Leafhopper host plant associations for Anagrus parasitoids (Hymenoptera: Mymaridae) in the Okanagan Valley, British Columbia

2007·3.9 MB·English

by  D Thomas Lowery

J.Entomol. Soc. Brit.Columbia 104,December2007 9
Leafhopper host plant associations for
Anagrus parasitoids (Hymenoptera: Mymaridae)
in the Okanagan Valley, British Columbia
D. THOMAS L0WERY\ SERGUEI V. TRIAPITSYN^
and GARY J.R. JUDD^
ABSTRACT
Anagrus spp. are importantnatural regulators ofleafhoppers infesting grapes, tree fruits,
and other crops in south central British Columbia (BC). Predominantly four species of
these egg parasitoids, A. atomus (L.), A. avalae Soyka, A. daanei Triapitsyn, and A.
erythroneuraeTriapitzyn andChiappini, werereared fromdormanthostplants and from
summerhostplants in the Okanagan Valley. The largestnumbers ofAnagrus specimens
were collected from roses, Rosa spp; blackberry, Rubus spp; apple, Malus domestica;
and other members ofthe rose (Rosaceae) family. Species ofmint, family Lamiaceae,
were important host plants for several species, with lavender, Lavendula angustifolia,
and garden sage, Salvia officinalis, being both a summer andwinterhost plant for some
species. The most likely leafhopperhost on theseplants is the mint leafhopper,Eupteryx
melissae Curtis. This study contributes to ourknowledge ofthe biology ofAnagrus spe-
cies in south central BC and could contribute to future efforts to preserve or enhance
populations ofthesebeneficial insects.
KeyWords: Mymaridae,Anagrus, parasitoids, leafhoppers,planthosts
INTRODUCTION
Egg parasitoids of the family Mymari- the importation of Anagrus avalae Soyka
dae (Hymenoptera) include the smallest from New Zealand [Vidano and Arzone
known insects (Chiappini and Huber 2004). 1982 - misidentified as Anagrus armatus
Despite being important in natural control nigriventris Girault (Triapitsyn 2001)].
ofleafhoppers (Cicadellidae) and planthop- Their potential as highly effective natural
pers (Delphacidae), they have been under- control agents merits further study of their
utilized in biological control programs as a biology, ecology and leafhopper host asso-
result of their minute size, difficulties in ciations (Agbokaetal. 2004).
their identification and handling (Huber Taxonomic revisions of Anagrus
1986), and their poorly known biology. (Chiappini 1989, Chiappini et al. 1996,
Species ofAnagrus Haliday have been used Triapitsyn 1998), have greatly improvedthe
successfully, however, to control leafhop- reliability of taxonomic and biological in-
pers on apple,Malus domestical rice, Oryza formation on these important regulators of
sativa; grapes, Vitis sp.; and greenhouse leafhopper populations. Until recently it
crops (Vidano et al 1987, Chiappini et al. was thought that eggs of all the grape-
1996, Triapitsyn and Teulon 2002, Agboka feeding Typhlocibinae in North America
et al. 2004). For example, Edwardsiana (NA) were attacked by the same species,
froggatti (Baker), native to Europe, was a Anagrus epos Girault. Differential parasit-
serious pest of apple in Tasmania, Austra- ism rates where two species ofleafhoppers
lia, until it was brought under control with co-occurred on grape led to the suspicion
'AgricultureandAgri-FoodCanada,4200Hwy97, Box5000, Summerland,BC VOH IZO
^DepartmentofEntomology,UniversityofCalifornia,Riverside,CA,92521-0314,USA
10 J.Entomol. Soc.Brit.Columbia 104,December2007
WGL
that A. epos consisted of several biotypes, Erythroneura ziczac Walsh, and in
and Pickett etal. (1987) assumed that some vineyards in the Okanagan and Simil-
ofthese were true species. Anagrus epos is kameen Valleys, British Columbia (BC),
now known to consist of several species (DTL, unpublished data) with the goal of
(Trjapitzin and Chiappini 1994, Triapitsyn preserving and possibly increasing popula-
1995, Chiappini et a/.1996, Triapitsyn tions ofAnagrus parasitoids. These parasi-
1998), withA. erythroneurae Trjapitzin and toids overwinter as immature stages within
Chiappini being the most common egg the eggs of alternate leafhopper hosts
parasitoid of the western grape leafhopper (Williams 1983), while the leafhopperpests
(WGL), Erythroneura elegantula Osbom, ofgrapes spend the winter as adults. Thus,
and the variegated leafhopper, E. variabilis the availability of suitable overwintering
Beamer, in California (Trjapitzin and and early spring leafhopper hosts plays an
Chiappini 1994). Specimens of A. important role in the biology of Anagrus
erythroneurae were identified from as far parasitoids and their ability to control leaf-
north as Wenatchee, WA, but there are few hoppers on grape. This paper reports on the
records of this species from Canada rearing of Anagrus adults from a wide
&
(Trjapitzin Chiappini 1994, Triapitsyn range ofplants that served as hosts forother
1998). species of leafhoppers utilized by these
In 1998 we began to research parasitism parasitoids.
