Fusarium patch caused by the fungus Microdochium [Fusarium] nivale is the most widespread, frequent and damaging disease of professional sports turf from the highlands of Scotland to the south coast of England. Four fifths of all fungicide sprays to turf in the United Kingdom are targeted against Fusarium. Nine out of every ten green keepers expect to deal with the disease in any one year and none more so than Alan Sharp head greenkeeper at Scotscraig Golf Club at Tayport Fife in Scotland.
Disease was rife across the greens at Scotscraig when Alan arrived in 2006 from his previous position in Essex. "Fusarium was bad", says Alan "with patches on some greens as big as 'dinner plates', but we cleaned up the greens in a season using a spray programme combining two fungicides. Alan is always looking for new and improved approaches and believes he has found one, after taking part in a 2007 autumn trial with a new fungicide product called 'DEDICATE®' from Bayer Environmental Science.
Dedicate is a contact and systemic fungicide with preventative and curative action for fast-acting, long-lasting disease control. Dedicate fungicide is a convenient and easy to use flowable liquid formulation for turf disease control at low volume rates.
Alan carried out direct comparison of Dedicate with a proprietary systemic strobilurin fungicide, ensuring other inputs including fertiliser and nutrients were universal and constant to all greens. Swards are very old and 65% bent/25% Poa Annua/10% other in species composition. Greens are on a light free-draining sand base derived from natural soil.
First preventative application was made on 3rd September 2007 on a still fine day with Dedicate sprayed on the back 9 greens and the systemic strobilurin to the front 9 plus putting green. Both treatments were applied with a Gambetti sprayer (400 litre capacity tank) rear-mounted on a Cushman. The 7.5 m boom accommodates 12 nozzles.
Dedicate went on comfortably at 1 litre of product in 350-400 litres of water per hectare, while the 500 g of solid strobilurin per hectare required twice the volume rate at 800 litres of water per hectare. Observations made on 25th September showed no evidence of disease on any of the greens. Following several weeks of relatively high disease pressure second applications of Dedicate and the strobilurin fungicide were made on 23 rd October.
By 2nd November greens sprayed with Dedicate were still completely free from Fusarium but those sprayed with the systemically-acting strobilurin were showing small patches of mottling, the early tell-tale signs of Fusarium patch disease. The front 9 and putting green were sprayed for a third time with the strobilurin fungicide. Final assessment on 5th November showed no signs of disease on the Dedicate-treated greens but scarring of the turf on greens treated with the strobilurin fungicide.
During the ten days between the second spray (23rd October) and the disease assessment on 2nd November all greens experienced unprecedented disease pressure. These still warm but fast shortening days, with rapid cooling to give night-time temperatures down to 5-6ºC, produced exceptionally heavy morning dews ideal for Fusarium spread and development.
Such conditions and consequent disease pressure had clearly overcome the systemically-acting strobilurin fungicide but the fast, broad-front action and durability of Dedicate overwhelmed the Fusarium pathogen during this period of exceptionally high disease pressure. The back 9 greens treated with Dedicate included 15 and 17 that always experience higher Fusarium disease pressure being surrounded by gorse that impedes air circulation.
Alan was clearly impressed with the control achieved by Dedicate commenting "its longevity was truly remarkable during this spell of very high disease pressure. I know for a fact that neighbouring courses were experiencing disease problems and having to spray at this time", said Alan. "I am all the more impressed because conditions in Scotland at this time of year are ideal for Fusarium, but not particularly good for grass growth and therefore the activity and efficacy of purely systemic fungicides.
But the comprehensive control by Dedicate did the trick. On Scotscraig greens in particular with free draining light soil exposed to high rainfall Dedicate did exceptionally well to 'stay on' under inherently high weathering pressure through good rainfastness."
When the numbers were added up practical benefits and advantages of Dedicate really shone through. "It is so convenient says Alan. One litre of 'Dedicate' was simply poured into the tank with 400 litres of water, providing sufficient spray to treat all 18 greens plus the putting green, with just enough left over to protect our two 'chipping' greens".
The sprayer was operated at very low pressure using blue nozzles to apply a low volume (350-400 litres of water per hectare) of Dedicate spray compared with higher sprayer pressure and white nozzles required to apply double the spray volume (800 litres of water per hectare) of the strobilurin fungicide. Similarly the solid strobilurin formulation had to be weighed out in two lots of 250 g to cater for two fills of the 400 litre sprayer tank, leaving a half empty bottle of pesticide for storage.
According to Alan the key benefit of Dedicate was the one less spray required, which produced a chemical cost saving for one application over the whole course plus increased flexibility in labour scheduling. "On this basis 'Dedicate' is providing a nice little insurance policy with good disease control while saving money at the same time", claims Alan.
Scotscraig, an 'Open Qualifying Course', is a good members club and increasingly popular. Year on year records for Green Fees were broken in 2005, 2006 and 2007 with a 45% increase over the period. As head greenkeeper, Alan Sharp cannot afford even a hint of turf disease on his greens and certainly does not welcome any at all.
"Fusarium is a continual threat says Alan. Conditions experienced during the second half of October through November completely favour the fungus but become increasingly difficult for fungicide control. I require a fast acting fungicide I can get on early knowing it will prevent Fusarium, and carry on protecting the turf through the following period of exceptionally high disease pressure. I think I have found the answer in 'Dedicate' its longevity is truly remarkable."
Fortunately Alan Sharp will not have to wait long to maintain the high level of disease control across his greens with Dedicate, because the product becomes commercially available in January 2008. Dedicate will be sold in versatile 250 ml packs allowing convenient access and easy additional use by smaller users. Apart from Chipco Green, Dedicate is the only contact acting turf fungicide approved for use through a knapsack sprayer.
Further information from:
Bayer Environmental Science,
230 Cambridge Science Park,
Tel: 01223 226 680
Fax: 01223 226 635