If there were ever a year to prove the protective power of fungicides, 2022 would be it. A long Spring with above rainfall made for the perfect disease storm for all crop varieties and put fungicides to the test.
Below we go over the major crops in our areas and how our main fungicides performed under pressure.
Stripe rust is back! And it returned with a vengeance, with most crops seeing at least some Rust spore pustules. There were varietal differences that were easy to notice. Varieties such as Vixen, Catapult, Chief, Mace and Rockstar were more susceptible, where fungicides needed to be timed precisely to keep them clean (every 3-4 weeks). Varieties such as Scepter, Calibre, Grenade CL and Hammer CL gave us some genetic resistance, but the high-pressure disease year still required some preventative fungicides. It turned out to be a two or three-spray season, with epoxiconazole best used early at GS31 targeted at Eyespot or early Septoria. The second and third sprays were targeted at Rust prevention or reacted to Rust already in the crop. Prosaro and Maxentis were fantastic follow-up products with excellent rust protection and a good ability to dry out and protect leaves from Powdery Mildew.
Powdery Mildew was also heavily present in most areas, especially in dense, high-tillering varieties such as Chief and Sheriff. The long season/spring also provided Powdery Mildew with the opening to move into the crop head, which can cause grain pinching and screenings issues.
Where disease pressure was high, a head wash was required (timed between head emergence and flowering) and helped to stop Powdery Mildew and Stripe Rust from finding their way into the wheat head.
In the future, wheat varieties like Calibre and Brumby will be vital in helping the fight against Powdery Mildew in high-disease areas. Regarding Septoria, crop levels this year were low and caused few problems, primarily due to the significant resources applied for Rust and Powdery Mildew.
Below: Powdery Mildew (L) and Stripe Rust (R) and Rust in heads (B) in Wheat.
Luckily, barley paddocks remained mostly clean from disease for much of this season. Some early propiconazole or prothioconazole were applied to barley-on-barley paddocks for Net Blotch. As crops stayed clean through winter, it wasn’t until later in spring that Leaf Rust and Net Blotch were found in high levels on the YP and lower levels in the MN. Most crops received a premium fungicide at flag leaf or early head emergence stages. Products such as Amistar, Topnotch and Prosaro were the products of choice, and with many now in generic form, the cost-effectiveness was excellent, and higher rates were able to see the crop cleanly through for the entirety of the season.
This year barley saw more environmental issues, such as Brackling* and headloss, causing significant yield loss and harvest issues on the YP (at the time of writing this, we have yet to really start harvesting in Mid-North). Spartacus CL again showed very high levels of Brackling. *Brackling is kinking or buckling of the stem at or near the upper node, affecting the top 1/3 of the plant, and typically occurs as the straw dries out and high winds are received. Fortunately, Maximus CL – a Spartacus CL replacement – showed little to no brackling and also low levels of lodging and headloss.
Strong winds in November also caused Compass and Commodus CL crops to have high levels of headloss and a large amount of crop lodging in thick, heavy crops. Paddocks that were windrowed faired the best, especially in coastal areas prone to strong winds. If conditions like what we saw this year arise again (thick crops and heavy heads), Compass, Commodus CL, and Titan AX varieties may benefit from windrowing to enable easier harvest and reduce yield loss.
Below: Barley Smut (L) and Scald (R)
Thanks to good SDHI chemistry on the seed (Saltro® Duo, ILeVO®), seedling infection from Blackleg was relatively well held this season. That, and most paddocks received a follow-up foliar application – particularly in the higher rainfall areas. Some of the products used were Prosaro®, Aviator Xpro® and Proviso® – all of which provided satisfactory results, with Aviator Xpro® leading the way in terms of performance. But this doesn’t mean paddocks were completely disease free. Even under good management strategies, early Blackleg was present. The presence of upper canopy infection (UCI) was also notable, which under the cooler and wetter conditions leading into spring, built the foundation and allowed UCI to develop.
Canola 2023 – (yes, you need to start thinking ahead already)
With this season behind us (at least from a fungicide point of view in the Mid North), we should start looking towards the 2023 season. With large areas of canola sown this year and an expected large planting in 2023, it’s crucial to revisit the basics to minimise disease prevalence in the 2023 crop. This includes careful consideration of cultivar grown and resistance rating, distance from last year’s stubble, and a fungicide strategy based on the canker cuts taken from this season.
(Tip: A good indication post-harvest is to do canker cuts to monitor levels of infection which can provide a good foundation for planning your fungicide strategy for the following season).
Regarding UCI Blackleg for next year, resources are available to aid in this decision-making process. One helpful tool is the UCI BlacklegCM app (found here) which can assist in the decision-making process through careful considerations, including location, grain price, conditions, disease risk and cost of treatment, among other factors.
Below: Blackleg in Canola
It’s simple; if it rains, throw money at them, and they will throw it back at you at harvest.
As usual with lentils, a wet spring made it perfect for lentil diseases such as Ascochyta, Botrytis Grey Mould (BGM) and Sclerotinia (White Mould). However, thanks to excellent grain pricing, a favourable year, and cost-effective fungicides, many crops received multiple sprays (up to 6) to keep them protected, and if they were well-timed, minimal disease was seen. BGM and Sclerotinia were the most prevalent diseases, with thick, dense canopies not allowing fungicides to penetrate down into the plants to provide protection. Canopy closures with Sumisclex (Procymidone), Miravis Star, or Aviator Xpro gave maximum protection from BGM and Sclerotinia. As for Ascochyta, multiple Chlorothalonil (Echo) sprays were the product of choice, targeting applications in front of forecast rain events to prevent disease spread.
Below: Sclerotinia in lentils (L), Grey Mould (R), and Ascochyta (B,L) and BGM (B,R).
It only took a couple of days for ‘Chocolate Spot’ to be the word on everyone’s tongues. We went straight from low levels to paddocks that were completely black. Growers on the front foot with a robust fungicide program, spraying every four weeks with preventative sprays, seemed to stay the cleanest. However, it is still to be seen what grain quality will be like. We saw mixtures of Carbendazim (Spin Flo) or Procymidone (Sumisclex) with Veritas Opti or Mancozeb, all give good disease protection early in the season. But unfortunately, when put under high pressure, we noticed we weren’t getting the prolonged protection we usually would. Once this became apparent, we moved onto premium products such as Miravis Star and top rates of Veritas Opti and even these products didn’t get the long-gelati we would expect to see. Paddocks around the Mid North saw up to 5 fungicides in some paddocks to try to keep pods clean and filling. Crazy to think we are still seeing the odd flower into late November/early December. With some big seeds in pods, high numbers of pods, and 4+ beans per pod, we are looking forward to hearing what yields you get.
The photos below of a missed strip of Miravis Star in beans (that wasn’t sprayed due to boggy soil) clearly demonstrate the protection that fungicide provides.