of Virginia creeper leafhopper (VCL),
MATERIALS AND METHODS
Between February and June of 1999 to mology Research Museum, University of
2003, dormant plant hosts potentially con- California, Riverside. Adult Anagrus were
taining overwintering Anagrus in their host also collected from leafhopper-infested
eggs were gathered throughout the leaves of grape and other summer hosts.
Okanagan Valley and placed in sealed, Leaves or stems were placed in distilled
waxed corrugated cardboard boxes in the water in small flasks (50 ml) with the tops
laboratory at room temperature. Anagrus of the flasks sealed as much as possible
spp. emerging from these woody prunings with parafilm. The cuttings were then
were collected in two glass vials (32 ml) placed inside two large waxed paper cups
screwed into holes cut with cork borers into (900 ml, Dixie Cup™, Norwalk, CT) fas-
the upper side ofeach box. Specimens were tened securely together and with a single
preserved in 70% ethanol and shipped to collection vial (8 ml) fastened into a hole
the University of California, Riverside, for cut into the upper end ofone cup. In total,
identification by one of us (S.V.T). Prop- 211 collections were made, including 76
erly point- and slide-mounted voucher plant species.
specimens were then deposited in the Ento-
RESULTS AND DISCUSSION
More than 2,000 Anagrus emerged and lected about 31 Anagrus per 100 cm ofdor-
were identified from dormant and summer mant wood, compared with 4.4 per 100 cm
host plants, with nearly halfthe specimens for blackberry, Rubus spp., and less than 1
emerging from dormant roses, Rosa spp. per 100 cm for plum, Prunus domestica.
(Table 1). Roses were sampled most inten- We successfully rearedAnagrus from 22 of
sively, 20 of 211 total collections of plant 76 plant species sampled over the course of
material, but they also harboured large this study. The predominant species from
numbers ofparasitoids. For cultivated roses all hosts were A. atomus (L.), A. avalae, A.
heavily infested with leafhoppers, we col- daanei Triapitsyn, and A. erythroneurae
)
J.Entomol. Soc.Brit.Columbia 104,December2007 11
Table 1.
Plantspecies in the Okanagan Valley, British Columbia, thatservedaswinter(W) orsummer
(S) leafhopperhosts fromwhichAnagrus eggparasitoids (numbers inparentheses) emerged.
Numbers inparentheses followingthe samplingseason (WorS)refertothenumberofsites
andnumberoftimes eachhostplantwas sampled.
Plantfamily Common name Season Anagrusspecies
iN-Ose ^^xvobdceac) l^UlllValwUlU^C,l\USU i>p. VV yj, 1 CliOrnUS J), uvuiueyj),
erythroneurae(~76)
w
VVIICIlUaC,IvU^Cl op. VV \(l1, i\(^y/\ ULOnlUS y Z.O1j, UVCllCiey^J,
w CIy1111L/IICIAI y LJJf
RlarkhpiTV find Trivherrv C5 in ntofyiu^ prvthrnnpvrnp
Rubus spp. (-15)
oweeicnerry,rruniis civiurn
Choke cherry,P. virginiana wVVj ((7n, 1111)\ atomus (~1U), avalae(~1U1),
dnnnpi
w
Cultivatedplum,P. dotncs- VV rs 9y) erythroneurae(9)
tica
W
Apple,Malus domestica (3, 7) atomus (6), avalae (1),
erythroneurae(24)
Strawberry,Fragariax S(l,l) atomus orerythroneurae(10)
ananassa
Dogwood Redosierdogwood, Cornus W(3,3) erythroneurae(1)
stolonifera
Redosierdogwood, Cornus S (4, 7) daanei (1?), erythroneurae (3)
stolonifera
Willow Willow sp.,Salixsp. W(3, 10) nearnigriventrus (1),Anagrus sp.
