Protecting single site chemistry in fungicide programs is essential in both ensuring good efficacy and preventing resistance. UPL are a lead manufacturer and developer of multisite actives, and with the loss of chlorothalonil (CTL), alternative options in crop protection strategies will need to be adopted this coming spring.

There are a range of multisite products and actives available which can be utilised in different ways to protect our most powerful chemistry and build on disease control strategies. Protectants and elicitors each have a valuable role to play; growers should consider disease pressure, seasonal difference, and varieties which all have an influence on which tool to pick up from the multisite toolbox..

ALTERNATIVE PROTECTANTS

Sulphur: inorganic fungicide with multi-site contact action (FRAC code M02).

UPLs new liquid sulphur product, THIOPRON® is a registered fungicide with a label recommendation for control of mildew, but with efficacy against septoria and has some evidence of efficacy against rusts. THIOPRON® can be applied from T1 as an alternative to CTL.

Historically sulphur was a powdery product consisting of various particle sizes, most of which end up in the plant as a micronutrient. The new liquid formulation from UPL really brings the active to life, with highly consistent and optimally sized particles for even distribution on the leaf. The liquid formulation also contains a sticking agent that improves binding to leaf surfaces. The sulphur reacts on the leaf surface to produce hydrogen sulphide gas. Toxic to pathogens such as septoria, the gas works as an antisporulant, proving very effective in early situations.

Mancozeb: dithiocarbamate fungicide with multi-site contact action (FRAC code M03).

As a highly cost-effective treatment, mancozeb has long been available for use in wheat and is one of the most similar alternatives to CTL. UNIZEB GOLD® is a liquid formulation of mancozeb and its label on wheat allows use from GS30 onwards, to control septoria. Mancozeb can be applied later than other multisite options and can subsequently be used as part of a T3 fungicide programme to control fusarium ear blight, whilst also providing some additional activity against yellow rust and brown rust. Compared to the alternative protectants such as folpet, mancozeb has the additional benefit of providing nutrition, as the active is a complex containing 20% Manganese and 2.5% Zinc.

ELICITORS minarin: polysaccharide fungicide with host plant defence induction action (FRAC code: P04).

Laminarin: polysaccharide fungicide with host plant defence induction action (FRAC code: P04).

Septoria control can be readily attained by triggering plant defences to undermine the disease. The novel active laminarin, contained in new product IODUS®, is a biological fungicide which stimulates a systemic response to disease. Working by triggering the plants immune defence in advance of infection, IODUS® is best applied at T0 - prior to the main fungicide timings. The systemic nature of this immune response means T1 and T2 fungicide timings will be supported from the earlier laminarin application. Tested at T0 in over 15 trials in 2019, yield responses thanks to this defence boost, averaged at more than 4% from a single application. IODUS® also has a label recommendation for reduction of powdery mildew, and there is some evidence of laminarin having efficacy against rusts.

Don Pendergrast, UPLs Head of Technical Services has conducted dozens of field scale trials of these new technologies over the past few years. We are seeing these two innovative products with their new modes of action improve efficacy against foliar disease and improve yield outcomes when used in commercial programs with other modes of action such as triazoles or SDHIs. Whats very exciting is that both actives are zero residue so can help growers to build low residue programmes that enhance IPM in cereal programs without compromising on efficacy.