Stacked DMIs – Stacking DMI’s providing early season disease control in wheat
ADAMA NZ Portfolio Manager Hamish Mulcock says the stacked chemistry of DMIs provide the extra-level robustness that cereal protection toolboxes need in the era of increasing fungicide resistance.
DMI stacking (also known as triazole stacking) is where two DMI fungicides (Group 3) with different cross resistance profiles are applied together. These are used to control fungal diseases including Septoria (Zymoseptoria tritici or speckled leaf blotch) in wheat, Ramularia (Ramularia collo-cygni) in barley, and Eyespot (Pseudocercosporella herpotrichoides) in a variety of cereals.
Hamish says for the stacked fungicides to provide a real benefit it is important that they have different cross resistance pathways.
Bolide® features an innovative combination of stacked epoxiconazole and prochloraz – complementary DMI actives. Hamish explains that, in the DMI fungicide ‘Group 3’, epoxiconazole is categorised as part of the Triazole chemical family, while prochloraz is in the Imidazole chemical family.
He says that within a disease population such as Septoria there are a range of isolates with varying sensitivity to DMI fungicides. “The benefit of ‘stacking’ DMIs with different cross resistance pathways, is that isolates insensitive to one DMI may be controlled by the second. New Zealand trials results have demonstrated that the Bolide co-formulation provides increased efficacy and yields when you compare it with applying similar DMIs solo.
“Bolide has proved an excellent solution to control Septoria, Ramularia and Eyespot, all serious threats to cereal crop yield.”
The all-rounder DMI fungicide is taken up via the stem and foliage and translocated upwards and outwards, providing protection for new growth.
DMIs should be considered the backbone of Septoria fungicide programs in wheat Hamish says. “Bolide provides an excellent, and flexible option providing early season disease control at either the T0 or T1 timings.”
At T0 timing, in wheat, Bolide gives early season preventative Septoria control in susceptible varieties and during wet seasons.
“Bolide also has an excellent fit at the T1 timing with critical protection of leaf 3 as it emerges. Tank mixing Bolide with Phoenix® at T1 timing is encouraged to further boost efficacy and enhance resistance management.”
As Bolide combines protectant, curative, and eradicative properties it is also an option for later season diseases including rust, powdery mildew and ear disease complex.
“Stacking DMIs is vital for further reducing the risk of fungicide resistance. To complement this, we’d also recommend growers have an Integrated Disease Management approach to fungicide resistance including selecting cultivars with high disease resistance ratings, cultural control measures including crop rotations, sowing dates, irrigation and general crop hygiene, mixing with multisite fungicides such as Phoenix (folpet) and rotating strategic use of at risk chemical groups like SDHIs.”
Phoenix, (Phthalimide – Group M4) is a multi-site protectant, which works against Septoria at a cellular level on three sites. Currently there is no known resistance to folpet anywhere in the world. Hamish says Phoenix also enhances DMI uptake, increasing their speed of action and efficacy.
“In terms of cereals and combatting resistance, Bolide and Phoenix are ideal partners in a tank mix.”
Phoenix works against Septoria and Ramularia at a cellular level, inhibiting spore germination and cell division, and reducing energy production in the mitochondria.
Wetter seasons have increased Septoria pressure in wheat through late winter and early spring. “Uncontrolled Septoria is still a real risk to yields, especially in the more susceptible varieties. What’s important here, is to think about how we protect both new and existing chemistries and to learn from our own and overseas experience.”
Hamish says the speed and complexity of mutations in Septoria and Ramularia have challenged cereal growers globally for over a decade. Plant breeding for increased disease resistance is key but this still needs to be complemented with diligent stewardship of new and existing chemistries.
And Septoria and Ramularia aren’t the only cereal diseases where Bolide has a lot to offer.
“Bolide is also an excellent fit for controlling Eyespot, where required, at T0 timing.”
Eyespot is a common disease affecting wheat, barley, oats, rye, and triticale. Effective control is particularly important in susceptible cultivars and where there is elevated disease pressure - for example - in second year wheat paddocks.
For more information on Bolide or Phoenix contact your local Rural Supplier or ADAMA Commercial Manager, visit adama.com