Cryostored eggs of Colorado potato beetle, Leptinotarsa decemlineata (Say) eggs were suitable hosts for Edovum puttleri. Parasitism rates were low, however this study was first to show that rearing the parasite on eggs stored at ultra low temperatures (-70 0 C) is feasible. This method of storage will facilitate mass production of E. puttleri as well as prevent loss of the parasite in the event of a crash in the Colorado potato beetle colony

Schroder, R. F. W

English

ValpoScholar

The Great Lakes Entomologist 
Volume 30 
Number 4 - Winter 1997 Number 4 - Winter 
1997 
Article 5 
December 1997 
Feasibility of Using Cryostored Colorado Potato Beetle 
(Coleoptera: Chrysomelidae) Eggs for Rearing Edovum Puttleri 
(Hymenoptera: Eulophidae) 
R. F. W. Schroder 
USDA 
Follow this and additional works at: https://scholar.valpo.edu/tgle 
 Part of the Entomology Commons 
Recommended Citation 
Schroder, R. F. W. 1997. "Feasibility of Using Cryostored Colorado Potato Beetle (Coleoptera: 
Chrysomelidae) Eggs for Rearing Edovum Puttleri (Hymenoptera: Eulophidae)," The Great Lakes 
Entomologist, vol 30 (3) 
Available at: https://scholar.valpo.edu/tgle/vol30/iss3/5 
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. 
THE GREAT LAKES ENTOMOLOGIST1997 177 
FEASIBILITY OF USING CRYOSTORED COLORADO POTATO BEETLE 
(COLEOPTERA: CHRYSOMELIDAEl EGGS FOR REARING EDOVUM 
PUTTLERI (HYMENOPTERA: EULOPHIDAEl 
R.F.W. Schroderl 
ABSTRACT 
Cryostored 
eggs 
of Colorado potato beetle, Leptinotarsa decemlineata 
(Say) eggs were suitable hosts for Edovum puttleri. Parasitism rates were 
low, however this study was first to show that rea ing the parasite on eggs 
stored at ultra 
low 
temperatures (_700 C) is feasible. This method of storage 
will facilitate mass production of E. puttleri as well as prevent loss of the 
parasite in the event of
a 
crash in the Colorado potat  beetle colony. 
The potential of Edovum puttleri (EP) as a biocontrol agent of the Col­
orado potato beetle (CPB) and its utilization in IPM programs on potatoes 
and eggplant were demonstrated by Schroder and Athanas 
(1989) 
and 
Lashomb et at (1987), respectively. The limiting factors for implementing EP 
release program 
on a 
broad scale are the inability to provide adequate num­
bers on demand, the expense of mass production of 
CPB eggs. 
There are 
presently 
no effective artificial 
diets for rearing the CPB, and the costs of 
providing healthy potato foliage is expensive. If a method could be developed 
to store and recall host eggs on dema d, egg production facilities could be 
continuously and 
efficiently 
operated at specific levels. A stockpile of eggs 
could be reated and used to mass produce EP on demand. The quantities 
produced 
could 
far exceed seasonal production capabilities. Therefore, th  
cost of production may be significantly reduced as w llas make the entire 
biocontrol program cost effective. 
Cryogenic storage is a possible mean  of stockpiling CPB eggs. For the 
purpose of this 
study, cryostorage is 
the storage of Colorado potato beetle 
eggs at ultra low temperatures. Morrison (pers. comm.) showed the cryostor­
age of Sitotroga cerealella (Olivier) eggs were acceptable hosts for Tri­
chogramma pretiosum Riley parasites. Fedde et aI. (1979) chilled host eggs to 
keep them in 
a susceptable 
state for the egg parasite Telenomus alsophilae 
Vierck. Drooz and Solomon (1980) reared the encyrtid egg parasite Ooencyr­
tus ennomophagus Yoshimoto on eggs of Clostera inclusa (Hubner) kept 
below freezing. Lopez et al. (1987)showed that previously frozen S. cerea ella 
eggs are suitable hosts for rearing the predator Geocons punctipes. Maini 
and 
Nicoli (1990) observed 
that it was possible for EP to parasitize and de­
velop in CPB eggs stored at 18° C for 1-7 days. The purpose of our study was 
to 
show 
the feasibility of using cryostored Colorado potato beetle eggs as a 
host 
for 
rearing EP. 
