Posted 9.26.05 - Lake Jacksonville's war on hydrilla continues.
Jacksonville city officials recently released 750,000 hydrilla flies onto the hydrilla mats on Lake Jacksonville to try to combat the annoyingly invasive plant. And even in a span of time as short as three weeks, the flies are already making some headway.
"I'm seeing damage to the plant matter floating on Lake Jacksonville's surface already," said Texas Parks and Wildlife biologist Richard Ott. "The flies' larvae burrow into the leaves of the hydrilla and feed on the chlorophyll - the plant's cells that turn sunlight into food."
When the plant's chlorophyll is gone, the hydrilla has no way of making food for itself and dies. However, the fly is only effective on the parts of the plant that are at or above the water's surface.
Hydrilla pakistanae have red eyes and are quite tiny, Ott said, so lake residents and visitors may not even notice they're there.
According to the Web site bc4weeds.tamu.edu, 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.
The fly was discovered in Pakistan for the biological control of hydrilla - a prefect job for it since it is known to feed only on hydrilla. The first release of the fly in the U.S. was in southern Florida in 1987, and by 1990 a population was established.
Records from the Texas Waterways Experiment Station show the fly has been released and established in Texas at Coleto Creek Reservoir in Goliad in 1994 and 1995, and at Choke Canyon Reservoir in Live Oak in 1993 and 1995.
This is just one step in the city of Jacksonville's Integrated Pest Management Plan for controlling hydrilla. Other steps include herbicidal treatment twice a year and potentially adding grass carp to the lake habitat.
"I think we're getting the ball rolling in the right direction," said Jacksonville Mayor Robert Haberle.
Source: http://www.jacksonvilleprogress.com/articles/2005/09/15/news/news05.txt
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