For the second time this season, we’ve whipped around the country and spoken to three agronomists and a pathologist to find out the current issues of the season and the next management strategy to think about.
Steven Simpfendorfer, cereals pathologist from the Tamworth Ag Institute, NSW
Steven Simpfendorfer said a large range in planting times has meant there’s been issues with disease management, particularly stripe rust, with crops sown late under high pressure from early infections.
“At the moment we’re trying to get them to think about adult plant resistance with stripe rust, trying to educate on identifying when adult plant resistance is active, because once the genetics is taking care of it, it doesn’t need the fungicide protection,” he said.
“The other big one we’re really pushing is, particularly with that late plant crop again, the environment has changed because the crop is in so late – a couple of months late. The concern there is around leaf rust, which we know likes warmer conditions than stripe rust.
“With that late plant being so unseasonally out of its window, the real fear is we could have a leaf rust epidemic at stages where the genetics isn’t taking care of it.”
Greg Toomey, Nutrien Elmore, VIC
Greg Toomey said disease-wise, they are starting to see a little bit of stripe rust in wheat, scold in barley, spot form and net form net blotch in barley, as well as sclerotinia and black leg in canola.
“Most of the wheat has had sufficient nitrogen to get it to around 4 to 4.5 tonnes per hectare, and this last rain probably raised our hopes to maybe a 6 tonne wheat crop,” he said.
Greg said nitrogen is still going to be the most important management strategy over the next few weeks, with additional nitrogent required if the season continues the trajectory it’s on.
“We don’t have a great lot of legumes in our rotation at this stage, so in what’s shaping up to be a third good year in a row, there’s not much left,” he said.
“So that’s probably the challenge, is to be brave enough to keep investing when it’s quite expensive this year and particularly as commodity prices have actually receded a little bit, they’re still pretty good, but they’re not at the heady heights that they were a little while ago.”
Sam Holmes, Central Ag Solutions, Yorke Peninsula SA
Sam Holmes said there’s a real mixture of disease in the region, including stripe rust and leaf rust in wheat, wheat powdery mildew and septoria tritici blotch, spot form and net form net blotch, and leaf rust in barley too.
Sam said he’s been telling his clients to make sure they’re on top of the timing of fungicide application if they’re getting close to flag leaf.
“It’s a crucial stage and really trying to make sure we’re on top of the disease rather than letting it get out of control before they can get to it,” he said.
“I’ve probably been quite particular to farmers in the region about making sure we keep water rates up just to try and get really good coverage and penetration, and also making sure they have product on hand, ready to go, as we know we’re in for a reasonable disease season.”
Dan Taylor, DKT Rural Agencies, Central Wheatbelt WA
Dan Taylor said recent rainfall has meant a really good top up of soil moisture levels, however some disease management challenges laid ahead, particularly with wheat powdery mildew.
“We haven’t seen infections for probably five to seven years to this level of significance, so it’s more about product availability,” Dan said.
“And now with our recent rainfalls, I can’t see growers being able to get on paddocks for a good seven to ten days at least, and the availability of planes for spraying is zero, so the diseases are going to be left unchecked in crops until growers can actually get back on paddocks and sort things out.”
Dan said he would recommend growers to get into paddocks that haven’t had any fungicide treatment to this point and determine where the disease is in the canopy, the incidence in terms of leaf area infection percentages, try and get an assessment of how that disease is going to progress in the next two to four weeks.
“Which is probably what I see is the length of time remaining that environmental conditions in our area will be conducive for disease to continue to develop. The horse can bolt on us if we don’t catch that disease early, which is why growers need to be aware of what’s going on now,” he said.
And the final word from CCDM
CCDM Director Mark Gibberd said with conducive environmental conditions around the country, disease challenges are starting to emerge, with moist canopies providing the right conditions for fungal diseases to dominate.
“At this time of year, we know that people will be putting out fungicides to help to control the diseases, which is good advice provided people are following strategies to avoid fungicide resistance,” he said.
“Powdery mildew in wheat is becoming a dominant force in many regions, because the genetics deployed right now don’t have a great deal of resistance.
“But there’s some good news there, we believe that we’ve potentially identified some forms of new resistance that, in the future, will help form the basis of resistant crop varieties.
“CCDM is doing a lot of work in this space as we intend to continue to deliver new genetic solutions for long term disease control.”
Liked this blog? Why not listen to the full interviews on the Crop Disease Podcast