This paper documents the first occurrence of Hexacola neoscatellae, a shore fly parasitoid, in Canada. The discovery of H. neoscatellae is significant because currently there are no suitable biological control agents available for shore fly control to the floriculture industry

Allen, Wayne R

Carney, Vanessa A

Diamond, Joshua C

Murphy, Graeme D

English

ValpoScholar

The Great Lakes Entomologist 
Volume 34 
Number 2 - Fall/Winter 2001 Number 2 - Fall/
Winter 2001 
Article 5 
October 2001 
First Canadian Record of Hexacola Neoscatellae (Hymenoptera: 
Figitidae: Eucoilinae), A Parasitoid of the Shore Fly, Scatella 
Stagnalis 
Joshua C. Diamond 
Niagara Peninsula Conservation Authority 
Vanessa A. Carney 
Agriculture and Agri-Food Canada 
Graeme D. Murphy 
Ontario Ministry of Agriculture 
Wayne R. Allen 
Agriculture and Agri-Food Canada 
Follow this and additional works at: https://scholar.valpo.edu/tgle 
 Part of the Entomology Commons 
Recommended Citation 
Diamond, Joshua C.; Carney, Vanessa A.; Murphy, Graeme D.; and Allen, Wayne R. 2001. "First Canadian 
Record of Hexacola Neoscatellae (Hymenoptera: Figitidae: Eucoilinae), A Parasitoid of the Shore Fly, 
Scatella Stagnalis," The Great Lakes Entomologist, vol 34 (2) 
Available at: https://scholar.valpo.edu/tgle/vol34/iss2/5 
This Peer-Review Article is brought to you for free and open access by the Department of Biology at ValpoScholar. 
It has been accepted for inclusion in The Great Lakes Entomologist by an authorized administrator of ValpoScholar. 
For more information, please contact a ValpoScholar staff member at scholar@valpo.edu. 
2001 THE GREAT LAKES ENTOMOLOGIST 51 
FIRST CANADIAN RECORD OF HEXACOLA NEOSCATELLAE 
(HYMENOPTERA: FIGITIDAE: EUCOILlNAE), A PARASITOID 
OFTHE 
SHORE 
FLY, SCATELLA STAGNALIS 
loshua C. Diamondl Vanessa A. Carney I Graeme D. Murphy3 , and Wayne R. Allen2 I 
ABSTRACT 
This paper documents the first occurrence ofHexacola neoscatellae, a shore 
fly parasitoid, in Canada. The discovery of H. neoscatellae is significant be­
cause currently there are 
no 
suitable biological control agents available for 
shore 
fly control to 
the floriculture industry. 
Scatella stagnalis Fallen (Diptera: Ephydridae) is a worldwide cosmopoli­
tan 
species (Zack 
and Foote 1978). This species of shore fly is commonly found in
greenhouses where it breeds on algae growing on the potting mix, pots, benches 
and 
floors. Shore flies have been traditionally 