(Salicaceae) (t9ew)
l-yUlUL/Cdll WllllC' UllCll, UlUfnU^ \^)
(Betulaceae) Betulapendula
w n
AV^fltPfbirph /? nrri/ipntnli VV J5)^ nLlfLniJrfyrjl'iljdsiJ:(\A*\)f niAvVLnlLJLnlCp- (\114"^1,
erythroneurae(3)
W
Alder,Alnus sp. (3, 3) erythroneurae(1)
W
Maple Douglas maple,Acer (4, 6) atomus (1)
(Aceraceae) glabrum
Elm(Ulmaceae) Siberian eim, Ulmuspumila ""W(4;'6r atomus(4)
Grape (Vitaceae) Grape, Vitis vinifera S (5, 6) daanei(348)
Virginiacreeper,Partheno- S (2, 3) daanei(15)
cissusquinquefolia
Mint Catnip,Nepeta cataria S (6, 11) atomus(217), erythroneurae (7)
(Lamiaceae)
(=Labiatae) Persiancatmint,Nepetax S (1, 2) atomus(~26), erythroneurae
mussinii (-15)
Gardenmint,Mentha sp. S (1, 1) atomus(6), erythroneurae(2)
Mintsp.,Mentha sp. S (1, 1) atomus (5), erythroneurae(1)
Lavender,Lavendula W(l, 1) atomus {A)
angustifolia
W
Garden sage,^a/v/a (1, 1) atomus(~33), erythroneurae
officinalis (-27)
12 J.Entomol. Soc.Brit.Columbia 104,December2007
(Table 1). The only othQTAnagrus collected Curtis, occurs on these plants in southern
were a single probable specimen ofA. ni- BC (Beime 1956), andthis is the likelyhost
griventris Girault, and an unknown species for A. atomus during the summer on these
fromwillow {Salix sp.). plants. It may be the first overwintering
The common and widespread European record for a species ofAnagrus on plants in
species, A. atomus, which also occurs in this family.
South America and Asia (Triapitsyn 2001), Anagrus erythroneurae is clearly the
was the most commonly collected species most important egg parasitoid ofWGL and
(Table 1). It was identified from 16 host the variegated leafhopper on grapes in Cali-
plants from six families. Most of our host fornia and Baja California Norte, Mexico
associations for A. atomus confirm earlier (Triapitsyn 1998). In the Napa and Sonoma
reports (Chiappini 1989, Triapitsyn 1998). Valleys of CA, more than 95% of the egg
WGL
Although it parasitizes the eggs ofleafhop- parasitoids emerging from eggs of
pers on grapes in Europe and Asia, all were A. erythroneurae. Triapitsyn (1998)
Nearctic records are from plants other than also reported it from apple infested with the
those in the Vitaceae. We also failed to white apple leafhopper and from plum in-
obtain A. atomus from grapes; most ofour fested with the plum leafhopper. A.
records were from roses; blackberry, Rubus erythroneuraewas recognizedonlyrecently
sp.; choke cherry, Prunus virginiana; and as a new species (Trjapitzin and Chiappini
apple. Material examined by Triapitsyn 1994) and its host associations and biology
(1998) included specimens collected from are not well known. Many previous reports
WGL
apple and rose in the Okanagan Valley by referring to the effective control of by
McKenzie (1973). Reported leafhopper A. epos can likely be attributed to A.
hosts for A. atomus associated with these erythroneurae (Chiappini et a/.1996). Ana-
host plants include the white apple leafhop- grus erythroneurae is known to parasitize
per, Typhlocyba pomaria McAtee, and the eggs ofa number ofleaftiopper species,
green apple leafhopper, Empoasca maligna most of which belong to the genera
Walsh, on apple; the rose leafhopper, Ed- Erythroneura Fitch, Dikrella Oman, and
wardsiana rosae (L.), on rose and black- Typhlocyba Germar. Not all species within
berry; and the plum leafhopper, E. pruni- these genera are suitable hosts, however.
cola (Edwards), onplum(Triapitsyn 1998). We did not rear A. erythroneurae from
Given their size and abundance, trees in leaves of grapes or Virginia creeper vines,
the birch (Betulaceae), maple (Aceraceae) Parthenocissus quinquefolia, infested only
and elm (Ulmaceae) families should be with VCL (Table 1). In BC, the rose leaf-
considered important overwintering plant hopper overwinters as eggs in the stems of
hosts for this species. Yet only a small rose and blackberry, and this is the likely
number ofA. atomus were collected from host on these plants. The early spring and
dormant twigs from plants in these families summer host on plants ofthe mint family is
(Table 1). Maple, alder and birch support a likely the mint leafhopper. Other potential
number of leafhopper species (Hamilton summer host plants are strawberry, Fra-
1985). The likely host for A. atomus on garia x ananassa, and red osier dogwood,
Siberian elm, Ulmus pumila, is Empoasca Cornusstolonifera (Table 1).