1 USDA, ARS, Insect Biocontrol Laboratory, Plant Sciences Institute, Bldg 306, Rm 
305, BARe-East, Beltsville, MD 20705. 
1
Schroder: Feasibility of Using Cryostored Colorado Potato Beetle (Coleopter
Published by ValpoScholar, 1997
178 THE GREAT lAKES ENTOMOLOGIST Vol. 30, No.4 
MATERIALS AND METHODS 
Colorado potato beetle eggs used in these studies were obtained from the 
colony maintained in the laboratory. Eggs used in the individual tests ranged 
in 
age from 
24 to 96 h old. Eggs at a given age were collected an  the remain­
ing 
foliage 
attached to the egg mass was trimmed to the edge of the mass. 
Three to 
four egg 
masses were then glued with Elmer's® glue on a filter 
paper tab 
or 
strip. 'I\vo tabs were placed back to back and suspended (by th  
configuration of the vial) in the center of 1.8 m1 NUNC star foot cryotube 
vials which were placed in NUNC cryostore canes and preconditioned in a re­
frigerator at 5° C or placed directly in liquid nitrogen (_70" C). After precon­
ditioning, he eggs were placed in a liquid nitrogen cylinder. Following a des­
ignated time in 
liquid nitrogen 
the vials were removed and allowed to reach 
room temperature (20° C). The egg mass tabs/strips were then removed from 
the 
vials 
and placed on filter pap in a petri dish nd exposed to EP. A con­
trol was set up for each test using 0-24 h or 24-72 h old eggs and exposing 
them in 
a 
parasite stinging jar for 24 h. The lids of petri dishes containing 
the 
cyrostored eggs 
were removed and placed in a 1 gal clear glass wide­
mouth jar 
containing approximately 50 
EP (1m: 1f). The open end of the jar 
was closed with a cotton sleeve to prevent escape of the parasites. The eggs 
were exposed to the parasit s for a prescribed time in a growth chamber set 
at 
20° C., 60 % RH 
and 16L : 8D photoperiod. The dis es containing the con­
trol and cryogenic eggs were removed and held in the same growth chamber 
for hatching of CPB larvae and emergence of parasites. The numb r of eggs 
in 
each 
test varied according to the availability of eggs harvest d from the 
laboratory colony. The mean % parasitism, % hatch ofCPB larvae and % par­
asitism in the 
control 
were determined for these data. 
RESULTS AND DISCUSSION 
Tests 1 to 9 include a wide range of: preconditioning times from 0 to 144 
hours; cryostorage from 11 to 26 days; parasite ages from 3 t  42 days; para­
site 
exposure times from 
20-120 hours and number eggs exposed (Table 1). 
The resulting percent parasitism expressed in the various tests ranged from 
5.8 to 17.8%. In one of the cryovials in Test 9, 30.0% of the eggs exposed to EP 
were parasitized. Although low parasitism rates were obtained compared to 
the parasitism rate in the 
controls we were encouraged by 
the results, since 
prior 
to 
thes  studies no Colorado potato beetle eggs were reportedly placed in 
cryostorage for use in rearing E. puttleri or any other parasites or predators. 
This was 
a 
study to determine the feasibility of using cry stored eggs for 
rearing E. puttleri, therefore no detailed biological studies were conducted to 
determine 
sex ratios 
and fecundity of the parasites produced from cryostored 
eggs. However this study is the first to show that cryostorage/storage a  very 
low temperatures of Colorado potato beetle eggs for use in r aring the para­
site 
is feasible. 
