On the basis of present evidence, morphactins, used at low rates, appear to have some regulatory effects on turfgrass growth—stimulating seed yield and flowering, and affecting tillering and degree of culm elongation. However, reductions in leaf growth from morphactins, do not indicate specific growth regulation but appear to be caused by phytotoxicity. Such poisoning generally leads to lowered vigor and reduced ability to recover from wear, insect, and disease attacks, and may increase susceptibility to disease and insects; therefore, the continuing recommendation is for replacement of hybrid bermudagrasses when used for purposes to which they are not suited. When a brown color is not objectionable, a considerable reduction of thatch and clippings can be obtained by withholding irrigation and fertilizer.

Tifgreen bermudagrass for this experiment was donated as sod by Nunes Turf-grass Nurseries, Inc., Patterson, California.