A distribution and establishment program for Chilocorus kuwanae (Silvestri) (Coleoptera: Coccinellidae) in the United States

4 Pages·1991·1.9 MB·

by  R M Hendrickson

PROC. ENTOMOL. SOC. WASH.
93(1), 1991, pp. 197-200
A DISTRIBUTION AND ESTABLISHMENT PROGRAM FOR
CHILOCORUS KUWANAE (SILVESTRI)
(COLEOPTERA: COCCINELLIDAE) IN THE UNITED STATES
R. M. Hendrickson, Jr., J. J. Drea, and Mike Rose
(RMH) Beneficial Insects Research Laboratory, Agricultural Research Service, U.S.
Department of Agriculture, 501 South Chapel Street, Newark, Delaware 19713; (JJD)
Beneficial Insects Laboratory, BBII, Agricultural Research Service, U.S. Department of
Agriculture, BARC-East, Beltsville, Maryland 20705; (MR) Entomology/Biological Con-
A&M
trol, Texas University, College Station, Texas 77843.
Abstract.—Chilocorus kuwanae, a coccinellid predator ofeuonymus scale, Unaspis eu-
onymi (Comstock) (Homoptera: Diaspididae), was introduced from Korea (1984) and
Japan (1985) into the United States. The beetle was released in 25 states in the eastern
halfofthe country and became established in nine states (CN, DE, MA, MD, MI, NC,
NJ, OH, PA) and the District ofColumbia.
Key Words: Insecta, Coccinellidae, Chilocorus kuwanae, euonymus scale, Unaspis eu-
onymi, biological control, predator,Aprostocetus neglectus, Euonymusplants
Euonymusscale, Unaspiseuonymi(Com- USDA, initiated a Small Farms Research
stock) (Homoptera: Diaspididae), is a seri- Project in the early 1980's for control of
ouspestofmanyspeciesofornamentaltrees scale pests, one of which was euonymus
and shrubs in the United States (Gill et al. scale. Since U. euonymi is believed to be
ARS
1982). In the absence ofadequate controls, Oriental in origin, theassistance ofthe
this insect can attain populations severe Asian Parasite Laboratory, Seoul, Republic
enough to cause complete defoliation and of Korea (ROK) was requested to obtain
death ofthe host plant (Johnson and Lyon natural enemies attacking the scale in Ko-
1988). Even moderate infestations impair rea. Several species of parasites and pred-
photosynthesis and reduce growth (Cock- ators of U. euonymi were collected by the
field and Potter 1987). The pest is a nui- laboratory personnel, including the cocci-
sance to homeowners because insect-dam- nellid Chilocorus kuwanae(Silvestri). Spec-
aged shrubs are unsightly and require imensofthisbeetlewereshippedtotheARS
pesticide treatments or removal. Some at- quarantinefacilitiesatthe Beneficial Insects
Research Laboratory, Newark, Delaware.
tractive but scale-susceptible species or va-
After clearance from quarantine, the beetle
rieties ofEuonymus, an ornamental shrub was sent to the ARS Beneficial Insects Lab-
or tree, are no longer produced by nursery-
oratory, Beltsville, Maryland, foradditional
men sincetheplantsrequire frequentchem-
studies, culture, andrelease(Dreaand Carl-
ical pest control (Drea and Hendrickson
1988). A biological control method for eu- son 1987).
onymusscalecouldreopenmarketsforthese Methods and Materials
Euonymus. From 1984to 198641 1 adultC. kuwanae
TheAgriculturalResearchService(ARS), werereceived from thelaboratoryin Korea.
198 PROCEEDINGSOFTHE ENTOMOLOGICALSOCIETYOFWASHINGTON
Initially these specimens were used to es- All cooperators replied to the question-
tablish laboratory cultures. F, adults, lar- naire. From their replies and personal field
vae, and a small number ofeggs from these observations we determined that C. kuwa-
cultures were released at the U.S. National nae was established in CN, DC, DE, MA,
Arboretum, Washington, D.C., on Euony- MD, MI, NC, NJ, OH, and PA for one or
mus europaeus L. in 1984. Color photo- more years (Fig. 1). In some areas, insuffi-
graphsofthepredatorscanbefoundinHen- cient time had elapsed since release to de-
drickson and Drea (1988). termine winter survival.
