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About Prosaro

What is Prosaro® 420 SC

Prosaro 420 SC is a protective and curative fungicide that offers a very broad spectrum of disease control in all key cereal crops (wheat, barley, oats and triticale) as well as in canola where it controls the two key diseases blackleg and sclerotinia.

Prosaro 420 SC is designed to provide effective and long lasting control combined with excellent curative (kick-back) activity. The combination of prothioconazole with tebuconazole leads to an improved control over the straight products due to the supplementary effect of combining a systemic molecule with excellent residual activity (long lasting effect) and a fungicide, that exhibits distinct curative properties (fast acting effect). Both molecules support and complement one another in their effects. Tebuconazole is the compound with a pronounced initial effect, whereas prothioconazole is responsible for the long duration of activity.

Prosaro 420 SC offers flexible application timing, enabling targeted application to effectively manage specific diseases at the most appropriate development stage. 



Product information

Product Type Fungicide
Mode of Action DMI (Inhibitor of demethylation)
Active Ingredient Prothioconazole 210 g/L Tebuconazole 210 g/L
Formulation Type Suspension concentrate
Grouping 3
Chemical Group Triazole
Pack Size 10 L



Assessing the risk of blackleg in your canola

Download the latest GRDC Blackleg Management facesheet to further quantify your blackleg


Blackleg (Leptosphaeria maculans) disease cycle

Blackleg epidemics are primarily initiated by airborne ascospores originating from matured pseudothecia (fruiting bodies) of the fungus on previous years infected stubble and crop residues. Higher temperatures and lower moisture conditions during summer and autumn, favour the maturity of pseudothecia. Once matured, pseudothecia are triggered to release ascospores by rainfall or even heavy dews and high humidity.

Early seedling infections are the most critical as they are most likely to produce severe stem cankers and yield loss. The two most important blackleg risk factors are the proximity to infected canola crop residue and the timing of the first major ascospore release from old canola crop residues that synchronise with the seedling susceptible stage of this year’s crop. 




Canola Growth Stages


For blackleg control, it is recommended to apply Prosaro at 4 to 6 leaf stage (stage 1). In situations of high blackleg risk or where an effective seed or in-furrow treatment has not been used, a follow up application of Prosaro may be required at green bud stage (stage 3).


Prosaro should not take the place of Jockey Stayer or flutriafol in-furrow but be used in combination with one or both for the best economic return. MS and MS-MR blackleg disease-rated canola, blackleg disease-rated canola varieties are most likely to return an economic response. However, canola varieties with higher blackleg resistance levels that have been grown continually in a region, and where genetic resistance has broken down can also show an economic response.

An early (4 to 6 leaf) foliar spray application provides more consistent disease control and better protection of crop yield than the later (green bud) timing. Furthermore the earlier (4 to 6 leaf) timing sprays with Prosaro have excellent compatibility with a range of herbicides and foliar nutrients.

The higher Prosaro 450 mL/ha rate is generally more effective than 375 mL/ha, particularly under high disease pressure. When blackleg infection is high an application of two Prosaro sprays will improve disease control and maintain yield potential.

Canola plants that have been sprayed with Prosaro will often appear greener and retain older leaves for longer.


Risk factors for a sclerotinia outbreak

Current management options for sclerotinia are limited to crop rotations, cultural methods and the use of fungicides. In regions prone to sclerotinia infection it is vitally important to have a proactive program for sclerotinia control in canola.

The following conditions are risk factors for a sclerotinia outbreak in canola:

• Wet conditions for at least 10 days with good soil moisture in mid to late winter and temperatures of 11- 15°C will germinate sclerotia and trigger spore release.
• The crop canopy remaining wet for extended periods during flowering will favour petal infection.
• Extended wet periods following petal drop and leaf infection will encourage infection of the leaves and promote subsequent stem infection.
• Stem lesion development is favoured by humid/wet conditions and mild (20 - 25°C) temperatures.

Download the latest GRDC Sclerotinia Management factsheet to further quantify your sclerotinia risk.


Sclerotinia management checklist

• Broadleaf crops and weeds are susceptible to sclerotinia. However, cereals are not.
• Ensure farmer-retained canola seed is free of sclerotinia contamination. Sclerotia are the hard black resting bodies of sclerotinia which resemble rat droppings and carry sclerotinia over to subsequent seasons.
• Prosaro should be applied between 20% and 50% (full bloom) flowering where there is a moderate or high risk of sclerotinia. For best results apply at 20% to 30% flowering prior to disease development.
• Use the 450 mL/ha Prosaro rate under higher disease risk. A second application may be required in high pressure situations. • When spraying for sclerotinia, good coverage throughout the entire canopy is essential. Use higher water rates (i.e. 100 L/ha for ground application and 30 L/ha for aerial application) to improve spray coverage.
• Prosaro is compatible with a range of insecticides and herbicides. To find out more, contact your local reseller agronomist or Bayer representative.

Don’t risk reduced yields! Use Prosaro, the third generation triazole combination formulation that provides exceptional disease control that can seriously boost your bottom line.


See the results for yourself



Key observations from the 2011- 2013 trial work

• Across 25 trials over three seasons a mean yield increase of 20% over the untreated was recorded.
• The range of responses highlights the importance of spray timing, disease levels and weather conditions. Higher yield increases were recorded when conducive conditions coincided with high incidence of infection and severity with application of Prosaro made prior to significant infection in the crop.
• A maximum of two applications of Prosaro per crop and season is allowed. The number of sprays of Prosaro that may be applied per crop includes any applications made earlier in the season for blackleg control, a two-spray strategy will differ in the timings to protect the crop’s yield potential.

*Economic return from an average of 1.9 t/ha yield from 100% based on canola at $500/tonne and an average application cost of $6/ha.
Jockey® Stayer® or Intake® yield average (applied alone): 1.90 t/ha
^Mean yield increase from Prosaro 375 mL/ha over untreated: 20% (25 trials)
Trial ID: Data generated from commercial applications


Canola Growth Stages – Sclerotinia

To achieve the best control of sclerotinia infection and protect the crops’ yield potential, it is recommended that Prosaro is applied before the disease symptoms become visible. Prosaro applications should be made between 20 - 50% flowering. Applying Prosaro too early can reduce the economic benefits from the fungicide application by not protecting the most critical stages of canopy development and petal fall.