California almond growers continue to face increasing challenges with fungicide resistance, a persistent issue affecting the efficacy of disease management practices. Experts, including Katie Driver, Technical Services Manager for UPL in Northern California, emphasize the importance of rotation and responsible stewardship to combat resistance.
California almond growers continue to face increasing challenges with fungicide resistance, a persistent issue affecting the efficacy of disease management practices. Experts, including Katie Driver, Technical Services Manager for UPL in Northern California, emphasize the importance of rotation and responsible stewardship to combat resistance.
According to Driver, resistance has developed over several years due to repeated use of the same fungicide groups. She notes that major almond diseases, such as monolinea, Alternaria, scab, anthracnose, and shot hole, have all shown signs of resistance to various fungicide groups, particularly those categorized under FRAC (Fungicide Resistance Action Committee) codes. This repeated use has placed selection pressure on fungal pathogens, leading to the presence of resistant strains that cannot be reversed.
To mitigate this issue, Driver stresses the importance of rotating fungicide groups. Modern fungicide labels now prominently display their FRAC codes, making it easier for growers to identify and switch to alternative chemistries. Additionally, multi-site fungicides, which are less prone to resistance, can be incorporated into treatment programs. Beyond chemical solutions, cultural practices such as proper irrigation management, pruning for airflow, and orchard sanitation can play a crucial role in disease prevention.
Growers should remain vigilant and monitor their fields closely. A key indicator of resistance is when a previously effective fungicide no longer controls the targeted disease. If a fungicide fails to produce results from one season to the next, it may be necessary to explore alternative or newly developed chemistries.
To aid in this effort, UPL has introduced Axios 20SC fungicide, which features a new active ingredient, quinoprol, classified under FRAC group 52. This marks a breakthrough in fungicide options, as it is the only active ingredient in its group, eliminating concerns of cross-resistance with existing treatments. Driver highlights that Axios can reset the clock for growers battling resistant fungal strains and prevent further resistance development.
In addition to its novel mode of action, Axios 20SC is an EPA-designated reduced-risk pesticide, making it environmentally friendly. It also has a low use rate of five fluid ounces per acre, which adds to its convenience and ease of application.
For more information on fungicide resistance management or details about Axios 20SC, growers can visit UPL’s website at upl-ltd.com/us or consult their local pest control advisors (PCAs) and UPL representatives.
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