Biology
The larvae of these flies mine the leaves of hydrilla plants.
Due to their short life cycle, approximately 20 days, there
was initially some problems with establishment. The basic
biology of the two species is quite similar.
History
Hydrellia pakistanae was discovered in Pakistan
for the biological control of hydrilla. The first release
of the fly was in southern Florida in 1987 and by 1990 a population
was established. A summary of the releases and recoveries
in Florida is found in Center et al. (1991). It has been released
and established in Texas.
Known Release History of Hydrellia
pakistanae in Texas
| Site
|
County
|
Release
Dates |
# of Releases
|
Specimens Released |
Established |
Coleto Creek Reservoir |
Goliad |
6/94-7/95 |
9 |
19,584 |
Yes |
Choke Canyon Reservoir |
Live Oak |
1/93-3/95 |
29 |
169,317 |
No |
* Information provided by the
Waterways Experiment Station.
Management
The adult flies are often released into a cage on top of
a mat of hydrilla. This allows the adults to lay eggs with
a minimum of disturbance from outside predation. The cage
is typically removed in a week or two.
Weeds Affected
Hydrellia pakistanae is known to feed only on hydrilla
(Buckingham et al. 1989).
Literature
Buckingham, G. R. 1988. Reunion in Florida – Hydrilla,
a weevil, and a fly. Aquatics 10(1): 19-25, illus.
Buckingham, G. R., E. A. Okrah and M. C. Thomas. 1989. Laboratory
host range test with Hydrellia pakistanae (Diptera:
Ephydridae), an agent for biological control of Hydrilla
verticillata (Hydrocharitaceae). Environ. Entomol. 18(1):
164-171.
Center, T. D., F. A. Dray, Jr., and W. C. Durden. 1991. Release
and Establishment of Insect Biocontrol Agents for Hydrilla
Control. Waterways Experiment Station, MP A-91-3.
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