The predator became established at the Releases made in Texas failed to estab-
Arboretum. By 1985 this primary release hsh. One ofus (MR) obtained 231 1 adult,
C
site had become a natural insectary and larval and pupal stages of kuwanaefrom
servedas the main source ofliving material Maryland and Delaware sites in 21 con-
for laboratory cultures and for subsequent signments from August 1987 to September
distribution of the predator to secondary 1989. These were released on euonymus
release sites in MD, DE, PA, NJ and DC. scale at numerous sites in Austin, Bryan,
Populations ofbeetles at these locations CollegeStation,andDallas/Ft.Worth.Only
increased rapidly. For example, in Swarth- a few cast larval skins were found and by
m
more, PA, a single shrub, ca. 2.5 diam., July 1990 only one adult was recovered.
C
provided 7135 beetles in the year following Release sites in Texas were ant-free and
the initial release of84 C. kuwanae adults kuwanaeadultsreadilyfedontheabundant
on the shrub. During the period 1985 to scale insects. Chilocorus kuwanae adults
1989atotalof16,157 beetleswerecollected were observed to feed and remain alive for
andredistributedfromtheprimaryandsec- 10 days in branch sleeve cages following
ondary sites. Ultimately, beetles were re- colonization. Failure to establish may be
leased directly or sent to cooperators in 24 related to climatic conditions, especially
states (AL, AR, CN, DE, FL, GA, KS, KY, heat. Surveys are now being conducted to
MA, MD, MI, MO, NC,NH,NY, OH, OK, determine overwinter survivalship and re-
PA, VA, RI, TN, TX, VT, WV) and DC. production ofadult C. kuwanaereleased in
C
In 1986, ninespecimensof kuwanae, col- October, 1989. The release date was select-
lected by one of us (MR) in Japan, were ed to initially circumvent high summer
culturedatBeltsvilleand53specimenswere temperaturesandto studythepotentialcol-
supplied to the New Jersey Department of onizations of the beetle at lower tempera-
Agriculture, Trenton. ture.
To determine the success of the project Anexample suggestingtheimportanceof
by 1989, questionnaires requesting infor- heat in preventing establishment of this
mation relating to the outcome ofreleases predatoroccurred in Delaware. Five releas-
madeatvariouslocationsthroughoutmuch es of C. kuwanae totalling 60 individuals
oftheeastern United States, were mailedto were made in 1986 and 1987 on 22 small
cooperators in June and reported in this specimens (less than 30 cm high) ofa pros-
study. trate, variegated variety ofEuonymusfor-
tunei, infested with euonymus scale, grow-
Results and Discussion
ing on the grounds ofthe Beneficial Insects
By 1987, the scale populations had been Research Laboratory, Newark, DE. The
reduced to a very low level at the Arbore- beetles never remained on the plants more
tum, the primary release site (Drea and than 2 or 3 days and failed to establish.
Carlson 1987). By 1989 the scale insects These plants were individually isolatedand
were almost absent from the trees and the surrounded by bare soil. Heat rising from
coccinellid was difficult to find. the exposed soil on sunny days may have
VOLUME 93, NUMBER 1 199
Fig. 1. Distribution ofChilocoruskuwanaein eastern UnitedStates. A solid circle indicatesestablishment,
an open circle representsone or more releases without confirmedestablishment in that state.
repelled the predators. In contrast, beetles noma sessile (Say) (Hymenoptera: Formic-
becameestablishedonanextensiveground- idae).
cover planting of the same species at Larvae of C. kuwanae, collected from
Swarthmore, PA, that had no bare soil to study sites in Delaware and Maryland dur-
reflect heat. ing 1988 and 1989, were parasitized by
Thepresenceofantsmaybeanothercon- Aprostocetus neglectus (Domenichini) (Hy-
sideration when selecting release sites for menoptera: Eulophidae: Tetrastichinae).
the coccinellid. At some locations in DE, The identifier, John LaSalle, noted that this
MD, and PA, the beetles failed to establish, species is known from Europe, the Middle
or ifestablished, failed to develop popula- East and North Africa where it is a parasite
tions high enough to control the scale over ofcoccinellid larvae and pupae. The para-
a several year period. These shrubs or trees site was previously unknown from North
were always ant infested. There were nu- America.
