Florida produced 244 million boxes of oranges in 2003–2004. The 2023–2024 crop was under 17 million boxes. The single largest cause is Huanglongbing, also called citrus greening or HLB — a bacterial disease (Candidatus Liberibacter asiaticus) vectored by the Asian citrus psyllid (Diaphorina citri). It arrived in Florida in 2005 and is now present in all 67 counties.
If you have a citrus tree in your Florida yard, it is statistically very likely already infected. This guide is the honest version of what the disease is, what living with it looks like, and what (limited) tools homeowners actually have.
How to recognize HLB
The textbook symptom is asymmetric chlorotic mottling — yellowing of the leaf that does not mirror across the midrib. This distinguishes it from nutrient deficiency, which is almost always symmetric. Other indicators:
- Lopsided, small, hard fruit that stays green at the stem end (the name 'greening' comes from this).
- Bitter, salty fruit that drops prematurely.
- Twig dieback starting at the canopy top.
- Vein corking and yellowing on individual branches before the whole tree shows symptoms.
Definitive diagnosis requires PCR testing of leaf tissue at a state lab (UF/IFAS offers this through county extension offices). Symptoms can mimic zinc, manganese, and iron deficiency, and many homeowners spend years fertilizing a tree that is actually infected.
What is happening inside the tree
The bacterium colonizes the phloem — the vascular tissue that moves sugars from leaves to roots and developing fruit. Phloem plugs, sugars accumulate in the leaves (which causes the chlorosis), the root system starves, and the tree progressively starves itself even with normal soil conditions. Death typically occurs within 5–8 years of infection in unmanaged backyard trees, faster in young trees and slower in mature, well-established ones.
The honest options
Option 1: Aggressive nutrition therapy
Enhanced foliar nutrition — particularly micronutrients (Mn, Zn, B, Mg) and controlled-release nitrogen — can extend the productive life of an infected tree by years. UF/IFAS recommends quarterly foliar sprays with a complete micronutrient package and biannual soil applications. This does not cure HLB; it keeps the tree producing in spite of it.
Option 2: Oxytetracycline trunk injection
In 2023 the EPA approved oxytetracycline (OTC) trunk injection for HLB management. Field trials show meaningful reduction in bacterial titer and improvement in fruit quality for 1–2 years per injection. Cost runs roughly $40–80 per tree per treatment, applied annually. It is not a cure, and resistance management is a real concern, but for a high-value specimen tree it is the most effective tool currently available.
Option 3: Psyllid control
Controlling the vector (the Asian citrus psyllid) slows the spread to uninfected trees and the rate of re-infection. Imidacloprid soil drench in early spring, followed by foliar horticultural oil sprays through the warm months, is the standard residential protocol. Note that imidacloprid is restricted near pollinator-attractive plants and you should not apply it during citrus bloom.
Option 4: Replace with tolerant cultivars
No commercial citrus is resistant, but some are tolerant — meaning they can be infected and still produce. Sugar Belle mandarin, US-1279 grapefruit, and the Bingo mandarin are showing the strongest tolerance in trials. If you are planting new, plant tolerant; do not plant Hamlin or Valencia and expect 1990s outcomes.
What does not work
- Removing infected branches alone — HLB is systemic; pruning does not eliminate the bacterium.
- Copper sprays — effective for citrus canker, not for HLB.
- Standard balanced 8-8-8 fertilizer — does not provide the micronutrient profile an infected tree needs.
- Companion planting (guava, curry leaf, etc.) — popular online, no peer-reviewed evidence of effect on HLB.
- Removing the tree to 'save' nearby trees — by the time you see symptoms, every citrus on the block is almost certainly already infected. Removal does not protect neighbors.
Should you keep the tree?
Honest answer: for most backyard owners, yes, with realistic expectations. An infected, well-fertilized mature citrus tree in a Florida yard can produce edible fruit for another 5–10 years. The fruit will be smaller, less sweet, and yields will decline year over year. If the tree is structurally healthy and you value it, manage it.
Remove the tree if: it is producing only unusable fruit, it is in steep decline, or it sits adjacent to a commercial grove and you are asked to remove it as part of an areawide management program (rare in residential areas now).
The future
Multiple HLB-resistant transgenic lines are in field trial. CRISPR-edited citrus carrying resistance from spinach defensin genes has shown durable resistance in greenhouse trials. Commercial release is years away. In the meantime, the productive Florida dooryard citrus tree is a managed tree, not a planted-and-forgotten one.