Bipolaris is a fungal disease that causes irregularly shaped brownish-green to black lesions to appear on the surface of the leaf blade.  Leaves severely infected by Bipolaris will begin to die back turning tan to dark brown. Bipolaris is most commonly a disease of turf growing in stressful conditions with a poorly draining surface.
What are the Symptoms of Bipolaris?
Symptoms of Bipolaris include:
Irregularly shaped brownish green to black lesions may appear.Â
Severely infected leaves begin to die back turning tan to dark brown.Â
Irregularly shaped patches of infected foliage may range from 5cm to 1m in size.
Chlorosis may occur in infected foliage before the leaf turns brown.
Extensive crown and root rot may occur in severe infections.
Plants may lose vigour, becoming weak and flaccid.
Bipolaris is caused by the fungi Bipolaris spp. and is most commonly a fungal disease of turf growing in stressful conditions with a poorly draining surface.
When does Bipolaris Occur?
In general, the conditions favouring Biplaris are:
Cool, wet periods from autumn to spring where foliar blight and lesions occur
Warm humid weather throughout summer where crown and root rot may occur
More than 10 hours a day of leaf wetness for several consecutive days.
Poor air movement (high humidity in the micro-climate).
Excessive nitrogen fertiliser.
Excessive thatch and loose leaf clippings provide a source of food for the fungus.
Any stress situation such as drought, herbicide injury or heavy traffic can increase the severity of the disease.
What Turfgrasses are Especially Susceptible to Bipolaris?Â
Warm season turfgrasses
What can I do to manage Bipolaris?
Management practices that can help manage or reduce instances of Bipolaris include:
Maintain healthy turf through proper fertilisation. In particular, paying particular attention to potassium and nitrogen levels.
Irrigate infrequently and deeply. Avoid late afternoon or evening irrigations.
Do not allow the turf to become extremely dry during warm weather.
Increase air movement and improve drainage
Avoid herbicide applications during critical periods of disease activity.
Disperse traffic in high-traffic areas.
Mow turf at a height recommended for the turfgrass species.
For chemical solutions and treatments for Bipolaris, please see the recommended products below.
Daconil Weather Stik is a contact fungicide that can be used in preventative programs. It can be used as an early curative after the first signs of disease become evident.
Headway Maxx combines the strength, longevity and broad spectrum of Heritage Maxx with the speed and early curative action of Banner Maxx in an unbeatable combination.
Dedicate turf fungicide contains two active ingredients with two different modes of action, providing curative and preventative control. It has a contact and systemic action in turf which provides broad spectrum control.
Interface with Stressgard Formulation Technology offers the new standard in turf protection and is Bayer’s most powerful turf fungicide to-date. It manages disease stress leading to improved turf quality and playability.
Chloronil Pro Fungicide is a broad spectrum, contact or protectant fungicide for the control of a range of diseases fruit, vegetables and turf. It is registered for the control of Brown Patch, Dollar Spot and Grey Leaf Spot in all recreational turf situations. It is also registered for the control of Botrytis, Grey Mould, Rust and Septoria and Alternaria Leaf Blight for application on ornamental plants.
Vantage fungicide is a broad spectrum, systemic fungicide containing 95 g/L of the active constituent Azoxystrobin, a trusted chemistry for Australian turf professionals.