Much 
additional work is required to fully understand the optimal precon­
ditioning temperature/time, 
cryostoragel conventional freezer 
storage time 
and what 
effect 
all these variables have on the sex ratio and fecundity of the 
emerging adult parasites. 
ACKNOWLEDGMENTS Thanks 
to 
Ann M. Sidor for her technical support during the course of 
this research. 
2
The Great Lakes Entomologist, Vol. 30, No. 3 [1997], Art. 5
https://scholar.valpo.edu/tgle/vol30/iss3/5
-0 
-0 
"J 
Table 1. Differences in % parasitism of cryostored Colorado potato beetle eggs by Edovllm puttleri. 
Parasitoid % Parnsitism 
Test # 
Treated 
eggs2 
Conditioning 
to,e (hrs)b 
Cryo time 
(days) 
Parasitoid 
age 
(days) 
exposure 
(hrs) Untreated eggs" 
of 
untreated 
eggs 
% Control 
parasitism -l::r: 
1 225 0 15 
4-12 72 197 5.8 53.0 
m 
Q 
"'"2 358 4 12 6-19 46 71 6.1 69.0 m ~ 
3 691 8 11 4-7 65 22 7.2 72.1 s;: 
4 176 144 19 16-40 20 138 7.4 75.4 
?';; 
m 
<n 
5 649 24 26 23 21 94 8.3 30.0 m Z 
6 
7 
8 
501 
637 
162 
24 
24 
96 
12 
11 
21 
6-19 
3 
18-42 
46 
24 
96 
61 
26 
19 
9.0 
9.4 
10.5 
54.0 
53.3 
73.0 
-l 
0 
3: 
0 5 Q 
9 321 24 1  11 120 197 17.8 53.0 
Vi 
-l 
'Note: All Colorado potato beetle were 
0-24 hrs old at beginning of test, except tests 3, 6, & 8 which were 24-72 hrs old. "Treated 
"" 
cryostored eggs. bConditioning 
"" # of hours eggs were held at 5°C. "Untreated eggs not expos d to ultra low temperatures. 
"J 
-0 
3
Schroder: Feasibility of Using Cryostored Colorado Potato Beetle (Coleopter
Published by ValpoScholar, 1997
180 THE GREAT LAKES ENTOMOLOGIST Vol. 30, No.4 
LITERATURE CITED 
Drooz, A. T. and J. D. Solomon. 1980. Rearing the egg parasite Ooencyrtus ennomopha­
gus (Hymenoptera: Encyrtidae) on eggs of Clostera inclusa (Lepidoptera: Notodonti­
dae) kept below freezing. Canadian Entomol. 107: 739-740. 
Fedde, G. F., V. H. Fedde, and A. T. Drooz. 1979. Biological control prospects of an egg 
parasite, Telenomus alsophilae Y.iereck. Pp. 123-127. In: Current Topics in Forest 
Entomology. Selected papers from the XV Int'l Congo of Ent. USDA, Forest Service, 
Gen. Tech. Rep. WO-8. 174 pp. 
Lashomb, J. H., Y. S. NgR. K. Jansson, and R. Bullock. 1987. Edovum puttleri Gris­
sell (Hymenoptera: Eulophidae), an egg parasitoid of Colorado potato beetle 
(Coleoptera: Chrysomelidae): development nd parasitism on eggplant. J. Econ. En­
tomol. 80: 65-68. 
Lopez, J. D., V. S. House, and R. K. Morrison. 1987. Suitability of frozen Sitotroga ce­
realella (Olivie ) eggs of temporary rearing of Geooris punctipes. Southwest. Ento­
mol. 12: 223-228. 
Maini, S. and G. Nicoli. 1990. Edovum puttleri (Hym.: Eulophidae): Biological activity 
and response 
to 
normal and frozen eggs of Leptinotarsa decemlineata (Col.: 
Chrysomelidae). Entomophaga 35: 185-193. 
