THE implications are huge for WA farmers, as there is the potential of a cheap management practice to control soil-borne diseases at seeding.
This year farmers using Triadimefon 125, commonly called Triad, have struck problems mainly concerning blockage problems in spray lines and nozzles.
Brothers Burke and Shane Perry, Nyabing and neighbor Simon Hill, Mindarabin, believe they have identified the problem, after testing it in water, and have alerted the manufacturer.
Triad is the cheapest of three well-known fungicides which combat stripe rust and other soil-borne diseases in wheat and barley.
Its only drawback is that it is an emulsifiable concentrate (EC) which comes out of solution in water causing crystalisation and a ³settling out² in spray lines, thus causing nozzle blockages.
The more expensive fungicides are formulated as suspension concentrates (SC) and work well in terms of distribution from tank to nozzle.
While still in the experimental stage, there is great hope that an SC Triadimefon 125 will come into the market to give farmers the option of fighting soil borne diseases at seeding, in a lower cost one-pass system.
This year the trio discovered that Triad reacted to cold temperatures and would crystalise at night or settle out in the lines.
Anti-freeze additives didn¹t work so Shane and Burke tried agitation to keep the Triad mixed through the Flexi-N, while Simon experimented with direct injection of the Triad.
³We were working fairly continuously so we didn¹t get many problems and our lines were short,² Burke said. ³But we heard of others having problems and it might have been longer lines and the loss of agitation in the lines because of the low volumes that are used.²
Simon looked at injecting Triad into the Flexi-N stream on the bar and using the filter as a mixing chamber rather than mixing in the main tank.
He mounted a 200L tank on the side of his Valcon airseeder and employed a gravity-feed system to move the Triad through a John Blue pump to the primary line containing the Flexi-N before the liquid reached the distribution manifolds.
³But we still got problems of crystallisation,² Simon said.
The penny dropped when Simon put water with Triad and discovered the Triad, which is an emulsifiable concentrate, came out of solution.
And as Flexi-N consists of nearly a third water it stood to reason that over a long line, the Triad would come out of solution and settle.
When Simon used another fungicide, Impact (which is a suspension concentrate) in canola, the problem disappeared.
³It¹s not the Triad in the Flexi-N that¹s the problem so much as the formulation,² Simon said. ³It appears the SC formulation is the best option for tank mixing or injection.²
To combat the existing problem, Shane, Burke and Simon are looking at a system of direct injection into the primary liquid nitrogen line at the bar, before dispersion across the bar through a manifold system.
According to Simon, such a system would eliminate worries of tank mixes being left overnight and ³glueing up², fewer problems with antagonistic product mixes and the ability to change the rate of the fungicide on-the-go.
Such a system also could lead to adding different nutrients such as zinc sulphate to the fungicide, to experiment on nutrition additives.
³Achieving a one-pass nutrient and insurance package for broadacre crop establishment has always been possible,² Simon said. ³The inhibiting factor has been cost.
³But now with the emergence of liquid fertilisers and their ability, in most cases nitrogen, to act as a carrier for herbicides, insecticides and fungicides, things have changed.²
Add guidance to the equation and you come up with a set of possibilities that could actually reduce inputs costs while at the same time setting up crops for maximum potential.
³The main point we¹re looking at is achieving more early plant vigour with liquids rather than granular products,² Simon said. ³We have seen this year the crops coming away faster with the liquid mixes and there is an ability for the plant to set up good potential in those early growth stages.
³With granular product you do tend to get a lag effect in the first eight weeks before the crops start to take off.
³This could be a for a range of reasons but we suspect the liquid mixes are more plant available because of the fact that there is no process for the liquid to go through once it¹s in the soil.
³It¹s there for the plant roots immediately whereas you can get interactions with solid product that can actually lock up nutrients like phosphorous, for example, which can contribute to that lag effect.
³The important aspect of having a cheap fungicide is that you could include it at seeding to give the plants the ability to fight off soil borne diseases earlier.
³I can¹t remember a year when we didn¹t have high levels of disease at the base of plants, whether it was septoria tritici, rust, take-all or something like powdery mildew in barley.
³To me drilling fungicide is more efficient and you are using a lower percentage of product to fight potentially big problems.
³And a healthy plant from the start has the ability to cope better with persisting diseases later in the season.²
According to Burke, the use of fungicides at seeding, as opposed to foliar spraying later in the growing season, could become an annual practice for him and his brother.
³It will cost around $6/ha but I regard that as cheap insurance, especially with the increasing prevalence of rust in wheat.
³At the same time, when you¹re seeding, you¹re also adding nutrient mixes so hopefully there¹s no need to go back into the crop and spray to the extent that we do now.
³I think effective use of fungicide at seeding also gives us the potential to go wheat on wheat and put pressures on leaf diseases.
³That¹s one big reason why we are doing this research to see if we can lower disease pressure.
³The consequence of potential chemical resistance sowing wheat on wheat can be managed by rotation and keeping paddocks clean, probably through a wheat-lupin rotation before two years of wheat, before returning to lupins.
³Those sort of rotations would only be on paddocks where you can achieve good weed pressures.²
Burke says that while the research is still in the experimental stages, he believes it is achievable.
³I envisage there will be times we will go back into the crop and spray based on plant tissue tests that might, for example, reveal a trace element or nitrogen deficiency.
³But hopefully we can get to the stage of seeding a crop and coming back at harvest.
³You would still do regular crop inspections but basically the paddock gate would be shut to all machinery while the plant grows.²
The work they have done will be displayed at the inaugural Burando Hill field day at their Mindarabin properties on August 18.
At the field day, farmers will see a variety of paddock trials involving different fungicides and applications, Flexi-N, with and without trace elements in wheat, barley, canola and oat crops.
All crops were established with a ConservaPak seeder and placement of fertiliser will be discussed.