Herbicides and Huanglongbing: Assessing Indaziflam Use in Florida’s Citrus Groves
Posted August 2025
Researchers: Ramdas Kanissery, Nirmal Timilisina, Ozgur Batuman
Contact: Ramdas Kanissery, UF/IFAS SWFREC rkanissery@ufl.edu
Summary:
To address the challenges of huanglongbing (HLB), Florida citrus growers have implemented enhanced nutrition and irrigation strategies to support tree health and sustain yields. While these practices are beneficial, they also encourage weed growth, leading to increased reliance on herbicides. This has raised concerns about the potential non-target effects of certain herbicides on HLB-affected trees, which are already prone to reduced root growth and higher rates of pre-harvest fruit drop. This study investigated the potential impacts of indaziflam, a widely used pre-emergence herbicide and the active ingredient in Alion®, on root growth, HLB disease severity, and fruit detachment force in two key juice citrus cultivars, ‘Hamlin’ and ‘Valencia’. The research was conducted in two commercial groves in southwest Florida and included three application rates of indaziflam (low, medium, and high), all within the approved use range for citrus. These treatments were compared to herbicide untreated and weed-free controls, with all plots managed under standard grower practices. Results showed that indaziflam did not significantly affect root growth, disease severity, or fruit detachment force at either location. These findings suggest that, under the conditions tested, indaziflam does not negatively impact root development or worsen HLB-related symptoms. However, given the herbicide’s widespread use in Florida citrus production, continued long-term research is required to better understand its potential non-target effects in citrus groves.
Take Home Message:
- Indaziflam showed no harmful effects on root growth or fruit detachment in HLB-affected citrus.
- No increase in HLB severity was observed with indaziflam use.
- Ongoing research is important to confirm the long-term safety of repeated indaziflam use.
