St. Augustinegrass, Stenotaphrum secundatum (Walt.) Kuntze, the most widely distributed lawn grass in Florida, has aggressive stolons forming a tight canopy (Busey, 1989) resistant to weeds. Under adequate moisture and proper mowing, St. Augustinegrass is usually the climax species in south Florida lawns. Despite the importance of proper maintenance and weed control, only one scientific papers deals with the relationship of maintenance practices and weed control. Colbaugh and Knoop (1989) showed that broadleaf weed populations were greater where clippings were recycled compared to plots where clippings were removed. Sometimes over-watering is associated with infestation by matchweed, Phyla nodiflora (L.) Green, and dollarweed. Sedges (annual sedge, Cyperus compressus L.; flatsedge, Cyperus odoratus L.; globesedge, Cyperus globulosus Aubl.; Texas sedge, Cyperus polystachyos Rottb.) remain a frequent problem in St. Augustinegrass. Secondary weed problems in St. Augustinegrass are asiatic pennywort, Centella asiatica (L.) Urban; creeping beggarweed, Desmodium incanum DC.; Florida pellitory, Parietaria floridana Nutt.; matchweed, Phyla nodiflora (L.) Green; southern sida, Sida acuta Burm. F.; white clover, Trifolium repens L.; and various Rubiaceae, e.g. Old World diamond flower, Hedyotis corymbosa (L.) Lam.

Special weed problems occur periodically in St. Augustinegrass grown for sod. For example, new weeds such as red sprangletop and alligatorweed have appeared during the last 10-15 years (Busey, unpublished data). Blanket crabgrass, Digitaria serotina (Walt.) Michx., and smallflowered Alexandergrass, Brachiaria subquadripara (Trin.) A. S. Hitchc., are becoming much more serious problems on sod farms. Sod producers and golf course superintendents expect torpedograss to become a much more serious problem in the future. Other new weeds are expected to adapt to the turf environment.

References

Busey, P. 1989. Progress and benefits to humanity from breeding warm-season grasses for turf. p. 49-70 in: D. A. Sleper, K. H. Asay, and J. F. Pedersen (eds.). Contributions from breeding forage and turf grasses. CSSA Spec. Publ. 15, Crop Science Society of America, Madison, Wisconsin, USA.

Colbaugh, P. F. and W. E. Knoop. 1989. Influence of clippings recycling on weed and disease incidence in St. Augustinegrass and bermudagrass. pp. 249-251 In: Takatoh, H. (ed.). Proceedings of the Sixth International Turfgrass Research Conference, Tokyo, Japan. 31 Jul. 1989. International Turfgrass Society and the Japanese Society of Turfgrass Science. Tokyo, Japan.

27 October 1998