Dedicate FORTE Stressgard Label Update

Over the last few years, apatch disease has developed on Kikuyu turf. Disease development tended to occur between autumn and spring, with symptoms  being  very  large patches of affected turf. Examination of samples found the roots to be severely infected with Rhizoctonia solani. This pathogen is commonly referred to as Brown Patch and is known to cause disease on a range of turfgrass species.

In the USA and parts of Asia, a specific form of Rhizoctonia solani, known as AG 2-2 LP, cause a patch disease called Large Patch in a range of warm-season turfgrasses including Couchgrass, Zoysia andKikuyu. It attacks slow-growing, warm-season turfgrass in cool, wet weather, and is most common on turfgrass that is semi-dormant or turfgrass that is going into or emerging from dormancy. In temperate climates the disease is most active in the autumn and spring, whereas in tropical climates the disease can be continuously active autumn through spring. Damage can persist through cool, wet conditions and often lasts until warmer spring or summer conditions allow for recovery and active regrowth of warm-season turfgrass.

Rhizoctonia  from samples collected in South Australia have undergone DNA sequencing and confirmed the pathogen is the AG 2-2 LP variant. Samples from Western Australia are still undergoing testing, but it seems that these are also the large patch variant.

Dedicate FORTE Stressgard label has now been updated and registered for the control of Large Patch. The new approval from the Australian Pesticides and Veterinary Medicines Authority (APVMA) allows Dedicate FORTE  Stressgard  to be used on Large Patchin range of warm-season turfgrasses including Couchgrass, Zoysia and Kikuyu.

“This is good news for Turf Managers struggling to control outbreaks of Large Patch on their turf surfaces. Trials of Dedicate FORTE on the disease have seen strong results and I’m interested to see how it supports Turf Managers struggling with disease particularly on sports fields.”  said Jyri Kaapro, Development Specialist at Envu. 

From an integrated disease management perspective, Jyri recommends the first step in reducing Large Patch is cultural steps. “Improve drainage wherever possible, as saturated soil conditions exacerbate large patch. Regular aeration in summer will reduce compaction and risk of having water-logged soils. Minimise late-summer/autumn nitrogen applications”, Mr Kaapro advises.

“DMI fungicides such as Dedicate Forte Stressgard, are the preferred mode of action for soil-borne pathogens like this. Applications should begin in the autumn as the soil temperature drops to 22-24°C, with a second application 28 days later. Application can be made in the spring when turf begins active growth”,  Mr Kaapro recommends.

For  more information on Dedicate FORTE  Stressgard, visit the Envu  website.