identified as a nuisance pest to 
greenhouse workers and consumers of potted crops (Vanninen and Koskula 1998). 
Recently, S. stagnalis has been implicated as a vector of plant pathogens, in­
creasing the incidence of root disease. Goldberg and Stanghellini (1990) docu­
mented the 
acquisition 
and aerial transmission of Pythium aphanidermatum 
(Edson) by shore flies from infected to healthy plants in greenhouses. Adult 
shore flies also cause indirect damage to ornamentals by leaving fecal spots on 
the 
foliage, 
thus reducing the aesthetic value of the plant (Lindquist et al. 1994). 
The 
use 
of chemicals ha been the cornerstone for insect control in greenhouses. 
However, th floriculture industry has experienced a reduction in both the num­
ber and 
classes 
of traditional pesticides available because fewer products are 
being registered and many older products are not being registered again. There 
are 
also growing 
health and environmental concerns influencing this reduction. 
The trend toward an 
increased 
use of biological controls for management ofother 
crop pests is anothe incentive to move away from the application of chemicals to 
control shore flies. As yet, there are few effective shore fly control alternatives 
available (Vanninen and Koskula 1998). 
In 
our greenhouses where shore flies exist, yellow sticky-card monitoring 
revealed a resident population of a 
Hexacola sp. Hexacola neoscatellae Beardsley 
is known to be a parasitoid ofEphydridae (Beardsley 1989). These specimens (Fig. 
1) 
from 
our greenhouses were identified as Hexacola neoscatellae Beardsley by 
Matthew 
Buffington (Texas 
A. & M. University) and John W. Beardsley (Univer­
sity of Hawaii). We report here that specimens from our greenhouse were ob­
served parasitizing shore fly larvae and pupa (Figs.2-3). Previously, H. neoscatellae 
has only been identified from greenhouses at University of California Riverside, 
and 
occurs naturally throughout Hawaii (Beardsley 1989). 
It is likely H. neoscatellae 
arrived in our greenhouses by being carried on nursery stock. 
Another 
species, 
Hexacola hexatoma (Hartig), has been report d to para­
sitize shore 
flies (Gill 
and Sanderson 1998). However, according to Gora 
Nordlander 
(pers. comm.), 
this association is likely due to a misidentification 
ofII. neoscatellae as II. hexatoma, a well-known parasitoid of frit flies (Diptera: 
INiagara Peninsula Conservation Authority, 250 Thorold Rd West, WeIland, ON 