Schroder, R. F. W. and M. M. Athanas. 1989. Use of the egg parasite Edovum puttleri 
Grissell (Hymenoptera: Eulophidae) in an IPM system developed for Colorado potato 
beetle (Coleoptera: Chrysomelidae) control on potatoes, Beltsville, Maryland. Ento­
mophaga 34: 193-199. 
4
The Great Lakes Entomologist, Vol. 30, No. 3 [1997], Art. 5
https://scholar.valpo.edu/tgle/vol30/iss3/5


Feasibility of Using Cryostored Colorado Potato Beetle (Coleoptera: Chrysomelidae) Eggs for Rearing \u3ci\u3eEdovum Puttleri\u3c/i\u3e (Hymenoptera: Eulophidae)

Valparaiso University

The Great Lakes Entomologist Volume 30 Number 4 - Winter 1997 Number 4 - Winter 1997 Article 5 December 1997 Feasibility of Using Cryostored Colorado Potato Beetle (Coleoptera: Chrysomelidae) Eggs for Rearing Edovum Puttleri (Hymenoptera: Eulophidae) R. F. W. Schroder USDA Follow this and additional works at: https://scholar.valpo.edu/tgle  Part of the Entomology Commons Recommended Citation Schroder, R. F. W. 1997. "Feasibility of Using Cryostored Colorado Potato Beetle (Coleoptera: Chrysomelidae) Eggs for Rearing Edovum Puttleri (Hymenoptera: Eulophidae)," The Great Lakes Entomologist, vol 30 (3) Available at: https://scholar.valpo.edu/tgle/vol30/iss3/5 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. THE GREAT LAKES ENTOMOLOGIST1997 177 FEASIBILITY OF USING CRYOSTORED COLORADO POTATO BEETLE (COLEOPTERA: CHRYSOMELIDAEl EGGS FOR REARING EDOVUM PUTTLERI (HYMENOPTERA: EULOPHIDAEl R.F.W. Schroderl ABSTRACT Cryostored eggs of Colorado potato beetle, Leptinotarsa decemlineata (Say) eggs were suitable hosts for Edovum puttleri. Parasitism rates were low, however this study was first to show that rea ing the parasite on eggs stored at ultra low temperatures (_700 C) is feasible. This method of storage will facilitate mass production of E. puttleri as well as prevent loss of the parasite in the event ofa crash in the Colorado potat  beetle colony. The potential of Edovum puttleri (EP) as a biocontrol agent of the Col­orado potato beetle (CPB) and its utilization in IPM programs on potatoes and eggplant were demonstrated by Schroder and Athanas (1989) and Lashomb et at (1987), respectively. The limiting factors for implementing EP release program on a broad scale are the inability to provide adequate num­bers on demand, the expense of mass production of CPB eggs. There are presently no effective artificial diets for rearing the CPB, and the costs of providing healthy potato foliage is expensive. If a method could be developed to store and recall host eggs on dema d, egg production facilities could be continuously and efficiently operated at specific levels. A stockpile of eggs could be reated and used to mass produce EP on demand. The quantities produced could far exceed seasonal production capabilities. Therefore, th  cost of production may be significantly reduced as w llas make the entire biocontrol program cost effective. Cryogenic storage is a possible mean  of stockpiling CPB eggs. For the purpose of this study, cryostorage is the storage of Colorado potato beetle eggs at ultra low temperatures. Morrison (pers. comm.) showed the cryostor­age of Sitotroga cerealella (Olivier) eggs were acceptable hosts for Tri­chogramma pretiosum Riley parasites. Fedde et aI. (1979) chilled host eggs to keep them in a susceptable state for the egg parasite Telenomus alsophilae Vierck. Drooz and Solomon (1980) reared the encyrtid egg parasite Ooencyr­tus ennomophagus Yoshimoto on eggs of Clostera inclusa (Hubner) kept