This project from the Citrus Research and Education Center (CREC) will survey citrus groves across the state to assess Hurricane Ian’s impact and how quickly the trees recover from it. We hope the results of these surveys will help you better understand the medium-term impacts of hurricanes based on windspeeds. Other goals for the project include equipping you with knowledge to develop plantings that are more resilient against storms. We hope this information can help with recovery, both now and in the future. Overall, we hope this knowledge will be applicable and useful for growers to protect their groves from storm damage. To do this we will be surveying your groves monthly to measure over time the impact of Hurricane Ian.
A hurricane damaged tree and a tree involved in the study.
This is the first update that will summarize the results of the surveys and share their potential application for grower practices. Results will eventually be published in Citrus Industry Magazine as well. An EDIS document for grower use will also be published in late 2023 outlining how to make plantings more resilient, recover from wind damage, and predict the severity of the damage on their groves based on the storm.
For questions or more information, please contact project leader Christopher Vincent at firstname.lastname@example.org.
We are excited to share our results with you over the next year. Please share this blog with anyone who also might find this information pertinent!
In our study kaolin particle films helped manage pests, and also improved tree growth. Kaolin particle films are a type of mineral that can be sprayed on plants to create a protective layer. Asian citrus psyllids, the pest that transmits citrus greening disease (HLB), are attracted to the natural color of leaves and the particle films cover this. White and red colored particle films were used in this study. Trees with white and red dye had a greater growth rate of trunk girth than controls, regardless of infection. This study found that particle films helped reduce the number of psyllids on leaves, as well as increased tree growth under HLB pressure.
HLB is the current largest threat to the Florida citrus industry; citrus production has declined, and citrus trees are nearly all infected. HLB stunts tree growth and limits yield, especially if infection occurs when the trees are still small. We studied for three years whether kaolin particle films on newly planted trees could help manage psyllids. We also tracked tree growth response to particle films and HLB.
HLB reduces the growth rate of trees and negatively affects fruit yield and other quality characteristics. HLB cannot be cured once trees are infected so pest control is the usual course of action when it comes to preventing infection. HLB is spread when adult psyllids carry the bacterium from infected trees to uninfected trees. Kaolin particle films are a potential alternative to insecticides as a way to manage psyllids and the reduction in tree growth caused by HLB.
Increased growth in treated trees happened in spite of HLB infection. The positive impact of particle films on growth is likely due to shading, reducing photoinhibition, and light redistribution to lower canopy layers. Kaolin treatments increased growth enough that they made up for the loss in growth from infection. This is promising because it helps relieve pest pressure, while increasing growth of HLB affected trees.
Fasih Khalid came to CREC from Pakistan for a six-month program to work as a horticulturist focused on stress physiology. He also wanted to learn about physiological techniques and how to use different instruments. In Pakistan, he spent time working on abiotic stresses like water deficits and salinity. In our lab, he worked on experiments dealing with sap flow and hydraulic conductance. He said with the results the lab can determine whether “the sap flow movement is OK in relation to the regular irrigation.” Because of rising prevalence of water deficit problems in the world, it is important to see how irrigation levels in plants can be adjusted to save water and lead to more efficient water practices in the future.
Fasih loves research and learning. After his Master’s he spent about a month working in a farmer’s co-op in Pakistan, which he didn’t enjoy. As soon as an opportunity presented itself, he entered his PhD. He had done research on lychee in his Master’s and had published it, so he decided to go back to school and into the research field. After a couple of months in his PhD, he decided “…there is nothing in the world for me except research. I have to be researching.” He initially was interested in horticulture after going through his required two years of studying it in Pakistan. He thought he wanted to work in floriculture and landscaping but ultimately found pomology to be the most engaging because there are many different opportunities in that field. Plus, “The good thing of fruit is you can research or if you don’t want to research you can eat.”
During his time at CREC, he was also able to participate in several competitions, most of which were academic, though one was a t-shirt design contest for CREC, which he won! The academic competitions allowed Fasih to share the work he did at CREC, as well as help him improve his English. He liked to share that his work is important because it helps growers understand how to adapt to a world with climate change. He believes it is important for all people, not just growers, to care about changing water conditions and how this affects plants because “…we have to save water for the world and for the plants, for the next [plants].” If growers are unable to find solutions for their plants in water scarce conditions, this will cause further problems for the world as demand for fresh water reserves increases, eventually affecting our food supply, which would affect us all. He wants to take the things he’s learned during his time here back to Pakistan. His two big takeaways were time efficiency and the benefits of using hydraulics instrumentation for research. He hopes to apply these lessons as he continues horticulture research in the future.
Trees provide shade, but have you ever considered trees themselves needing shade? Our lab is seeking to answer this question. Anirban Guha, who is leading this effort in our lab, was able to sit down with me and answer some questions about the experiment. He joined the lab in April 2019 as a post-doctoral scholar. The experiment is attempting to determine how the trees respond to different light conditions over a period of two to three years with the use of shade nets to manipulate the environmental conditions. The lab records daily, weekly, and monthly results, and will record the yearly results when the time comes. We already know that citrus responds better in partial shade conditions, which improve yield and yield quality and photosynthesis and water status. We think that full sun has an especially bad effect on HLB trees. Anirban explained that the infected plants often cannot take in the full force of Florida sunlight; it provides them with more energy than they have the capacity to process. HLB also stunts root growth, which becomes even more of a problem when high light conditions demand more water and nitrogen than can be taken up by the roots.
The lab is testing whether shading the trees allows them to conserve more energy and require less water and nitrogen, which would help balance their functioning with the disease. Ultimately, the goal is to “[develop an] agricultural system in a way that could modify the environmental cues, and that can lead to better fitness of the plant to help sustain yield and maintain better physical performance.”
The main recipients of this experiment are scientists and citrus growers; Anirban thinks these two groups believe they have different reasons for caring about the results, but he believes their goals are actually similar and the knowledge they seek is complementary. Whether results are sought for economic reasons or a research quest, the ultimate goal is to see the trees become healthier and create more fruit yield—something both the scientific and agricultural communities can agree upon.
Anirban takes this collaborative approach in his work life as well. The physiology lab collaborates with other CREC labs to study and test infected trees. Their results often work together to create healthier trees. For example, the entomology lab provides information on how insects spread HLB. He desires for more scientists of different disciplines to work together to achieve “functional collaborative research,” which can help the scientific community locally and worldwide. Along with scientists working together to achieve more, he also wants his research to be holistic. He wanted to study trees not just at a cellular level, but “from leaf to whole plant.” After completing his PhD in India, he found the majority of opportunities available there were for study at the cellular level. Anirban was interested in more variety and didn’t want to do what everyone else was doing. He also saw this gap in research as something he could potentially fill back home one day. He believes the study of the whole tree is important because problems tend to be linked to one another and can be better understood when a whole plant approach is taken. He enjoys his work but told me with a good-natured smile that he is not at all attached to the state of Florida and would like to return to India one day.