merous ants tending honeydew producers Noparasiteshavebeen rearedfrom adults
such as aphids and planthoppers. The ants of C. kuwanae originating from field sites
repeatedly stunglarvae and pupae ofC. ku- in the U.S. To eliminate the possibility of
wanaeand removed stung individualsfrom further distributingA. neglectus, only adult
theshrubs. Antspeciesonshrubswereiden- C. kuwanae are utilized for new field colo-
tified as Camponotus nearcticus Emery, C. nizations.
ferrugineus (F.), Formica pallidefuha La- Our best estimate of the rate of move-
C
treille, Lasius alienus (Foerster) and Tapi- ment by kuwanae was determined from
200 PROCEEDINGS OFTHE ENTOMOLOGICAL SOCIETY OFWASHINGTON
adultsreared from pupaecollected by R. D. vided by R. D. Gordon (Coccinellidae), D.
MD
Gordon in Bowie, in August, 1989. R. Smith (Formicidae),bothSystematicEn-
Specimens probably dispersed from our tomology Laboratory, Agricultural Re-
closest colonization sites at either Beltsville search Service, USDA, Washington, DC,
Agricultural Research Center, Maryland, a and J. LaSalle (Eulophidae), C.A.B. Insti-
distance of ca. 1 1 km in 5 years, or from tute ofEntomology, London, United King-
the U.S. National Arboretum, Washington, dom. The manuscript was reviewed by R.
DC, a distance ofca. 19 km in 6 years. It D. Gordon, and D. E. Meyerdirk, Animal
appears that the rate ofmovement is about andPlant Health Inspection Service, USDA,
2-3 km per year. Hyattsville, MD.
The use ofcooperators for disseminating
Literature Cited
thebeetlehasgreatlyenhancedtheslowrate
ofnaturaldispersal. Asaresultofthiseffort, Cockfield,S. D.andD.A. Potter. 1987. Distribution
C. kuwanaehas become established in nine development, and feeding impact of euonymus
states and the District ofColumbia during scales (Homoptera: Diaspididae) on Euonymus
the six year period from 1984 to 1989. We fortunei under greenhouse conditions. Environ-
mental Entomology 16: 917-921.
are hopeful that additional cooperator as- Drea, J. J. and R. W. Carison. 1987. The establish-
sistance and future involvement ofthe An- ment ofChilocorus kuwanae (Coleoptera: Cocci-
imal and Plant Health Inspection Service, nellidae) in eastern United States. Proceedings of
USDA, will resultinthecollectionandwide theEntomologicalSocietyofWashington89:821-
824.
dissemination of the predator throughout
Drea, J. J. and R. M. Hendrickson, Jr. 1988. Exotic
the U.S.
predators. American Nurseryman 168(8): 66-71.
Acknowledgments Gill, S. A., D. R. Miller, and J. A. Davidson. 1982.
Bionomicsand taxonomy oftheeuonymusscale,
We thank Ho-Yeon Han and Jang-Hoon Unaspis euonymi (Comstock), and detailed bio-
Lee, Asian Parasite Laboratory, USDA, logicalinformationonthescaleinMaryland.Uni-
ARS, Seoul, Republic of Korea who sup- versityofMaryland Agricultural ExperimentSta-
tion Miscellaneous Publications Number 969. 36
plied the original material; and S. E. Earth, pp.
Beneficial Insects Research Laboratory, Ag- Hendrickson, R. M., Jr. and J. J. Drea. 1988. Our
ricultural Research Service, USDA, New- insect allies: Beetles battle scale. Explorer 30(4):
ark, DEand E. McClunin, Beneficial Insects 4-8.
Laboratory, ARS, USDA, Beltsville, MD, Johnson, W. T. and H. H. Lyon. 1988. Euonymus
scales, pp. 388-389. In Insectsthat FeedonTrees
whoassisted in collecting, culturing, and re- andShrubs. 2nded.CornellUniversityPress,Ith-
leasingChilocorus. Identificationswerepro- aca, NY.