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ARS Home » Office of International Research Engagement and Cooperation » OBCL Research Highlights » March 2023 » Letter from the EBCL Director

Letter from the EBCL Director:
A Bright Future for Classical Biological Control and International Collaborations

By Dr. Robert G Shatters, Jr., Director, USDA, ARS European Biological Control Laboratory (EBCL) 

Robert Shatters
Robert Shatters. (Photo courtesy of Robert Shatters)

Montpellier, France, April 6, 2023. Hello from Montpellier, France. My name is Robert (Bob) Shatters, and I am the Director of the USDA, ARS, EuropeanBiological Control Laboratories (EBCL) in Montpellier and Thessaloniki, Greece: a 2 to 4 year rotating duty station for U.S.-based ARS scientist. I have been here 6 months now and have had the great honor of getting to know the EBCL staff and the excellent Classical Biological Control (CBC) work that they are doing. The stories in this newsletter are a testament to the high-quality work done by all the Overseas Biological Control Laboratories (OBCLs).  As the EBCL Director, it is my duty to organize the OBCL Newsletter, and I felt it important to introduce myself and my professional goals. I come from the USDA, ARS, U. S. Horticultural Research Laboratory in Fort Pierce, FL where for 15 years I have worked to find solutions to citrus greening disease (a.k.a., HLB for Huanglongbing disease), a disease that has resulted in a greater than 70% drop in commercial citrus production in Florida and a closing of most of the citrus processing plants in that state. I have personally seen growers go out of business: sometimes a family business that went back many generations.  It has been a frustrating experience, and I have often asked myself: why is it taking so long to find solutions? This is a complicated question with many facets (including biological and global research structure issues). But it is in pursuit of the answer to this question that I have chosen to become a part of the ARS, Office of International Research Engagement and Cooperation (OIREC) EBCL team: to evaluate and potentially improve their role in addressing global issues of invasive pest/weed/pathogen species as early as possible and through team building to create integrated management solutions. 

In my 34 year career at the USDA, ARS, I have learned that the ARS stand apart from all other organizations conducting agricultural research (i.e. universities and private sector) by the potential ability to access a national network of scientists in a diverse array of disciplines that all share the same team of national directors and the same general goals:  developing solutions to agricultural problems and finding ways to keep U.S. agriculture healthy, competitive and able to supply low-cost diverse products to the consumers from environmentally sustainable production systems. I have also learned to understand the importance and strength of building multidisciplinary, interdisciplinary and transdisciplinary teams (simply defined as additive, interactive and holistic approaches, respectively) to solve complex agricultural problems. My passion for this type of team building has created a desire to do so on an international scale. Agricultural pests, weeds and pathogens obey no borders and thus international research only makes sense as we battle invasive species of these organisms. It is my desire to support the creation of international teams of great scientists to do great things-develop novel solutions to emerging threats to global agricultural and improve biosecurity for the U.S. and global food chain.

All of the ARS associated overseas laboratories (EBCL, France; the Australian Biological Control Laboratory (ABCL), Australia; the Foundation for the Study of Invasive Species (FuEDEI), Argentina; and the Sino-American Biological Control Laboratory (SABCL), China) have done excellent work on conducting CBC discovery and research activities that have had a significant positive impact on U.S. agriculture by addressing invasive pests, pathogens and weeds that represent challenges to U. S. environments and/or agriculture systems. Looking ahead, I see the potential to merge CBC with promising new biological methods to improve effectiveness. One example is the use of gene drive strategies.  A gene drive system is where an invasive organism is genetically manipulated, reared and released so that it mates with the pest population in the introduced range.  The genetic manipulations result in reduced fertility when mated with the already present invasive population resulting in a reduction or even elimination of the target invasive pest/weed population. Effectiveness of gene drive systems is partially based on achieving an appropriate ratio of the number of the released manipulated organism to the population size of the existing invasive population. By integrating CBC with a gene drive strategy, the invasive pest/weed population can be reduced to a level that improves the effectiveness of the gene drive releases. 

Another example is a novel method of pest/pathogen control developed by a team of which I have been a part. This is called the SymbiontTM system, and it is a novel strategy that uses a bacterium called Agrobacterium that typically causes crown gall disease.  In the Symbiont strategy, the bacterium is altered to play a beneficial protective role for the plant and not a disease. Agrobacterium naturally delivers a specific fragment of DNA directly into plant cells. As a pathogen, this bacterium delivers genes with several different functions: The two most notable are: 1) a set of genes encoding plant growth regulator (PGR) synthesizing enzymes that cause the plant cells to divide no longer under developmental control determined by the plan-thus a gall forms; 2) Genes encoding the biosynthesis of small molecules called opines that are used as food by the bacterium. In the Symbiont strategy, we remove the opine genes and modify the Agrobacterium so that it does not survive long after injecting the DNA into neighboring plant cells.  The DNA that is injected contains: 1) the PGR biosynthesis genes; and 2) a gene encoding a molecule of interest (i.e. a molecule that can either kill pests/pathogens or induce natural plant defenses to help the plant fight off pests/pathogens). The gall that is formed is called a SymbiontTM because of its overall beneficial function to the plant.  Successful Symbiont development was demonstrated in greenhouse experiments in tomato, potato and citrus, and an APHIS field trial permit has been submitted for evaluation of Symbionts ability to control HLB. The Agrobacterium is only necessary to transfer the DNA to the plant and, in citrus greenhouse experiments, the Agrobacterium population rapidly disappears. Also, the modified plant cells remain localized to where they were created and do not migrate, they die if removed and cannot form seed, pollen, or vegetative propagules. Therefore, this strategy mitigates the concern of environmental contamination by modified DNA or modified organisms.  We propose that combining CBC to control arthropod vectors of plant diseases with a Symbiont strategy to impart host plant disease resistance/tolerance could be an effective integrated pest management (IPM) strategy for invasive insect vectored disease problems. 

These are just two examples of how CBC could be combined with other emerging biologically-based methods to increase its effectiveness, and represent areas of research that I hope to advance through strategic collaborations with EBCL and U.S based researchers, and with interested international researchers. The future holds great promise for the development of integrated invasive pest/pathogen/weed control programs with a strong foundation in CBC and developed through strong international collaborations that allow early and creative development of effective control strategies. I am excited to be a part of this and look forward to writing more as our research advances. Now, please read on, and I hope you enjoy the wonderful articles in this newsletter as much as I have!


The European Biological Control Laboratory (EBCL) was established in 1991 near Montpellier, France. EBCL was created by the merger of the former European Parasite Laboratory, established in Paris in 1919, and the Biological Control of Weeds Laboratory in Rome. EBCL has a satellite laboratory in Thessaloniki, Greece. As the only USDA ARS-operated laboratory outside the United States, EBCL develops biological control technologies which can be used to suppress invading weeds and insect pests of Eurasian origin. EBCL researchers do this by searching for natural enemies (insects, mites, and pathogens) in their native habitat, determining their identity, testing their host specificity and potential impact in laboratory and field experiments, and shipping promising organisms to the U.S. for further testing as biological control agents. EBCL collaborates with scientists in many countries in Europe, Asia, and Africa to explore in regions of origin of the target weeds and insects.