Algaecide or algicide is a biocide used for killing and preventing the growth of algae, often defined in a loose sense that, beyond the biological definition, also includes cyanobacteria ("blue-green algae"). An algaecide may be used for controlled bodies of water (reseviors, golf ponds, swimming pools), but may also be used on land for locations such as turfgrass.

Types

Inorganic compounds

Some inorganic compounds are known since antiquity for their algicidal action due to their simplicity. *

Copper(II) sulfate Copper(II) sulfate, also known as copper sulphate, is an inorganic compound with the chemical formula . It forms hydrates , where ''n'' can range from 1 to 7. The pentahydrate (''n'' = 5), a bright blue crystal, is the most commonly encountered h ...

remains "the most effective algicidal treatment". A related traditional use is the

Bordeaux mixture Bordeaux mixture (also called ''Bordo Mix'') is a mixture of copper(II) sulphate (CuSO4) and quicklime ( Ca O) used as a fungicide. It is used in vineyards, fruit-farms and gardens to prevent infestations of downy mildew, powdery mildew and other ...

, used to control fungus on fruits. *

Hydrated lime Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca( OH)2. It is a colorless crystal or white powder and is produced when quicklime (calcium oxide) is mixed or slaked with water. It has ma ...

, as a biocide, is allowed in the production of organic foods.

Barley straw

Barley Barley (''Hordeum vulgare''), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Globally 70% of barley p ...

straw, in

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

, is placed in mesh bags and floated in fish ponds or

water garden Water garden or aquatic garden, is a term sometimes used for gardens, or parts of gardens, where any type of water feature is a principal or dominant element. The primary focus is on plants, but they will sometimes also house waterfowl, or orn ...

s to help reduce algal growth without harming pond plants and animals. Barley straw has not been approved by the

United States Environmental Protection Agency The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it ...

(EPA) for use as a pesticide and its effectiveness as an algaecide in ponds has produced mixed results during university testing in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

and England. It is unclear how straw actually works. Peinture algicide et fongicide

Synthetic algicides

Synthetic algicides include: *

benzalkonium chloride Benzalkonium chloride (BZK, BKC, BAK, BAC), also known as alkyldimethylbenzylammonium chloride (ADBAC) and by the trade name Zephiran, is a type of cationic surfactant. It is an organic salt classified as a quaternary ammonium compound. ADBACs ha ...

– "quat" disinfectant that attacks membranes * bethoxazin – "new broad spectrum industrial microbicide" in 2012, noted as "Canceled in U.S." in 2022 PubChem-EPA query * cybutryne – banned since 2023 in ship paint * dichlone – quinone fungicide/algaecide, not persistent in soil * dichlorophen – also kills invertebrate animals and bacteria *

diuron DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is an algicide and herbicide of the arylurea class that inhibits photosynthesis. It was introduced by Bayer in 1954 under the trade name of Diuron. History In 1952, chemists at E. I. du Pont de N ...

– herbicide/algaecide, inhibits photosynthesis *

endothal Endothall (3,6-endoxohexahydrophthalic acid) is used as an herbicide for both terrestrial and aquatic plants. It is used as an aquatic herbicide for submerged aquatic plants and algae in lakes, ponds and irrigation canals. It is used as a desicc ...

– herbicide/algaecide, inhibits

protein phosphatase 2A Protein phosphatase 2A may refer to: * Protein phosphatase 2 Protein phosphatase 2 (PP2), also known as PP2A, is an enzyme that in humans is encoded by the ''PPP2CA'' gene. The PP2A heterotrimeric protein phosphatase is ubiquitously expressed, ...

fentin Fentin acetate is an organotin compound with the formula (C6H5)3SnO2CCH3. It is a colourless solid that was previously used as a fungicide Fungicides are biocidal chemical compounds or biological organisms used to kill parasitic fungi or their ...

– quinone fungicide/algaecide, discontinued * isoproturon – selective substituted urea herbicide, discontinued * methabenzthiazuron – substituted urea herbicide, discontinued * nabam – fungicide/algicide discontinued in the EU over cancer *

oxyfluorfen Oxyfluorfen is a chemical compound used as an herbicide. It is manufactured by Dow AgroSciences and Adama Agricultural Solutions under the trade names Goal and Galigan. Oxyfluorfen is used to control broadleaf and grassy weeds in a variety of nut, ...

– herbicide, "very toxic to aquatic life with long lasting effects" * pentachlorophenyl laurate * quinoclamine – herbicide/algicide, not used in most of the EU * quinonamid *

simazine Simazine is an herbicide of the triazine class. The compound is used to control broad-leaved weeds and annual grasses. Preparation Simazine may be prepared from cyanuric chloride and a concentrated solution of ethyl amine (at least 50 perce ...

– herbicide/algaecide, inhibits photosynthesis * terbutryn * Tiodonium

References

{{reflist

External links

National Pesticide Information Center (NPIC)
Information about pesticide-related topics.