P&PDL Logo


The P&PDL Picture of the Week
for 17 February 2003



Shore Fly and Fungus Gnat

Cliff Sadof, Entomology Department, Purdue University

If you are noticing small black flies around your house plants you could be watering them too much. Two kinds of flies, called fungus gnats and shore flies can thrive on continuously damp soils. To prevent these problems, allow your soil to dry between watering.

Shore flies superficially resemble house flies. As the name implies they are found on the shore lines of ponds where they feed on algae. In your house plants adults and larvae feed on algae that grows when you overwater the plants. Shore flies are mostly a
nuisance.

Fungus gnats are more slender and gnatlike. They feed on fungi that grow on soil. Occasionally the maggots will also feed on plant roots spreading disease. For greenhouse growers fungus gnats can be a serious pest.

For more information consult this website: http://www.entomology.umn.edu/cues/inter/inmine/Fliesc.html

Click on the small image to view a larger image.

Shore Fly and Fungus Gnat

Photo courtesy of: Jack Kelly Clark, University of California

Back to top of page | Past Pictures of the Week Index


Last updated: 17 February 2003/amd
The Plant & Pest Diagnostic Laboratory at Purdue University