TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Bacterium: (I) Is a Gram negative rod-shaped bacterium (especially bacterium SG-3), produces yellow colonies when streaked on growth medium supplemented with tryptic soy broth and solidified with 1% w/v agar, exhibits flagellate motility, has a 16 S rRNA gene sequence substantially homologous to the sequence (S1) of 1540 bp fully defined in the specification, and reduces the chlorophyll alpha content of the water containing the cyanobacterium and alga. (I) Is phylogenetically related to Xanthomonas spp.. The cyanobacteria are at least one of the Anabaena spp. and Oscillatoria spp..Preferred Method: The pathogenic virus is cyanophage LPP-1 (ATCC 18200-B1). WIDER DISCLOSURE - Also disclosed are:    (1) an anti-algae or anti-cyanobacterial composition comprising Bacterium SG-3 and a pathogenic virus such as Cyanophage LPP-1; and    (2) producing the Bacterium SG-3.    ACTIVITY - Herbicide.    Application of the bacterium SG-3 to pond water containing cyanobacteria and algae was performed to study the effect of bacterium SG-3 on naturally occurring blooms of cyanobacteria. Polypropylene tanks (800 l) were filled with water (600 l) from a commercial channel catfish pond (which contained a bloom of cyanobacteria in which the dominant species was a coiled form of )Anabaena spiroides), with lesser numbers of a Microcystis aeruginosa and Oscillatoria agardhii). Inoculum of bacterium SG-3 consisted of three-day-old shake flask cultures that were grown in 4 l flasks (2 l of growth medium/flask). Treatments consisted of 2 l of bacterium SG-3 inoculum/tank. Controls received 2 l of growth medium only. No aeration was used and no fish were included in this experiment. The effects of the bacterium on bloom density and species composition were determined by visual observations and by microscopic examinations. Dissolved oxygen, conductivity and temperature readings were made. A portable pH meter was used to make on-site measurements. Initial water temperature was 29.7 degrees C, pH was 8.0-8.2, and dissolved oxygen readings was 7.5-8.0 ppm. On the morning of day 2, the dissolved oxygen in the control tanks was 3.3-4.5 ppm and in the treated tanks was 0.2-0.6 ppm. Four days after application of bacterium SG-3, the temperature of the water was 31 degrees C in all tanks. The pH of water in control tanks was 9.0-9.4 and in the treated tanks ranged from 8.2-8.9. The dissolved oxygen in controls were greater than 15 ppm and in the treated tanks was 9.5 to greater than 15 ppm. Water in the control tanks had a thick, dark green scum floating on top. The water column in the control tanks was blue-green. Dominant phytoplankton consisted to abundant Anabaena sp. with lesser amounts of Microcystis sp.. Water in the treated tanks was much clearer than the controls, and no scum was present. Microscopic examinations confirmed the absence of the Anabaena sp., and the presence of Microcystis sp.. Thus the results demonstrated that bacterium SG-3 selectively controls cyanobacteria in mixed population of cyanobacteria and algae.    MECHANISM OF ACTION - Inhibitor of the growth or proliferation of cyanobacteria, algae or undesired bacteria.    ADMINISTRATION - Administered as sprays, dusts or granules directly to the body of the water. No dosage given.    EXAMPLE - Filaments of Oscillatoria cf. chalybea growing as shake flask cultures were immobilized in gel beads of calcium alginate, and was placed in small bags constructed from fiberglass window screen. The tops of the bags were secured with monofilament fishing line. The bags containing the beads were placed in a sampling device constructed of perforated plastic pipe (3.2 x 30 cm) that was capped on each end, with one cap threaded for ease of removal. After incubation at a sampling site (3-5 days), such as a fresh water pond, the beads of immobilized cyanobacterium were returned to the laboratory, removed from the sampling device, and placed into cultures of Oscillatoria cf. chalybea. The presence of lytic agents was indicated as zones of clearing in lawns or by destruction of filaments and cells in the shake flask cultures. The bacterium SG-3 obtained from the sampling device was sub-cultured from lysate produced from inoculated shake flask cultures to form progeny of the bacterium SG-3. Standard procedures were used to select single colonies from bacterial streaks that were made on BG-11 medium that was supplemented with tryptic soy broth (6 g/l) and solidified with 1.5 % agar. After isolation, the bacterium was maintained and evaluated using this medium.