Golfdom, April 2010

Dollar Spot Control Continued from page 25 26 Golfdom A p r i l 2 0 1 0 Whatever reasons for the success more and more superintendents are buying into the earlyapplication method Somehow were affecting how the fungus works with the grass plant Boehm says When conditions are right for dollar spot to emerge the temperature is between 68 degrees Fahrenheit and 86 degrees F according to Boehm But it can still survive and might be doing the most damage at temperatures below 68 It doesnt like it less than 42 degrees Boehm says Were not sure what its doing between 42 and 68 degrees but the chance is its growing Boehm says the optimum time to put down the initial spring application is soon after fairways have been mowed for the second time Fall applications probably work just as well as spring ones but its more difficult to know when to apply Its easy to predict when youre going to break dormancy he says Its difficult to predict when youre going dormant Whatever the reasons for the success more and more superintendents are buying into the early application method Dennis DeSanctis a territory manager for Syngenta Professional Products in the Northeast estimates that about 50 percent of his customers now put down a spring application Its been a trend going on for the last five years De Sanctis adds adding a reason for this is more and more resistance issues shown by dollar spot the most troublesome disease on cool season turf Boehm says hes happy superintendents are trying the method and monitoring the results rather than just listening to the sage on the stage as he refers to himself and others who lecture at education seminars It just validates all the work were doing he adds Many superintendents however are sticking with the method of frequent summertime spraying In Pennsylvania Mathews says hes touting the program and has let others know hes saving money and controlling the disease better than ever But those superintendents still dont change They havent bought into it because they have the budgets Mathew says of many of his brethren at courses with money But Mathews says he has been questioned about it more in recent years as budgets have been cut Mathews also admits that making the switch can cause consternation Its a little scary he says There are some superintendents like Mike Stachowicz at Dedham Mass Country and Polo Club who experimented with the spring application and missed out on the desired results It didnt seem to help me when I needed it most he says although he admits he remains intrigued by the early spraying regime and may experiment with it again For those looking to see if the spring or fall application will help their courses Boehm suggests this strategy First determine which fairways are most affected by dollar spot and choose one for the experiment Second cover a 4 foot by 4 foot section at the end of the fairway nearest the tee with 2 feet on either side of the midpoint so that an unsprayed control zone is created Next spray half the fairway in early spring again covering the 4 foot by 4 foot section From there the superintendent should follow his or her normal spray regimen remembering to cover the control area On the second application dont apply to an area one boom width in from the end of the fairway nearest the tee On each subsequent spray move in one more boom width As a result the chemical will not have been applied four boom lengths in from the tee end of the fairway by the fourth application The final step is when dollar spot does hit starting at the green end the superintendent should drive down the middle of the fairway to look for symptoms of the disease noting when he sees the beginning of satisfactory control Boehm says The superintendent should also look to see if theres less dollar spot on the side of the fairway that received the spring application Also at the end of the fairway nearest the tee he or she should check to see if the pathogen is still being controlled in the area that received fewer applications than normal Often times superintendents will realize even if they dont want to switch to putting down a fungicide in the spring that they can still get away with fewer applications Boehm says Early season applications to control dollar spot could have a far reaching impact on golf course maintenance as a whole Understanding the biology and ecology of the fungi is key to moving IPM on golf courses to a whole new level Boehm adds Pioppi is a contributing editor to Golfdom and is based in Middletown Conn