bipunctata (Oshanin), as it was the only Our sampling of potential winter and
speciesreportedby Hamilton (1985) to feed spring hosts resulted in rearings of A.
on Siberian elm inBC. Largenumbers of^. erythroneurae from 14 plant species (Table
atomus were collected in summer from sev- 1). Overwintering A. erythroneurae were
eral species of plants in the mint collected primarily from roses, blackberry,
(Lamiaceae) family, and it was also col- and plum. Members of the birch family
lected from sage. Salvia officinalis, and have not been recorded previously as over-
lavender, Lavendula angustifolia, in March. wintering host plants, and we do not know
The mint leafhopper, Eupteryx melissae which leafhopper species are being parasi-
J.Entomol. Soc.Brit.Columbia 104,December2007 13
tized by A. erythroneurae on these trees. Anagrus daanei was recognized as a
Anagrus erythronuerae is likely parasitiz- new species only recently (Triapitsyn 1998)
ing eggs ofthe mint leafhopper on catmint, and there is little unequivocal information
Nepeta x mussinii; catnip, Nepeta cataria; available relating to its winter hosts. It has
garden sage; and garden mint, Mentha spp. been collected from eggs of leafhoppers
NA
Additional research is required to identify infesting grapes in (Triapitsyn 1998)
the leafhoppers on these trees and other andwas the only species we recovered from
host plants used by A. erythroneurae as eggs of VCL (Table 1). Triapitsyn (1998)
winterorsummerhosts inBC. identifiedA. daanei from California associ-
Parasitism by Anagrus erythroneurae ated with dormant blackberry, and from
WGL
might limit the range of the in the eggs ofthe rose leafhopper in dormant rose
Okanagan Valley. Many of the vineyards in New York. We were unable to rear any
on the east side of the Okanagan Valley specimens from dormant blackberry and
south of Penticton are located some dis- rose inBC,perhaps reflecting differences in
tance from apple and Prunus orchards and leafliopper species on these plants in the
few nearby areas support wild roses or two regions. A small number ofA. daanei
blackberry. In California vineyards, some were collected from dormant twigs of
WGL
control of usually occurs near ripar- choke cherry near Armstrong at a location
ian areas supporting blackberry or rose far from commercial vineyards, but not
(Doutt and Nakata 1965, Williams 1983) or from dormant choke cherry at a number of
French prune trees (Kido et al 1984) that sites in the south Okanagan Valley close to
maintain overwintering Anagrus. Reduc- vineyards. Large numbers of parasitoids
WGL
tions in numbers of in Okanagan moving from vineyards in fall might elimi-
vineyards might be achieved by preserving nate nearby alternate leafhopper hosts, or
natural refugia and planting suitable over- there might be differences in leafhopper
wintering (i.e. plum and rose) and early species or abundance between the warmer,
spring (i.e. catmint) hosts, provided that drier south Okanagan and the cooler, wetter
such areas are approximately comparable in north. Several species of leafhopper occur
size to the nearby vineyards and are able to on choke cherry, including four native spe-
sustain viable and sizeable populations of cies of Typhlocyba that occur across the
alternate host leafhopper species. continent (Hamilton 1985).
Anagrus avalae is another common McKenzie (1973) reared what was at
NA
European species recorded in parasitiz- that time believed to be ^. epos from para-
ing eggs ofthe rose leafhopper on rose and sitized eggs of VCL on Okanagan grapes.
white apple leafhopper on apple (Chiappini He described the females as light brown in
and Triapitsyn 1997; Triapitsyn 1998). colour, which is characteristic forA. daanei
McKenzie (1973) collected it from roses in (Triapitsyn 1998). Anagrus were also
the Okanagan Valley. We collected it from reared from dormant branches ofwild rose
dormant twigs ofrose, choke cherry, apple infested with the rose leafhopper and from
and birch (Table 1). Mulla (1956) was able apple infestedwith the white apple leafhop-
to collect this species, incorrectly referred per, but no mention was made as to the col-
to as^. armatus nigriceps Girault, from the our of females from these collections.