below freezing. Lopez et al. (1987)showed that previously frozen S. cerea ella eggs are suitable hosts for rearing the predator Geocons punctipes. Maini and Nicoli (1990) observed that it was possible for EP to parasitize and de­velop in CPB eggs stored at 18° C for 1-7 days. The purpose of our study was to show the feasibility of using cryostored Colorado potato beetle eggs as a host for rearing EP. 1 USDA, ARS, Insect Biocontrol Laboratory, Plant Sciences Institute, Bldg 306, Rm 305, BARe-East, Beltsville, MD 20705. 1Schroder: Feasibility of Using Cryostored Colorado Potato Beetle (ColeopterPublished by ValpoScholar, 1997178 THE GREAT lAKES ENTOMOLOGIST Vol. 30, No.4 MATERIALS AND METHODS Colorado potato beetle eggs used in these studies were obtained from the colony maintained in the laboratory. Eggs used in the individual tests ranged in age from 24 to 96 h old. Eggs at a given age were collected an  the remain­ing foliage attached to the egg mass was trimmed to the edge of the mass. Three to four egg masses were then glued with Elmer's® glue on a filter paper tab or strip. 'I\vo tabs were placed back to back and suspended (by th  configuration of the vial) in the center of 1.8 m1 NUNC star foot cryotube vials which were placed in NUNC cryostore canes and preconditioned in a re­frigerator at 5° C or placed directly in liquid nitrogen (_70" C). After precon­ditioning, he eggs were placed in a liquid nitrogen cylinder. Following a des­ignated time in liquid nitrogen the vials were removed and allowed to reach room temperature (20° C). The egg mass tabs/strips were then removed from the vials and placed on filter pap in a petri dish nd exposed to EP. A con­trol was set up for each test using 0-24 h or 24-72 h old eggs and exposing them in a parasite stinging jar for 24 h. The lids of petri dishes containing the cyrostored eggs were removed and placed in a 1 gal clear glass wide­mouth jar containing approximately 50 EP (1m: 1f). The open end of the jar was closed with a cotton sleeve to prevent escape of the parasites. The eggs were exposed to the parasit s for a prescribed time in a growth chamber set at 20° C., 60 % RH and 16L : 8D photoperiod. The dis es containing the con­trol and cryogenic eggs were removed and held in the same growth chamber for hatching of CPB larvae and emergence of parasites. The numb r of eggs in each test varied according to the availability of eggs harvest d from the laboratory colony. The mean % parasitism, % hatch ofCPB larvae and % par­asitism in the control were determined for these data. RESULTS AND DISCUSSION Tests 1 to 9 include a wide range of: preconditioning times from 0 to 144 hours; cryostorage from 11 to 26 days; parasite ages from 3 t  42 days; para­site exposure times from 20-120 hours and number eggs exposed (Table 1). The resulting percent parasitism expressed in the various tests ranged from 5.8 to 17.8%. In one of the cryovials in Test 9, 30.0% of the eggs exposed to EP were parasitized. Although low parasitism rates were obtained compared to the parasitism rate in the controls we were encouraged by the results, since prior to thes  studies no Colorado potato beetle eggs were reportedly placed in cryostorage for use in rearing E. puttleri or any other parasites or predators. This was a study to determine the feasibility of using cry stored eggs for rearing E. puttleri, therefore no detailed biological studies were conducted to determine sex ratios and fecundity of the parasites produced from cryostored eggs. However this study is the first to show that cryostorage/storage a  very low temperatures of Colorado potato beetle eggs for use in r aring the para­site is feasible. Much additional work is required to fully understand the optimal precon­ditioning temperature/time, cryostoragel conventional freezer storage time and what effect all these variables have on the sex ratio and fecundity of the emerging adult parasites. ACKNOWLEDGMENTS Thanks to Ann M. Sidor for her technical support during the course of this research. 