Trunk-Injection Suggestions

Daniel CooperHLB Management


University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) associate professors Ute Albrecht, Ozgur Batuman and Megan Dewdney recently wrote Suggested Use Pattern of Injectable Antimicrobials for Huanglongbing (HLB) Management (April 2024). They emphasized that the document is not an official UF/IFAS recommendation but is based on the labels for antimicrobial products ReMedium and Rectify.

Some key suggestions in the document follow. 


The following injection application dates in Florida are “most desirable,” by variety:

  • March through May for early-season varieties such as Hamlin, Navel and Fallglo
  • March through June for mid-season varieties such as Murcott, Pineapple and Midsweet
  • March through August for late-season varieties such as Valencia
  • March through May for grapefruit

One month later for each variety (June for early-season, for example) is suggested as a “less desirable” injection time.

  • Do not apply during bloom.
  • Do not apply during leaf flushing.
  • Apply when leaves are fully expanded for efficient uptake and distribution.
  • Trees should be well-watered before and at the time of application.
  • Do not apply during drought conditions.
  • Leaf yellowing (phytotoxicity) may occur on the side of injection.
  • Only inject once the product is fully dissolved.
  • Only use freshly prepared solution.
  • Do not re-use injection sites.
  • The rootstock is the recommended location for injection, but scion injections are also effective.
  • Subsequent injections should be above or below the initial site by 2 inches and on the opposite side, or to the right or left by 2 to 3 inches.
  • Do not use any post-wounding treatments as these may interfere with wound healing.
  • Injection into the trunk can cause significant damage to the tree.
  • Trees with a trunk diameter of less than 2.5 inches are prone to more damage.
  • Minimizing the hole size will minimize tree damage.

Additional information in the document addresses pre-harvest and re-entry intervals, dose per tree by trunk diameter, personal protective equipment and more.

Source: UF/IFAS

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