Canada, L3C 3W2. 

2Agriculture and Agri-Food Canada, S uthern Crop Protection and F od Research 

Centre, 4902 Victoria Ave North, Vineland Station, ON Canada, LOR 2EO. 

30ntario Ministry of Agriculture, Food and Rural Affairs, 4390 Victoria Ave North, 
Vineland Station, ON Canada, LOR 2EO. 
1
Diamond et al.: First Canadian Record of Hexacola Neoscatellae (Hymenopter
Published by ValpoScholar, 2001
52 THE GREAT LAKES ENTOMOLOGIST Vol. 34, No.2 
I 1 mm • 
1 
FIG. 1. Hexacola neoscatellae: 1, Adult. 
FIGS. 2-3. Hexacola neoscatellae: 2, shore fly pupal case containing the developing 
wasp 
(white) 
and the remnants of the dead shore fly pupa (black); 3, parasite dissected 
from the shore fly pupa. 
2
The Great Lakes Entomologist, Vol. 34, No. 2 [2001], Art. 5
https://scholar.valpo.edu/tgle/vol34/iss2/5
2001 THE GREAT LAKES ENTOMOLOGIST 53 
Chloropidae). Beardsley's (1989) comparison ofH. neoscatellae to H. hexatoma 
indicates that these species differ in a number of morphological c aracteris­
tics, such as: the antennae are not pale basally and do not have a clearly de­
fined six-segmented club with rhinaria on all six segments; th back of the 
head 
is 
not discernibly striate and the basal hair ring of the gaster is not dense. 
Therefore, we find it possible thatH. neoscatellae has either been misidentified 
as H. hexatoma or these two distinct species have an overlapping h st range. 
In either 
case, 
and with regards to our findings, specimens of H. hexatoma that 
have been confirmed as a parasitoid of shore flies should be viewed as suspi­
cious and specimens should be reevaluated to determined its correct identifica­
tion to resolve this issue. 
This population of H. neoscatellae found in Vineland Station, Ontario 
(43011NN; 79° 24NW), is the first to be documented within Ca ada. This dis­
covery provides a potential new biological control agent that once introduced, 
could sustain itself and maintain S. stagnalis below nuisance levels at little or 
no cost to greenhouses operators. Optimal parameters for rearing (e.g., tem­
perature, 
light, 
relative humidity, host rearing) and the testing of the biologi­
cal control potential of this parasitoid is being determined. Voucher specimens 
of this 
species 
are now housed at Canadian National Insect Collection, ECORC­
AAFC, Ottawa. 
ACKNOWLEDGMENTS 
Research was 
funded 
through Flowers Canada (Ontario) and The Agri­
cultural Adaptation 
Council 
of Canada with matching funds from AAFC. We 
are grateful 
to 
Matthew Buffington (Texas A. & M. University) and the late 
John W. Beardsley 
(University 
of Hawaii) for specimen identifications. We 
would like to thank Goran Nordlander (Swedish University ofAgricultural Sci­
ences) and Jennifer Read (ECORC-AAFC, Ottawa) for species information. We 
would also like to thank an anonymous reviewer for reading the manuscript 
and 
providing useful suggestions. 
LITERATURE CITED 
Beardsley, J. W. 1989. Hawaiian Eucoilidae (Hymenoptera: Cynipoidea), key to 
and 
taxonomic notes on 
apparently non-endemic species. Proceedings of the 
ian 
Entomological Society 29: 165-194. 
Gill, S. 
and J. Sanderson. 1998. Ball Identification Guide t Greenhouse Pests and 
Beneficials. Ball Publishing, Illinois. 
Goldberg, N.P. and M.E. Stanghellini. 1990. Ingestion-egestion and aerial transmission 
ofPythium aphanidermatum by shore flies (Ephydrinae: Scatella stagnalis). Phyto­
pathology 80: 1244-1246. 
Lindquist, R, J.Buxton, and J. Piatkowski. 1994. Biological control of sciarid flies and 
shore flies n glasshouses. Brighton Crop Protection Conference: Pest and Disease 
1994,1067-1072. 
Vanninen, I and H. Koskula.1998. Effect of hydrogen peroxide on algal growth, cucmn­
ber 
seedlings 
and reproduction of shore flies (Scat lla stagnalis) in rock wool. Crop 
Protection 17: 547-553. 
Zack, R.S. and B.A. Foote. 1978. Utilization of algal monocultures by larvae of Scatella 
stagnalis. Environ. Entomol. 7: 509-511. 
3
Diamond et al.: First Canadian Record of Hexacola Neoscatellae (Hymenopter
Published by ValpoScholar, 2001
54 THE GREAT LAKES ENTOMOLOGIST Vol. 34,No.2 
4
The Great Lakes Entomologist, Vol. 34, No. 2 [2001], Art. 5
https://scholar.valpo.edu/tgle/vol34/iss2/5

First Canadian Record of \u3ci\u3eHexacola Neoscatellae\u3c/i\u3e (Hymenoptera: Figitidae: Eucoilinae), A Parasitoid of the Shore Fly, \u3ci\u3eScatella Stagnalis\u3c/i\u3e

