by LUIS RODRIGUEZ, UF/IFAS Polk Extension
& ALISSA HEVESH, UF/IFAS Highlands Extension
Citrus greening, or Huanglongbing (HLB), is a bacterial disease spread by a vector called the Asian citrus psyllid, which infects citrus trees and causes yellowing leaves, poor fruit development, and tree decline, leading eventually to the death of the tree. Citrus greening is a major challenge for Florida citrus growers, as it is one of the most destructive diseases affecting the citrus industry. The disease weakens trees, reduces fruit quality and yield, and increases production costs, placing significant financial and management pressure on farmers. Unfortunately, this disease has no cure, and the Asian citrus psyllid has already spread across the whole state. For this reason, growers must rely on integrated pest management (IPM) strategies to sustain productivity and slow the negative impacts of this disease within their groves.
Integrated Pest Management for Preventing and Managing Citrus Greening
Citrus growers can incorporate IPM to minimize the effects of citrus greening on their farms. IPM is a comprehensive, sustainable approach to managing pests that aims to reduce management costs, conserve energy, and minimize risks to people, animals, and the environment. IPM focuses on informed decisions through a combination of production practices, including accurately identifying pests on specific plants, regularly monitoring and scouting pest populations, and following established action thresholds to determine when control measures are necessary. In addition, IPM emphasizes preventing pest problems through cultural, biological, and mechanical strategies, and combining multiple methods of pest control techniques to achieve an effective control goal of a specific pest problem in the most efficient and economically feasible way.
IPM Methods for Managing Citrus Greening in Florida Groves
- Identification and Scouting: Scouting and identification are the first steps in any IPM program. While most groves in central and south Florida most likely have populations of psyllids within their farms, it is crucial to confirm their presence and the scale of infestation before making decisions and selecting pest control methods. Citrus trees have other pest threats besides psyllids, which can require different management strategies.
- Physical Barriers: Physical barriers, like Individual Protective Covers (IPCs) or Citrus Under Protective Screening (CUPS) systems, utilize mesh to prevent psyllids from accessing citrus trees and spreading infection. While they do present potential challenges such as cost and management, they are proven to prevent psyllid infestation and nearly eliminate HLB in the protected trees.
- Particle Films: Applying particle films like kaolin clay to citrus leaves can make it difficult for psyllids to recognize them as their host plants. Additional benefits have also been noted, such as shading the outer canopy of the trees, which can lower the leaf temperature, thus reducing water loss from trees.
- Trap Plants: Trap cropping near or around groves serves as an alternate host plant and can help attract psyllids away from citrus trees. Examples include orange jasmine (Murraya paniculata) and box orange (Severinia buxifolia). Cover crops are also being researched as a tool for increasing soil health, which can strengthen infected trees.
- Biological Control: Biological controls, which utilize natural enemies to fight off pests, have also been shown to manage psyllid populations. The Florida Department of Agriculture and Consumer Services (FDACS) releases millions of parasitic wasps of the species Tamarixia radiata each year. The female wasps lay eggs on psyllid nymphs, which eventually consume the psyllid’s body fluid and pupate in the empty psyllid casing. After metamorphosis, the adult wasps chew themselves out of the psyllid casing and fly off in search of other psyllids to attack. The small wasps do not have negative impacts on any other organisms and do not sting people.
- Chemical Control: Natural pesticides and products, including Neem oil, can play a role in managing psyllid populations, although they are more commonly used in residential locations and are not generally used in Florida’s commercial citrus settings. One of the goals of IPM is to minimize potential negative impacts on the environment as much as possible. That said, utilizing some level of chemical control will greatly increase the IPM program’s effectiveness. Systemic pesticides include soil-applied insecticides for non-bearing trees and foliar-applied insecticides for trees bearing fruit. Applying insecticides after practices that promote new growth, such as hedging, topping, and fertilizing, is especially important, as psyllids are attracted to new flush. Note that these products can negatively affect the natural enemies of other citrus insect pests, causing new pest problems to arise, though it is unlikely that they will be more harmful than psyllids and HLB.
- Cultural Control: Good grove management practices can also help with pest control. Healthy plants are less susceptible to pest problems. Cultural practices include protecting root health, managing nutrition/fertilization efficiently, utilizing best irrigation practices, removing dead trees and replacing them with new ones (resets), and taking good care of these resets.
Management Strategies Are Essential
Citrus greening remains a challenging disease threatening Florida’s citrus industry, making effective management strategies essential for farmers. Integrated Pest Management (IPM) offers a sustainable, efficient approach by combining practices such as monitoring, prevention, and control methods to reduce psyllid populations and minimize disease impacts. By adopting these practices, farmers can better protect their trees, maintain productivity, and improve long-term grove sustainability.
For more information about Citrus Greening, please read the following “Ask IFAS” publication: “2025–2026 Florida Citrus Production Guide: Asian Citrus Psyllid”
or visit the “Statewide Citrus Research and Extension: Particle Films”
or visit the “FDACS Asian Citrus Psyllid Biological Control website”
Luis Rodriguez is the Polk County Small Farms and Pesticide Education Extension Agent. You can reach him at [email protected] or 863-519-1049. Alissa Hevesh is the Agriculture and Natural Resources Agent in Highlands County. You can reach her at [email protected] or 863-402-6540.