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Control Phytophthora in CA Citrus this Spring

March 18, 2019
Phytopthora can reduce citrus root mass as displayed in the untreated root mass on the left.

Phytopthora can reduce citrus root mass as displayed in the untreated root mass on the left.

When it comes to disease management, the key to success is knowing how to properly identify diseases so you can diagnose early and begin treatment quickly. The University of California has up-to-date resources for citrus disease management, including these guides to identifying citrus diseases in fruit and in leaves and twigs.

One of the most prominent diseases this time of year after a wet spring is Phytophthora.

  • Phytophthora continues to be a damaging pathogen in CA citrus orchards. It attacks root systems, trunks, fruit and ultimately, entire trees. Tree health decline can occur rapidly within a year, especially under wet conditions.
  • The best option for control is to rotate fungicides with different modes of action. Syngenta suggests rotating Orondis® and Ridomil Gold® SL fungicides.
  • Now registered for use in CA citrus, Orondis fungicide offers an active ingredient, oxathiapiprolin, with a unique mode of action and no cross-resistance to other products. Orondis promotes improved root health and outstanding control of Phytophthora root rot by reducing the number of viable Phytophthora propagules in the soil. This leads to improved root mass, facilitates better water and nutrient use, improves root health, and ultimately increase yield and profit potential.
  • Ridomil Gold SL is a preventive fungicide that protects against root rot and increases feeder root growth to ensure better water and nutrient use efficiency through the entire tree. The active ingredient, mefenoxam, moves systemically upward in the citrus root system, providing uniform distribution. By inhibiting RNA synthesis of oomycete pathogens like Phytophthora, Ridomil Gold SL disrupts critical life processes, which leads to disease control.

Learn more about Orondis and Ridomil Gold SL fungicides.

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