bug (Pentatomidae) 0 2 1 0 0 0 0 0 0Scentless plant bug (Rhopalidae) 0 0 0 2 0 0 1 0 0Shield-backed bug (Scutelleridae) 2 2 3 0 0 0 0 2 1

Planthoppers (Homoptera)Froghopper (Cercopidae) 0 1 3 0 1 0 0 0 1Delphacid planthopper

(Delphacidae) 0 0 2 1 2 1 1 1 1Grasshoppers, katydids (Orthoptera)

Grasshopper, katydid (Acrididae) 2 0 0 0 0 1 2 0 1


Table 2. Average number of insects per sample from Kentucky bluegrass foliage extractedin sampling can.

Number of individuals collected per sample

Rathdrum Prairie, ID Central Oregon Grande Ronde Valley, OR

1996 1997 1998 1996 1997 1998 1996 1997 1998

3 fields 3 fields 3 fields 3 fields 3 fields 2 fields 3 fields 3 fields 2 fields

Aphids, leafhoppers (Homoptera)Aphid (Aphididae) 0.8 1.6 1.2 1.1 4.6 1.8 2.5 0.9 2.5Leafhopper (Cicadellidae) 6.7 37.3 15.5 1.1 4.0 1.1 4.7 24.1 5.8

Thrips (Thysanoptera)Thrips (Thripidae) 1.1 25.1 13.8 0.5 40.3 30.1 0.1 48.3 184.1

Table 3. Number of fields in which each species of grass-feeding cutworm moths wascollected in black light traps.

Soil-surface cutworms

Rathdrum Prairie, ID Central Oregon Grande Ronde Valley, OR

1996 1997 1998


1996 1997 1998

1 field 3 fields 2 fields

1996 1997 1998


Protagrotis obscura 2 3 3 1 3 2 2 3 2Agroperina dubitans 2 3 3 0 0 0 1 0 0Crymodes devastator 0 0 1 1 2 2 1 1 0Apamea amputatrix 0 0 0 0 0 1 2 1 0Chortodes rufostrigata 0 0 0 0 0 2 0 0 0Apamea alia 0 0 0 0 0 0 0 0 1Agroperina lateritia 0 0 0 0 0 0 1 0 0

Climbing cutwormsAletia oxygala 0 0 0 1 0 0 2 2 2Leucania farcta 0 0 0 1 1 1 1 0 0


Table 4.—Association of ergot conidia with various insects collected from Kentuckybluegrass fields during 1997 and 1998 and level of ergot present in the fields.

Sclerotiaper 100

panicles'

Percent paniclesPercentage of insects with ergot conidia

Moths Flies Leafhoppers ThripsSclerotia Honeydew % Total2 % Total % Total % Total

Rathdrum Prairie, ID1997

`Shamrock' 20 12 7 67 (6) 75 (4) 19 (505) 14 (28)`Plush' 65 26 32 80 (10) 63 (8) 60 (216) 32 (142)`Midnight' 151 55 0 81 (16) 35 (23) 13 (15) 6 (66)

1998`Shamrock' 27 15 6 100 (16) 74 (19) 20 (329) 10 (99)`Plush' 18 9 2 91 (11) 57 (37) 25 (188) 16 (108)`Midnight' 88 33 4 67 (6) 24 (37) 7 (59) 3 (97)

Central Oregon1997

`Coventry' 212 51 4 100 (3) 52 (23) — — 17 (6)`Merit' 122 49 64 100 (16) 69 (70) 42 (12) 34 (29)`Georgetown' 3 1 0 — 11 (9) 0 (15) 3 (96)

1998`Coventry' 565 87 0 67 (15) 37 (402) 4 (24) 4 (237)`Georgetown' 0 0 0 40 (5) 19 (32) — 6 (17)

Grande Ronde Valley, OR1997

`Ascot' 42 21 1 89 (66) 73 (15) 57 (28) 31 (39)`Nassau' 82 31 22 84 (37) 14 (7) 10 (51) 0 (2)`Sidekick' 4 2 0 100 (31) 60 (5) 39 (28) 6 (16)

1998`Fairfax' 206 73 30 87 (31) 77 (160) 51 (69) 16 (318)`Nassau' 12 8 1 43 (14) 32 (327) 22 (68) 8 (247)

'Number of ergot sclerotia based on single 100-panicle sample per field.2Total number of individuals examined.


winter grain mite is the majorpest in central Oregon, with thesod webworm only occasion-ally reaching treatable levels.On the Rathdrum Prairie, thesod webworm is considered theonly major insect pest.

Aphids were not found tobe an economically importantpest during the course of thisstudy (Table 2), but the Englishgrain aphid (Sitobion avenae)was found in fields in all threeregions. Although not normallyconsidered a pest of grasses,this aphid can cause economicinjury to cereals in some years.

Anaphothrips spp. andAptinothrips spp. seemed to bethe most common genera ofthrips collected. Both can causesilvertop symptoms whenpopulations feed within the"boot" as the seed head isdeveloping. However, numberscollected generally were low(Table 2) compared to numberscollected in bentgrasses andfine fescue grasses of westernOregon (Kamm, 1971b), andthese pests seemed to be oflittle significance.

Plant bugs (Stenodemaspp.) also are known to causesilvertop (Arnott and Bergis,1967). They were collected inlow numbers on the RathdrumPrairie and in the GrandeRonde Valley, but were absentfrom central Oregon samples.

Silvertop was not a prob-lem in the fields sampled, buthas been reported to occur inKentucky bluegrass in theNorthwest (Crawford andHarwood, 1959; Kamm,1971b).

