Community Horticulture, Master Gardeners
Senior Research Assistant
South Valley Fields Crops Faculty
Master Gardener Statewide Coordinator
Faculty Research Assistant
Orchard Crops Specialist
Ask an Expert is a way for you to get answers from the Oregon State University Extension Service. We have experts in family and health, community development, food and agriculture, coastal issues, forestry, programs for young people, and gardening.
Q: I have a 4 year old 12,000 gallon koi pond with a large waterfall. I went to clean the waterfall filters and add barley hay for the algae last weekend only to find thousands, maybe millions, of black fly larvae. I scraped the waterfall as best I could and turned the waterfall back on. The koi enjoyed a meal but when I turned off the waterfall the next day, ...