With warmer drier summer weather turf managers must be on the look out for the first symptoms of Take-All, warns Simon Barnaby of Syngenta. Turf on recently constructed sand-based greens, tees and sports pitches has proven especially susceptible already this season, he reports, but a number of management practices are likely to have increased the risk on turf surfaces that have not shown the disease in the past.
“Take-All thrives in low fertility situations, especially where the pH is higher and particularly if there is any manganese deficiency,” he advises. “With rainfall well above average in March, April and May, any residual nutrients in the sand rootzone could have been leached away, along with available manganese essential to reduce the effects of Take-All.”
Furthermore, the increased use of non-acidifying fertilisers and irrigation with naturally alkaline water has caused a dangerous rise in pH in the surface layer of some soils. Soil sample reports reveal even on greens with a pH of 6 in the rootzone, can be as high as 8.5 at the soil surface where Take-All can develop.
Mr Barnaby advises that Heritage is the only fungicide approved for the control of Take-All. On turf surfaces where there is a history of the disease, turf managers may opt for preventative applications during high risk periods. But he adds that on other turf, treatment at the first signs of disease can prevent further spread and minimise visual damage or die-back that would affect playability.
Mick Fance of Scotts Professional also advocates turf managers ensure there is sufficient trace element and nutrient availability to encourage healthy regrowth, and minimise any impacts of the disease. Where turf has any history of Take-All, or is growing in a high risk situation, he recommends the granular STEP Hi-Mag should be included in the fertiliser programme. If Take-All has broken out, an application now could help prevent further damage, he adds.
“A number of courses have sought to increase their all-weather playability by constructing sand-based greens in recent seasons,” reports Mr Fance. “They need to be especially vigilant for Take-All where they may never have experienced the problem before.
“All turf managers should check the alkalinity of irrigation water and take soil samples in the surface layers to test the pH, especially if they are using non-acidifying fertilisers,” he adds.
Simon Barnaby points out that Heritage is also approved for the treatment of Fairy Ring that is increasingly being seen on fine turf surfaces. “Basidiomycete fungi responsible for Fairy Ring may have remained viable in the soil organic matter for decades, but only now be creating the visible symptoms during periods of turf stress.
“Turf managers need to avoid turf stress with appropriate nutrition, irrigation and maintenance. Summer applications of Heritage can also help to minimise the development of the fungi and the visual effects of Fairy Ring.”
He advises that for best results, trials have shown that affected areas should be aerated prior to making two Heritage applications, 14 days apart. The addition of a compatible wetting agent, such as Scotts H2Pro will further help to wet the soil and allow the Heritage to get to the pathogen. Applications aimed at Take-All and Fairy Ring should be made at a minimum water volume of 1000 litres per hectare.