Valparaiso University

The Great Lakes Entomologist Volume 34 Number 2 - Fall/Winter 2001 Number 2 - Fall/Winter 2001 Article 5 October 2001 First Canadian Record of Hexacola Neoscatellae (Hymenoptera: Figitidae: Eucoilinae), A Parasitoid of the Shore Fly, Scatella Stagnalis Joshua C. Diamond Niagara Peninsula Conservation Authority Vanessa A. Carney Agriculture and Agri-Food Canada Graeme D. Murphy Ontario Ministry of Agriculture Wayne R. Allen Agriculture and Agri-Food Canada Follow this and additional works at: https://scholar.valpo.edu/tgle Part of the Entomology Commons Recommended Citation Diamond, Joshua C.; Carney, Vanessa A.; Murphy, Graeme D.; and Allen, Wayne R. 2001. "First Canadian Record of Hexacola Neoscatellae (Hymenoptera: Figitidae: Eucoilinae), A Parasitoid of the Shore Fly, Scatella Stagnalis," The Great Lakes Entomologist, vol 34 (2) Available at: https://scholar.valpo.edu/tgle/vol34/iss2/5 This Peer-Review Article is brought to you for free and open access by the Department of Biology at ValpoScholar. It has been accepted for inclusion in The Great Lakes Entomologist by an authorized administrator of ValpoScholar. For more information, please contact a ValpoScholar staff member at scholar@valpo.edu. 2001 THE GREAT LAKES ENTOMOLOGIST 51 FIRST CANADIAN RECORD OF HEXACOLA NEOSCATELLAE (HYMENOPTERA: FIGITIDAE: EUCOILlNAE), A PARASITOID OFTHE SHORE FLY, SCATELLA STAGNALIS loshua C. Diamondl Vanessa A. Carney I Graeme D. Murphy3 , and Wayne R. Allen2 I ABSTRACT This paper documents the first occurrence ofHexacola neoscatellae, a shore fly parasitoid, in Canada. The discovery of H. neoscatellae is significant be­cause currently there are no suitable biological control agents available for shore fly control to the floriculture industry. Scatella stagnalis Fallen (Diptera: Ephydridae) is a worldwide cosmopoli­tan species (Zack and Foote 1978). This species of shore fly is commonly found ingreenhouses where it breeds on algae growing on the potting mix, pots, benches and floors. Shore flies have been traditionally identified as a nuisance pest to greenhouse workers and consumers of potted crops (Vanninen and Koskula 1998). Recently, S. stagnalis has been implicated as a vector of plant pathogens, in­creasing the incidence of root disease. Goldberg and Stanghellini (1990) docu­mented the acquisition and aerial transmission of Pythium aphanidermatum (Edson) by shore flies from infected to healthy plants in greenhouses. Adult shore flies also cause indirect damage to ornamentals by leaving fecal spots on the foliage, thus reducing the aesthetic value of the plant (Lindquist et al. 1994). The use of chemicals ha been the cornerstone for insect control in greenhouses. However, th floriculture industry has experienced a reduction in both the num­ber and classes of traditional pesticides available because fewer products are being registered and many older products are not being registered again. There are also growing health and environmental concerns influencing this reduction. The trend toward an increased use of biological controls for management ofother crop pests is anothe incentive to move away from the application of chemicals to control shore flies. As yet, there are few effective shore fly control alternatives available (Vanninen and Koskula 1998). In our greenhouses where shore flies exist, yellow sticky-card monitoring revealed a resident population of a Hexacola sp. Hexacola neoscatellae Beardsley is known to be a parasitoid ofEphydridae (Beardsley 1989). These specimens (Fig. 1) from our greenhouses were identified as Hexacola neoscatellae Beardsley by Matthew Buffington (Texas A. & M. University) and John W. Beardsley (Univer­sity of Hawaii). We report here that specimens from our greenhouse were ob­served parasitizing shore fly larvae and pupa (Figs.2-3). Previously, H. neoscatellae has only been identified from greenhouses at University of California Riverside, and occurs naturally throughout Hawaii (Beardsley 1989). It is likely H. neoscatellae arrived in our greenhouses by being carried on nursery stock. Another species, Hexacola hexatoma (Hartig), has been report d to para­sitize shore flies (Gill and Sanderson 1998). However, according to Gora Nordlander (pers. comm.), this association is likely due to a misidentification ofII. neoscatellae as II. hexatoma, a well-known parasitoid of frit flies (Diptera: INiagara Peninsula Conservation Authority, 250 Thorold Rd West, WeIland, ON Canada, L3C 3W2. 