Rhizoctonia costs Australian wheat and barley growers $150 million a year. Gerri the NVT Guru discusses how soil-borne disease thrives in stubble and stressed plants, and how GRDC-funded trials found mouldboard ploughing and new fungicides cut inoculum four-fold and boosted yields by 0.4 t/ha.
Questions this video answers
Approximately $150 million in yield loss annually.
Started in 2022 and ends in July 2025.
About 0.4 t/ha yield improvement and a four-fold reduction in Rhizoctonia inoculum in soil.
Chapters
Rhizoctonia is a soil borne disease and it survives in the soil primarily in stubble and root tissue. For farmers in Australia it causes a huge impact and it's in the vicinity of $150 million for wheat and barley in yield loss annually. It causes more issues in certain soil types and environments. So low medium rainfall zone is one of the drivers for more pronounced impact because there's less rainfall and the plants obviously are more stressed and struggle with the presence of the pathogen. But soil types that are non wetting, they're often very bad for rhizo.
Over recent years, GRDC Grower Network members indicated that Rhizoctonia is a serious issue with observations that every paddock has some level of disease damage.
We have demonstration trials and we show the different treatments that we put in place with the grower groups, but we also show them what the disease looks like as well. And that's the primary thing, is always to know what disease you have, because without knowing what you have, you can't put a management strategy in place.
So the typical symptoms of Rhizo Zactonia is bare patches, which is you can see it in the buttock. It's better to dig in and can see the root itself to see the symptoms as well as you can tell from the heights of the plants. Or we have the healthy plants and unhealthy and you can see the difference in the length as well as the heads itself.
With GRDC investment, the Department of Primary Industries and Regional Development in Western Australia is developing disease risk and management strategies that are practical and economical for growers to reduce the impact of Rhizoctonia in the southern and western cereal growing regions.
We are farming at East Broom Hill and we are farming 4,000 hectares, 2,800 hectares of crop and remaining as pasture. Rhizoctonia does have an impact here on farm. We do spend quite a bit of money in trying to counteract it and suppress the disease. It takes time to suppress a Rhyscutonia. You've got to put seed dressings on it either at seeding or pre seeding and fungicides at seeding. So it all takes time and time's money.
So within this new Rhizoctonia project, what we're trying to basically achieve is providing new management options and communicating those so that farmers are confident to employ the new management strategies and also to help them identify Rhizoctonia and the issues that it causes.
With support from csiro, the University of Adelaide and Crop Disease Solutions, DPIRD is working to create an integrated and cost effective approach of cultural, chemical and biological management strategies.
Firstly, we are trialling new chemicals, so that includes new fungicides, but also new biological products that are currently in Australia. And then secondly is around the soil amelioration, so applying things like mouldboard, plough, ripping, spading, all those sort of different heavy duty amelioration that growers are starting to do and then providing data and what it's doing to the Rhizoctonia. So we'll get the farmer to put some strips into the paddock which has riser and then we had plus and minus the grizzly plow next to each other. And later in the year we came back and we definitely saw a big improvement in terms of yield response. So we got I think a 0.4 hectare yield improvement tonne per hectare. We got a reduction in four fold in the Rhizoctonia inoculum in the soil. We've got long coleopteryl demo trials as well. And the idea of that is obviously with long coleopters you're sowing deeper in the soil and risers are sort of active in that 0-10 cm. So by sowing below where the riser is active and causing damage on the roots, we can potentially avoid a lot of damage and the plant can get ahead and produce a better yield.
Ultimately, the project will provide a greater understanding of the true economic impact of Rhizoctonia and subsequent thresholds for disease management solutions.
This project started in 2022 and it's ending in July 2025. So 2024 is our final in crop trial period and so we will have results coming out sometime in July, in 2025. And also hopefully we will get a basic grower decision support tool as well around that. So to give them some idea of what type of strategies that we've developed in the project, they can utilise on their farm and know what dollars in a sense are attached to those decisions.
