A Growing Concern in Canola Farming

Experts in crop pathology are sounding the alarm over the rising trend of farmers applying fungicides as a precautionary measure in Australian canola crops. While it might seem like a simple way to safeguard against disease, this practice could have dire long-term consequences.

The Hidden Dangers of Repeated Fungicide Applications

According to Fran Lopez-Ruiz, the lead of the Australian Fungicide Resistance Extension Network (AFREN), the frequent use of the same fungicide could be paving the way for resistance among fungal pathogens. Sounds alarming, right? This is especially true when these applications offer no proven yield benefits.

Fungicide resistance is a concerning reality that could render certain fungicides ineffective, stripping farmers of valuable options for disease management and leading to a dangerous cycle of reliance on various other chemicals. This dependency raises the specter of multiple resistance scenarios, making it critical for farmers to rethink their fungicide strategies.

One Farm's Challenge Can Become a Regional Crisis

Fungi with resistance can spread spores rapidly, creating regional challenges from localized overuse. Dr. Lopez-Ruiz pointed to the example of net form net blotch (NFNB) in barley crops across South Australia, Western Australia, and Victoria as a case study of how one farm's practices can quickly escalate into a broader issue.

The Ugly Reality of Blackleg Resistance

Steve Marcroft from Marcroft Grains Pathology raises another crucial point—blackleg, a common canola disease, shows reduced sensitivity to several fungicide groups across multiple Australian states. There's increasing concern that this could lead to field failures, particularly in disease-friendly environments.

Additionally, mutations are appearing in fungi resistant to two other groups of registered fungicides, increasing the urgency for farmers to reconsider their approaches.

The Dangerous Allure of Overuse

Some growers have inquired about using unconventional tactics like applying double rates or off-label treatments to manage resistance issues. However, Marcroft emphasizes that such practices not only violate regulations but also contribute to escalating resistance levels. Stick to the label recommendations.

Tactical Applications Could Save the Day

Recent findings suggest that applying fungicides at the wrong growth stages, specifically during the four to eight-leaf stage, may exacerbate resistance issues. In fact, canola plants can endure a certain level of disease—up to 20 percent crown canker infection—without suffering yield losses, making early applications unnecessary.

A Call for Rethinking Fungicide Strategy

Dr. Marcroft advises growers to consult with agronomists and carefully weigh the risks and benefits of fungicide applications, as what appears to be an inexpensive safety measure could pose long-term risks to canola production. The message is clear: less can be more. Excessive fungicide use when disease pressure is low may lead to ineffective treatments when they’re genuinely needed.

Implementing Best Practices for Disease Management

Farmers are encouraged to adopt the AFREN Fungicide Resistance 5 principles for integrated disease management. This includes strategic planting distance from last season's stubble, timing sowing to mitigate risks, and rotating more resistant varieties. For further guidance, the AFREN website offers a wealth of information.

In sum, Australia’s canola industry is at a crossroads; sustainable practices today could safeguard yields tomorrow.