2The Great Lakes Entomologist, Vol. 30, No. 3 [1997], Art. 5https://scholar.valpo.edu/tgle/vol30/iss3/5-0 -0 "J Table 1. Differences in % parasitism of cryostored Colorado potato beetle eggs by Edovllm puttleri. Parasitoid % Parnsitism Test # Treated eggs2 Conditioning to,e (hrs)b Cryo time (days) Parasitoid age (days) exposure (hrs) Untreated eggs" of untreated eggs % Control parasitism -l::r: 1 225 0 15 4-12 72 197 5.8 53.0 m Q "'"2 358 4 12 6-19 46 71 6.1 69.0 m ~ 3 691 8 11 4-7 65 22 7.2 72.1 s;: 4 176 144 19 16-40 20 138 7.4 75.4 ?';; m <n 5 649 24 26 23 21 94 8.3 30.0 m Z 6 7 8 501 637 162 24 24 96 12 11 21 6-19 3 18-42 46 24 96 61 26 19 9.0 9.4 10.5 54.0 53.3 73.0 -l 0 3: 0 5 Q 9 321 24 1  11 120 197 17.8 53.0 Vi -l 'Note: All Colorado potato beetle were 0-24 hrs old at beginning of test, except tests 3, 6, & 8 which were 24-72 hrs old. "Treated "" cryostored eggs. bConditioning "" # of hours eggs were held at 5°C. "Untreated eggs not expos d to ultra low temperatures. "J -0 3Schroder: Feasibility of Using Cryostored Colorado Potato Beetle (ColeopterPublished by ValpoScholar, 1997180 THE GREAT LAKES ENTOMOLOGIST Vol. 30, No.4 LITERATURE CITED Drooz, A. T. and J. D. Solomon. 1980. Rearing the egg parasite Ooencyrtus ennomopha­gus (Hymenoptera: Encyrtidae) on eggs of Clostera inclusa (Lepidoptera: Notodonti­dae) kept below freezing. Canadian Entomol. 107: 739-740. Fedde, G. F., V. H. Fedde, and A. T. Drooz. 1979. Biological control prospects of an egg parasite, Telenomus alsophilae Y.iereck. Pp. 123-127. In: Current Topics in Forest Entomology. Selected papers from the XV Int'l Congo of Ent. USDA, Forest Service, Gen. Tech. Rep. WO-8. 174 pp. Lashomb, J. H., Y. S. NgR. K. Jansson, and R. Bullock. 1987. Edovum puttleri Gris­sell (Hymenoptera: Eulophidae), an egg parasitoid of Colorado potato beetle (Coleoptera: Chrysomelidae): development nd parasitism on eggplant. J. Econ. En­tomol. 80: 65-68. Lopez, J. D., V. S. House, and R. K. Morrison. 1987. Suitability of frozen Sitotroga ce­realella (Olivie ) eggs of temporary rearing of Geooris punctipes. Southwest. Ento­mol. 12: 223-228. Maini, S. and G. Nicoli. 1990. Edovum puttleri (Hym.: Eulophidae): Biological activity and response to normal and frozen eggs of Leptinotarsa decemlineata (Col.: Chrysomelidae). Entomophaga 35: 185-193. Schroder, R. F. W. and M. M. Athanas. 1989. Use of the egg parasite Edovum puttleri Grissell (Hymenoptera: Eulophidae) in an IPM system developed for Colorado potato beetle (Coleoptera: Chrysomelidae) control on potatoes, Beltsville, Maryland. Ento­mophaga 34: 193-199. 4The Great Lakes Entomologist, Vol. 30, No. 3 [1997], Art. 5https://scholar.valpo.edu/tgle/vol30/iss3/5

https://scholar.valpo.edu/cgi/viewcontent.cgi?article=1940&amp;context=tgle

Feasibility of Using Cryostored Colorado Potato Beetle (Coleoptera: Chrysomelidae) Eggs for Rearing \u3ci\u3eEdovum Puttleri\u3c/i\u3e (Hymenoptera: Eulophidae)

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