summer eggs of plum leafhopper, but not McKenzie (1973) noted that Anagrus para-
from overwintering eggs. Interestingly, sitoids emerging from rose shoots in spring
although it winters in the eggs of leafhop- did so during two distinct periods and
pers on other members of the rose family, speculated that this bimodal emergence
we also did not collect A. avalae from dor- pattern might result from differences in the
mant twigs of plum. This species has not time when eggs were parasitized in fall. In
been recorded parasitizing leafhopper eggs addition toA. erythroneurae, we also reared
on grapes in NA, and we did not rear it A. atomus andA. avalae from dormant rose
fromthisplanthost in BC. shoots. The bimodal emergence noted by
14 J.Entomol. Soc.Brit.Columbia 104,December2007
McKenzie (1973) most likely represented saccharum Marsh.; prickly ash, Zanthoxy-
different emergence times for different spe- lum americana Mill.; black locust, Robinia
cies. pseudoacacia L.; and rambler rose, Rosa
VCL is one ofthe most important pests multiflora Thumb. (Triapitsyn 1998). We
of grapes in south central BC, and sprays did not record A. daanei from these or
are frequently required to prevent economic closelyrelated winterhosts inBC. The rela-
damage. The small number ofwintering A. tive scarcity of VCL in eastern NA vine-
daanei collected during our study reflect yards might be due to greateroverwintering
the low rates ofparasitism ofVCL in most success ofA. daaneiin thatregion.
commercial vineyards. Parasitoids are rare Anagrus tretiakovae, native to eastern
or absent from many vineyards until late in NA, was apparently introduced to Califor-
the season (DTL unpublished) and A. nia in 1987 as a biotype ofAnagrus epos
daanei rarely controls VCL populations Girault to control leafhoppers on grape. We
adequately. InNew York vineyards, in con- did not collectA. tretiakovae from dormant
trast, A. daanei, A. erythroneurae and A. host plants or from grape. This species is
tretiakovae contribute to the biological con- likely to invade BC eventually, but it could
trol ofseveral species ofErythroneura leaf- be considered for intentional importation
hoppers infesting grape (Triapitsyn 1998, for the biological control ofleafhoppers on
Williams and Martinson 2000). Known grape. Detailed rearings of Anagrus spp.
leafhopper hosts forA. daanei on grapes in from leafhopper hosts on their overwinter-
New York include the Eastern grape leaf- ing host plants are needed to confirm host
hopper, Erythroneura comes (Say), VCL, associations and determine which plant
and E. bistrata McAtee (Triapitsyn 1998). species might be used as overwintering
Records from dormant plant hosts in east- refugia aroundvineyards inBC.
em NA include apple; sugar maple, Acer
ACKNOWLEDGEMENTS
Technical assistance was provided by through the Matching Investment Initiative,
Karin Todd, Jocelyn Gartrell, Lisa Wam- the National Research Council of Canada
bold and Lauren Bunckle. Funding for this Industrial Research Assistance Program,
project was providedby the BC Wine Insti- and the BC Investment Agriculture Founda-
tute and Agriculture and Agri-Food Canada tion.
REFERENCES
Agboka, K., A.K. Tounou, R. Al-Moaalem, H.-M. Poehling, K. Raupach and C. Borgmeister. 2004. Life-
table study ofAnagrus atomus, an egg parasitoid ofthe green leafhopper, Empoasca decipens, at four
differenttemperatures.BioControl49: 261-275.
Beime, B.P. 1956. Leafhoppers(Homoptera: Cicadellidae)ofCanadaandAlaska. TheCanadianEntomolo-
gist88, Supplement2.
Chiappini, E. 1989. Review ofthe European species ofthe genusAnagrus Haliday (Hymenoptera: Chalci-
doidea). BollettinodiZoologiaAgrariaediBachicoltura, SerieII21: 85-119.
Chiappini, E. and J. Huber. 2004. Fairyflies (Hymenoptera: Mymaridae), pp. 824-825. In Capinera, J.L.
(Ed.),EncyclopediaofEntomology,vol. 2. KluwerAcademicPress,Dordrecht.
Chiappini, E., S.V. Triapitsyn and A. Donev. 1996. Key to the Holarctic species ofAnagrus Haliday
(Hymenoptera: Mymaridae) with areview ofthe Nearctic and Palearctic (otherthan European) species
anddescriptionofnewtaxa.JournalofNaturalHistory30: 551-595.
Chiappini, E. and S.V. Triapitsyn. 1997. Redescription ofAnagrus avalae Soyka (Hymenoptera: Mymari-
dae),withnewsynonymies. FrustulaEntomologica20: 119-126.
