Algae Control in Ponds
Contact: Dan Terlizzi
Controlling algal growth on ponds is a top priority for the Water Quality Focus Team. One area of concentration is developing alternatives to pesticides, which can add nutrient loads to the Bay.
Barley Straw: An Alternative to Pesticides?
Collaborative research between University of Maryland Extension, Sea Grant Extension, and Hood College has demonstrated that barley straw extracts inhibit some forms of fresh water algae. The group has shown that:
-
Barley straw inhibits harmful algal species found in the Chesapeake and coastal bays, including Microcystis, Karlodinium micrum (responsible for fish kills in the Chesapeake and now worldwide), and Aureococcus (the cause of "brown tides” which interfere with shellfish feeding and with photosynthesis in submerged aquatic vegetation or SAV).
-
The inhibitor(s) in barley straw is a large molecule belonging to a chemical class called phenolics. Small phenolics have been used as antimicrobials for a long time -- the active ingredient in Lysol disinfectant is a phenol. The ability of larger phenols (referred to as tannins) to inhibit some algal growth is a more recent discovery.
As a result of outreach components associated with this research, over 300 aquatic managers received training in the use of barley straw for aquatic management. This effort has resulted in an estimated 30 percent increase in the use of barley straw for aquatic management and about 15 percent increase in preventive methods for aquatic weed management.
Although there has been a surge of commercial products based on barley straw, some uncertainty still exists about its efficacy. The Water Quality Focus Team has now initiated a national survey to solicit feedback on this question.