2Agriculture and Agri-Food Canada, S uthern Crop Protection and F od Research Centre, 4902 Victoria Ave North, Vineland Station, ON Canada, LOR 2EO. 30ntario Ministry of Agriculture, Food and Rural Affairs, 4390 Victoria Ave North, Vineland Station, ON Canada, LOR 2EO. 1Diamond et al.: First Canadian Record of Hexacola Neoscatellae (HymenopterPublished by ValpoScholar, 200152 THE GREAT LAKES ENTOMOLOGIST Vol. 34, No.2 I 1 mm • 1 FIG. 1. Hexacola neoscatellae: 1, Adult. FIGS. 2-3. Hexacola neoscatellae: 2, shore fly pupal case containing the developing wasp (white) and the remnants of the dead shore fly pupa (black); 3, parasite dissected from the shore fly pupa. 2The Great Lakes Entomologist, Vol. 34, No. 2 [2001], Art. 5https://scholar.valpo.edu/tgle/vol34/iss2/52001 THE GREAT LAKES ENTOMOLOGIST 53 Chloropidae). Beardsley's (1989) comparison ofH. neoscatellae to H. hexatoma indicates that these species differ in a number of morphological c aracteris­tics, such as: the antennae are not pale basally and do not have a clearly de­fined six-segmented club with rhinaria on all six segments; th back of the head is not discernibly striate and the basal hair ring of the gaster is not dense. Therefore, we find it possible thatH. neoscatellae has either been misidentified as H. hexatoma or these two distinct species have an overlapping h st range. In either case, and with regards to our findings, specimens of H. hexatoma that have been confirmed as a parasitoid of shore flies should be viewed as suspi­cious and specimens should be reevaluated to determined its correct identifica­tion to resolve this issue. This population of H. neoscatellae found in Vineland Station, Ontario (43011NN; 79° 24NW), is the first to be documented within Ca ada. This dis­covery provides a potential new biological control agent that once introduced, could sustain itself and maintain S. stagnalis below nuisance levels at little or no cost to greenhouses operators. Optimal parameters for rearing (e.g., tem­perature, light, relative humidity, host rearing) and the testing of the biologi­cal control potential of this parasitoid is being determined. Voucher specimens of this species are now housed at Canadian National Insect Collection, ECORC­AAFC, Ottawa. ACKNOWLEDGMENTS Research was funded through Flowers Canada (Ontario) and The Agri­cultural Adaptation Council of Canada with matching funds from AAFC. We are grateful to Matthew Buffington (Texas A. & M. University) and the late John W. Beardsley (University of Hawaii) for specimen identifications. We would like to thank Goran Nordlander (Swedish University ofAgricultural Sci­ences) and Jennifer Read (ECORC-AAFC, Ottawa) for species information. We would also like to thank an anonymous reviewer for reading the manuscript and providing useful suggestions. LITERATURE CITED Beardsley, J. W. 1989. Hawaiian Eucoilidae (Hymenoptera: Cynipoidea), key to and taxonomic notes on apparently non-endemic species. Proceedings of the ian Entomological Society 29: 165-194. Gill, S. and J. Sanderson. 1998. Ball Identification Guide t Greenhouse Pests and Beneficials. Ball Publishing, Illinois. Goldberg, N.P. and M.E. Stanghellini. 1990. Ingestion-egestion and aerial transmission ofPythium aphanidermatum by shore flies (Ephydrinae: Scatella stagnalis). Phyto­pathology 80: 1244-1246. Lindquist, R, J.Buxton, and J. Piatkowski. 1994. Biological control of sciarid flies and shore flies n glasshouses. Brighton Crop Protection Conference: Pest and Disease 1994,1067-1072. Vanninen, I and H. Koskula.1998. Effect of hydrogen peroxide on algal growth, cucmn­ber seedlings and reproduction of shore flies (Scat lla stagnalis) in rock wool. Crop Protection 17: 547-553. Zack, R.S. and B.A. Foote. 1978. Utilization of algal monocultures by larvae of Scatella stagnalis. Environ. Entomol. 7: 509-511. 3Diamond et al.: First Canadian Record of Hexacola Neoscatellae (HymenopterPublished by ValpoScholar, 200154 THE GREAT LAKES ENTOMOLOGIST Vol. 34,No.2 4The Great Lakes Entomologist, Vol. 34, No. 2 [2001], Art. 5https://scholar.valpo.edu/tgle/vol34/iss2/5

First Canadian Record of \u3ci\u3eHexacola Neoscatellae\u3c/i\u3e (Hymenoptera: Figitidae: Eucoilinae), A Parasitoid of the Shore Fly, \u3ci\u3eScatella Stagnalis\u3c/i\u3e

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