Doutt,R.L. andJ.Nakata. 1965. Parasitesforcontrolofgrapeleafhopper. CaliforniaAgriculture 19: 3-5.
Hamilton, K.G.A. 1985. Leafhoppers ofornamental andfruittrees inCanada. Publication 1779/E, Commu-
nicationsBranch,AgricultureandAgri-FoodCanada.
Huber, J.T. 1986. Systematics, biology, and hosts ofthe Mymaridae and Mymarommatidae (Insecta: Hy-
J.Entomol. Soc. Brit.Columbia 104,December2007 15
menoptera): 1758-1984.Entomography4: 185-243.
Kido, H., D.L. Flaherty, D.F. Bosch, and K.A. Valero. French pruce trees as overwintering sites for the
grapeleafhoppereggparasite. AmericanJournalofEnologyandviticulture35(3): 156-160.
McKenzie, L.M. 1973. TheGrapeLeafhopper,Erythroneuraziczac (Homoptera: Cicadellidae) andits My-
marid (Hymenoptera) Egg-Parasite in the Okanagan Valley, British Columbia. M.Sc. Thesis, Depart-
mentofBiological Science, SimonEraserUniversity, Bumaby,BritishColumbia.
Mulla, M.S. 1956. TwoMymarideggparasitesattacking Typhlocybaspecies inCalifornia. Journal ofEco-
nomicEntomology49:438-441.
Pickett, C.H., L.T. Wilson, D. Gonzalez and D.L. Flaherty. 1987. Biological control ofvariegated grape
leafhopper. CaliforniaAgriculture41: 14-16.
Triapitsyn, S.V. 1995. The identities ofAnagrus (Hymenoptera: Mymaridae) egg parasitoids ofthe grape
andblackberryleafhoppers(Homoptera: Cicadellidae)inCalifornia. PanPacificEntomologist. 71: 250-
251.
Triapitsyn, S.V. 1998. Anagrus (Hymenoptera: Mymaridae)eggparasitoids ofErythroneura spp. andother
leafhoppers(Homoptera: Cicadellidae) inNorthAmericanvineyards andorchards: ataxonomicreview.
TransactionsoftheAmericanEntomological Society 124: 77-112.
Triapitsyn, S.V. 2001. Reviewofthe Australasian species ofAnagrus (Hymenoptera: Mymaridae). Belgian
JournalofEntomology3(2): 267-289.
Triapitsyn, S.V. andA.J. Teulon. 2002. Onthe identity ofAnagrus(Hymenoptera: Mymaridae) eggparasi-
toids of Froggatt's apple leafhopper, Edwardsiana crataegi (Douglas) (Homoptera: Cicadellidae), in
Christchurch,NewZealand.NewZealandEntomologist25: 91-92.
Trjapitzin, S.V., and E. Chiappini. 1994. A new Anagrus (Hymenoptera: Mymaridae) egg parasitoid of
Erythroneuraspp. (Homoptera Cicadellidae). EntomologicalNews 105: 137-140.
:
Vidano, C, andA. Arzone. 1982. BiotaxonomyandepidemiologyofTyphlocybinae on vine, pp. 75-85. In
Knight, W.J.,N.C. Pant, T.S. Robertson andM.R. Wilson (Eds.), Proceedings ofthe First International
Workshop on Biotaxonomy, Classification and Biology of Leafhoppers and Planthoppers
(Auchenorrhyncha) ofEconomic Importance, London, 4-7 October 1982. Commonwealth Institute of
Entomology,London.
Vidano, C,A. ArzoneandA. Amo. 1987. Researchesonnaturalenemies ofviticolousAuchenorrhynca,pp
97-101.In R. Cavalloro (Ed.), Integratedpestcontrol inviticulture. Proceedingsofameetingofthe EC
Experts' Group, Portoferraio,26-28 Sept, 1985,Amsterdam.
Williams, D.W. 1983. Ecology ofa blackberry-leafhopper-parasite system and its relevance to California
grapeagroecosystems. Hilgardia52: 1-32.
Williams, L., and T.E. Martinson. 2000. Colonization of New York vineyards by Anagrus spp.
(Hymenoptera: Mymaridae): overwinteringbiology, within-vineyarddistribution ofwasps, andparasit-
ism ofgrape leafhopper, Erythroneura spp. (Homoptera: Cicadellidae), eggs. Biological Control 18:
136-146.
J.Entomol. Soc.Brit.Columbia 104,December2007