The Ohio State University

Home TurfNotes Etiolated or rapidly elongating Poa annua leaves on golf course tees and fairways are appearing under the extended wet cloudy weather that we have experienced for the last month. Etiolated Poa annua leaves appear yellow and tend to extend 2.5 to 5.0 cm above the turf canopy. The leaves eventually become bleached out (white) due to the dilution of chlorophyll in the rapid elongating leaves.

This phenomenon has been reported as Mad Tiller Disease, and Ghost Grass (primarily in the United Kingdom). Recently, the term "Etiolated Tiller Syndrome"(ETS) is being used. The cause of ETS is not well understood or definite reason why it occurs. Speculation on the cause has include bacterial wilt, micronutrient deficiencies and increasingly on the fungus, Fusarium moniliforme that causes similar symptoms in rice. The fungus produces gibberellic acid (GA) - like compounds which is associated with the leaf elongation.

Etiolation - the extension of the leaf blades upward - is a common growth occurrence of plants under low light conditions. It is possible under extended cloudy wet conditions that the leaves elongate in response to the low light conditions favoring infection by F. moniliforme causing the rapid elongation.

There does not appear to be any longterm decline in the density or quality of turf from ETS. Additionally, there are no management practices associated with enhancing or promoting ETS. Research observations at Purdue University have found no associated occurrence or control of ETS with GA inhibiting plant growth regulators (ex. Trinexapac-ethyl, flurprimidol, and paclobutrazol).

Posted by Karl Danneberger