Algae control in bentgrass (Agrostis palustris) with DC5772 and Profile

Despite efforts at both cultural and chemical control, the growth of surface algae in fine turf has become a problem for golf course managers nationwide. Most turfgrass management problems with algae occur during the summer when excess irrigation and warm temperatures are combined with high light intensities (2). When the population level is high, algae form a mat of dark green to black slime layer on the soil surface. This mat will cause problems with aesthetics, playability, and cultural conditions. Chemicals presently labeled to manage algae in turf do not meet acceptable control levels. Alkoxysilanes are used for the control of algal growth in water intended for domestic and industrial uses (3). This compound has also been found to exhibit algicidal activity while chemically bonded to a variety of substrates (1,3). This investigation was designed to test the hydrolysis product of an alkoxysilane compound, 3-(trimethoxysily)-propyldimethyloctadecyl ammonium chloride (Si-QAC), chemically bonded to a porous ceramic soil modifier, Profile^™, to control algae in fine turf. Both field trials and laboratory experiments were conducted. The field experiments were set up at two locations and were rated visually. Four rates of Si-QAC (0.0%, 0.01%, 0.1%, 1.0% a.i.) dried to Profile^™ were compared against two fungicides, Daconil Weather-Stik™ and Fore™, and two rates of Algaen-X™. Mist chamber experiments were also conducted in which experimentally treated Profile^™, was inoculated with a suspension of algal cells. A chlorophyll analysis was performed as a means of quantifying the algae present in each treatment. Field research demonstrated the Profile^™ treatments out performed the liquid fungicide treatments in controlling surface algae. However, there was little statistical separation between the Profile^™ treatments indicating Profile^™ alone may possess some degree of algae control. Mist chamber studies showed that amended Profile^™ was able to delay the colonization of algae. It was also noted the 1.0% a.i. caused the Profile^™ to become hydrophobic. Management practices which promote a dry soil surface coupled with a preventative fungicide/algicide program are the only means available to combat surface algae as long as environmental conditions favor their development.

1. Isquith, A.J., E.A. Abbott, and P.A.Walters. 1972. Surface-bonded antimicrobial activity of an organosilicon quaternary ammonium chloride. Applied Microbiology. 6:859-863.

2. Mets, S.P., and P.F. Colbaugh. 1995. Evaluation of Natural Products for Algicide Activity Using a Laboratory Bioassay. Texas Turfgrass Research Reports. 83-85.

3. Walters, P.A., E.A. Abbott, and A.J. Isquith. 1973. Algicidal activity of a surface bonded organosilicon quaternary ammonium chloride. Applied Microbiology. 2:253-256.