A UF/IFAS Tip of the Week shares recommendations for combating phytophthora during the fall root flush.

The fall root flush is underway, and it will continue through November and December. It’s the time when citrus roots store carbohydrate reserves and grows new roots that will deliver the water and nutrient uptake for the spring leaf flush and flowering. According to a UF/IFAS Tip of the Week and accompanying Citrus Industry article, phytophthora is attracted to these new roots, so it is time to ensure you’re combating the phytophthora pathogens that have been multiplying during the rainy season. See the recommendations below.

The Fall Root Flush and Phytophthora

The recommendations for combating phytophthora during the fall root flush include:

  • “If you haven’t been monitoring your phytophthora populations in your groves, it is time to take soil samples for threshold-based management decisions.”
  • “Products with higher efficacy than phosphite are recommended for protecting the fall root flush.”
  • “If you didn’t apply phosphite in late July or August or have a problem developing, copper sprays can prevent additional spread to protect the rest of the crop.”
  • “If you have high soil inoculum, a copper or Revus spray could help protect the fruit as phosphite efficacy drops.”
  • “If you are concerned about a possible extended rainy season, you may want to plan a second phosphite application 60 days after the July application.”
  • “While grapefruit is also susceptible to brown rot, it should already be protected by a copper-based canker management program if it is for fresh market.”

Griffin Fertilizer is committed to helping both growers and ranchers make sound agronomic and economic decisions in order to maximize the health of their grove and pasture. As a full-service custom dry & liquid fertilizer blender and crop protection product distributor, we will continue our mission to further advance Florida agriculture. For questions or concerns about your farm or pasture, contact us and one of our team will be in touch.