Australia
September 24, 2019
The pathogens that cause downy mildew vary from crop to crop but ORONDIS FLEXI® offers excellent control and resistance management.
The individual fungal species that cause downy mildew in various vegetable crops type are distinctly different species - as a new product ORONDIS FLEXI® offers excellent control over downy mildew while being being a resistance management tool.
The pathogen Pseudoperonospora cubensis, which causes downy mildew in cucurbits, is accepted by CropLife Australia as showing a high risk of developing resistance to fungicides.
Bremia lactucae causes downy mildew in lettuce and Peronospora spp. is responsible for downy infections in various brassica crops. Both are noted by CropLife Australia as showing a medium risk of developing resistance to fungicides.
“The key message for growers is to have a management plan in place for the coming season that includes a strategy for long-term, effective fungicide use,” Syngenta Technical Services Lead Shaun Hood said.
New downy mildew fungicide
To broaden the control options, Syngenta has just released ORONDIS® FLEXI.
>>Click here for the full crop list and application rates
ORONDIS FLEXI contains two active ingredients with two different modes of action (Group 11 and 49 fungicides) delivering a unique fungicide resistance management tool.
Very strong on downy mildew, ORONDIS FLEXI also has activity on other important diseases in vegetable crops including white rot, alternaria leaf spot, white blister, sclerotinia rot, powdery mildew and gummy stem blight.
“This product exhibits translaminar movement into leaves protecting both the upper and lower leaf surfaces,” Dr Hood said.
“The active ingredients move in the xylem towards the growing tips, protecting both existing and expanding leaves. It also has excellent spray retention on the plant surface and is rainfast within one hour of application.”
A suspension concentrate, ORONDIS FLEXI mixes readily with water and is applied as a foliar spray. It is compatible with a broad range of insecticides that are commonly used in the registered crops.
Stack the odds in your favour
Growers are reminded that downy mildew spores are spread readily by wind. They also survive in the soil and on crop residues.
“Cultural practices, such as; the establishment of a crop-free period to reduce susceptibility; crop rotation; and the destruction of crop and weed hosts, are great control measures,” Dr Hood said.
“Incorporation of infected crop residues into the soil immediately after harvesting may also help to slow the spread of disease.
“Other agronomic practices such as optimal plant density and wider row spacings allow better air flow and spray penetration assisting with disease control.”
Syngenta also urged growers to plant resistant varieties wherever good selections exist.
“Even with tolerant varieties, fungicides are an important part of the overall management plan because downy mildew is highly variable in Australia,” Dr Hood said.
“This disease is notorious for its ability to adapt and overcome resistant genes in resistant cultivars.”
A disease management program that includes rotation and/or tank mixing with fungicides with a different mode of action is essential to reduce the risk of fungicide resistance.
In certain crops the use of ORONDIS FLEXI is subject to specific resistance management strategies. Before using the product growers should refer to the CropLife Australia website www.croplife.org.au, in conjunction with the product label for details.
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