Flies were the only casualvisitor or pest of other cropsthat were found consistently inany significant number inKentucky bluegrass fieldsacross the three regions. Otherinsects considered casualvisitors or noncrop pestsincluded grasshoppers, seedand leaf beetles, and a varietyof plant bugs.

The diversity of night-flying moths varied substan-tially between the RathdrumPrairie, central Oregon, and theGrande Ronde Valley (Table 3).P obscura was collected fromevery field across the threegrowing regions. A. dubitanswas common only on theRathdrum Prairie and, alongwith P. obscura, was the onlymoth species collected in thatarea, with the exception ofglassy cutworms (C. devasta-tor) found in one field.

There was much morediversity in Oregon, where ninespecies of grass-feeding mothswere collected; six of thesewere found in central Oregonand eight in the Grande RondeValley (Table 3). Of the speciescollected, seven were soil-surface feeding cutworms,while two were climbingcutworms, which often feed onflowers and seed heads(Crumb, 1956; Kamm, 1982).Only soil-surface feedingcutworms were found at theIdaho site, and they were themost abundant cutworm at theOregon sites (Table 3).

obscura, a generalizedcutworm that often isextremely abundant in

agricultural areas throughoutthe Northwest, was collected atevery site in this study. How-ever, it is scarce or absent insurrounding natural habitats. Ina subsequent quantitative studyof grass-feeding cutworms inKentucky bluegrass seedfields in central Oregon and theGrande Ronde Valley,P. obscura made up99.4 percent of the 30,000moths collected (Butler andHammond, 2001). The remain-ing 0.6 percent included 11different species.

A preliminary comparisonof burning and nonburningresidue management conductedin the Grande Ronde Valleyindicated a 64 percent reduc-tion in P. obscura populationsthe year following open fieldburning (Butler and Hammond,2002).

This study indicates thatbluegrass seed productionoccurs in an environmentfriendly to beneficial preda-ceous and parasitic insects.Relatively few insect pests areassociated with bluegrass seedproduction. Most routineinsecticide applications aremade in late fall, with applica-tions possible through earlyspring, a time when beneficialinsects are less active. Popula-tions of beneficials increase inthe absence of insecticidesduring late spring through earlysummer, negating the need forinsecticide applications duringdevelopment and maturity ofKentucky bluegrass seed. Theavoidance of pesticides duringlate spring to summer not only


increases populations ofbeneficials but provides ahabitat that facilitates anecologically desirable increasein insect diversity overall.

The moth Chortodesrufostrigata, a casual visitorcollected in fields at bothcentral Oregon locations during1998, previously had beencollected only in wet meadowsin the Blue and Wallowamountains of northeast Oregonand in one isolated case inLake County in south-centralOregon. These first-timecollections in central Oregonindicate a significant rangeextension for this specieswithin Oregon. Quite possibly,the irrigation of bluegrass seedfields duplicates the normalwet meadow habitat of thisspecies, allowing a naturallyvery rare species, whichnormally inhabits mountainmeadows, to invade andsuccessfully establish inirrigated grass seed fields atmuch lower elevations.

Central Oregon bluegrassfields occupy areas that for-merly were a sagebrush-bunchgrass habitat, but mothsthat normally live in this nativehabitat were not found in thegrass fields. The replacementof native desert with irrigatedbluegrass fields has resulted ina total replacement of nativecutworm moths. With theexception of P. obscura, all ofthe grass-feeding moths col-lected are typical of moisthabitats and are common athigher elevations of the BlueMountains and Cascade Range.

It is interesting to note thesimilarities between Kentuckybluegrass seed production anda mountain meadow habitat.Common elements generallyinclude adequate water throughseed set, with moist conditionsand a large amount ofvegetative production. In bothsituations, the grass is allowedto produce seed and then drydown during mid- to latesummer, followed by fall rains(or late-summer irrigation) andcold winters.

ConclusionsKey findings from this

project include the following.• A large diversity of insects is

present in Kentucky blue-grass fields in the PacificNorthwest, most of whichare casual visitors or benefi-cial insects.

• Pests or potential pests varyamong growing areas. Pestsinclude the sod webworm,cutworms, and winter grainmites. Aphids, thrips, andleafhoppers are potentialpests.

• Protagrotis obscura was byfar the dominant cutwormspecies collected.

• Ergot sclerotia and honey-dew were found in nearly allthe fields sampled, and ergotconidia were collected frommoths, flies, leafhoppers,and thrips. However, arelationship between thelevel of ergot infection in thefield and the number ofinsects carrying ergotconidia was not established.

• Silvertop was not a factor inthe fields sampled, andgenerally low levels of thethrips that cause the symp-toms were collected.

• The moth Chortodesrufostrigata, collected incentral Oregon fields,previously had beencollected only from moun-tain meadows in the Blueand Wallowa mountains ofnortheast Oregon and fromLake County in south-central Oregon. It is notconsidered a potential pest.

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© 2002 Oregon State University. This publication may be photocopied or reprinted in its entirety for noncommercial purposes.

This publication was produced and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Extensionwork is a cooperative program of Oregon State University, the U.S. Department of Agriculture, and Oregon counties.

Oregon State University Extension Service offers educational programs, activities, and materials—without discrimination basedon race, color, religion, sex, sexual orientation, national origin, age, marital status, disability, or disabled veteran or Vietnam-era veteran status. Oregon State University Extension Service is an Equal Opportunity Employer.

Published September 2002.

insects and ergot in kentucky bluegrass seed production fields in the pacific northwest

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