Golfdom, June 2011

Turf M D THE DOCTOR IS IN THE HOUSE O ne of todays hot topics is the development of nutraceuticals 14 Golfdom June 2011 a combination of the words nutrition and pharmaceutical Food used as medicine has the benefit of combining desirable therapeutic effects with reduced side effects associated with traditional pharmaceutical drugs Food was used thousands of years ago as medicine but it wasnt until the 1980s that the modern nutraceutical era was born in Japan Plants have been known for centuries to have medicinal properties One of the earliest reports of that dates back to the preeminent Greek philosopher and doctor Hippocrates who encouraged women in the fourth century B C to chew willow leaves to relieve pain during childbirth Over the centuries the extract from willow was purified and eventually called salicylic acid The demand for this natural painkiller led to the development of synthetic versions that were relatively inexpensive In 1899 Bayer marketed an over the counter version of salicylic acid known by its common name aspirin Although not new the interest in salicyclic acid and other plant beneficial hormones has only taken place in the last 20 to 30 years Salicyclic acid is important as a plant signal or hormone that stimulates the plants defenses in response to a pathogen attack In an oversimplification of the plant disease interaction plants recognize pathogens and mount a defense through the production of specific proteins by host resistant genes If the plant lacks the corresponding pathogen resistant gene it cannot activate its defense mechanism quickly or intensely enough to fight off the pathogen The signaling effect of salicyclic acid becomes apparent when a turfgrass plant has a hypersensitive early defense response to a pathogen attack A hypersensitive response occurs at the point of pathogen entry where the plant sacrifices cells around the infection point producing a lesion in an attempt to isolate the pathogen Not a lot is known about the impact of salicyclic acid on turf Nearly all the research has been done on dicots Research on monocots in general and turf specifically is limited Activating the Plants Defenses by karl danneberger However the application of salicyclic acid its derivatives or associated hormones which are known as plant activators are commercially available in Europe and other places Plant activators like acibenzolar s methyl benzothiadiazole have been tried on rice wheat and several vegetables When applied topically benzothiadiazole has shown some protection against diseases like rust and powdery mildew On turf where research is much more limited benzothiadiazole has shown some promise In a study conducted at Kansas State University researchers found that benzothiadiazole applied during the season could significantly reduce dollar spot compared to an untreated control on various creeping bentgrass cultivars Applications of benzothiadiazole had to be made throughout the growing season Although dollar spot was reduced by the applications no effect was found in reducing brown patch With increased government and environmental pressure on this industry to reduce pesticide use on turf the battle to control diseases will need to be fought a number of different ways One plan of attack is to activate the plants own defense mechanism by applying the appropriate plant activator plant and disease dependent that can reduce the incidence and severity of disease I believe we will see the use of plant activators tested which is already underway in combination with fungicides that may extend the period of control and or reduce the fungicide rate Although that promise is there sound science will be required in order for us to know what the advantages and limitations of plant activators are On turf where research is much mOre limited benzOthiadiazOle has shOwn sOme prOmise Karl Danneberger Ph D Golfdoms science editor and a turfgrass professor from The Ohio State University can be reached at danneberger 1@ osu edu