Dr. Lauren Diepenbrock's Laboratory

Research Projects

Asian Citrus Psyllid Management

Asian citrus psyllid (ACP) is an invasive species that has been in Florida since the late 1990s. No only is the insect itself a pest to citrus trees, it is also a vector for Candidatus Liberibacter asiaticus, the bacteria linked to citrus greening (Huanglongbing/HLB). This disease is a threat to the worldwide production of citrus. In Florida, much research has gone into both short and long term management options for both the pest insect and the pathogen. Despite these efforts, the pest still remains a major management challenge and there is still a lot of research to be done both in terms of the ecology of the pest-pathogen complex and ready to use management tools.

Our lab is currently involved in several pojects pertaining directly to ACP and HLB:

Non-target Impacts of ACP Management

Citrus greening has an enormous economic impact on citrus production. As such, efforts to reduce the population of vectors (ACP) and/or minimize their movement and the corresponding spread of the pathogen are important for managing the disease. To slow the initial spread of disease, area-wide management in the form of coordinated insecticide-based management was performed throughout much of the state of Florida (CHMA program). Unfortunately, there were challenges to the full implementation of this program and it has since dissolved. But groves still require active management, and at present, insecticides are the primary tool for vector management. Exposure to these materials can also have impacts on organisms other than the intended target(s). 

Projects looking at non-target impacts of ACP management:

  • Documenting non-ACP pest arthropod populations under relaxed new management paradigms- Similar to CLM, many scales and whiteflies associated with citrus have largely been under control by a combination of generalist predators and specialist parasitoids. During intense ACP management, these pests were also kept at a minimum likely from exposure to broad-spectrum insecticide applications. Recently, there has been a shift in many overall grove management programs to focus on plant health and reduce insecticide reliance. With this shift, we anticipate seeing populations of several pests like scales and whitefly become more apparent and potentially problematic. What we don't know is if the predators, including parasitoids, are still present and sufficiently abundant to control these pests. 

Habitat enhancement for beneficial insects

Beneficial insects, particularly predators/parasitoids, have a long history of being integral parts of pest management in citrus. The intense management meeded to reduce ACP impacts has reduced the visible abundance of these organisms which used to be easily spotted in Florida citrus groves. Researchers across the state are interested in developing management options that enable beneficial arthropods (insects, mites, and spiders) to re-establish and thrive once again.

Projects for promotion of beneficial insects:

  • Cover crop for soil and tree health improvement (ACP management is an add-on to their main goals)-- Lead PI: Dr. Sarah Strauss
  • Non-crop habitat for beneficial arthropods (project under development)

Invasive arthropods and their management

Citrus is a global crop, it is grown in over 100 countries and imported/exported throughout the world. As such, movement of pests and diseases is a major concern. Like all traded items, movement of citrus fruit into and out of countries is heavily regulated to minimize the potential for pests to move on these shipments. Sometimes, however, pests and diseases still manage to be moved into new areas where they can become problematic. Approximately two decades ago, this was the case for the arrival of Asian citrus psyllid, the primary vector of CLas (see above). In 2019, Florida growers have been challenged by the finding of a mealybug, Nipaecoccus viridis, which is known to be problematic in citrus production in other parts of the world. Our lab is working with our state regulatory authority, the Florida Department of Agriculture and Consumer Services- Division of Plant Industry, and industry partners to help our growers detect and manage this pest.

  • Biology and ecology of Nipaecoccus viridis-- Ph.D. student project
  • Determining breadth of potential predators of Nipaecoccus viridis-- MS student project
  • Field management of Nipaecoccus viridis-- in progress