At its origin in the mid-60’s BCIRL researchers focused on field studies to develop an ecological understanding of pest insects and beneficial agents in commodity cropping systems. By the mid-70’s weed projects were added to the overall program. In the early 80’s a molecular component was added to the program, launching work on biochemical processes underlying the interactions between beneficial agents and pest insects. These studies continue and useful products include several parasitoids, viruses, cell lines, and insect diets. Some of the early BCIRL accomplishments remain valuable:
· Discovery of the celery looper baculovirus, a potential biocontrol agent.
· Discovery of the diamond back moth baculovirus, another potential biocontrol agent.
· Invention of a diet and rearing system for beneficial insect parasitic wasps.
· Establishing cell lines from insect tissues: BCIRL scientists have established over 50 insect cell lines. Some of them have been provided to research groups throughout the world, where they support a very wide range of biological research.
Here are some recent BCIRL research accomplishments and their impacts.
Major accomplishments and their impacts:
1. Discovery of a fast-acting baculovirus as a
Use of baculoviruses (insect-specific pathogens) as biopesticides to control crop pests is growing at the globally, in part due to federal-level policies mandating reduced insecticide use in many countries. The effectiveness of these viruses is limited, however, by relatively slow kill speeds and environmental stability.
Two caterpillars, one healthy and the other
turning in a liquid after lethal baculovirus infection.
BCIRL scientists isolated a fast-acting baculovirus (SfMNPV) in Missouri that effectively kills fall armyworms (serious pest of many grain and legume crops) faster than other baculoviruses. This potent virus was discovered from nature through purification in cell cultures, not through genetic recombinant technology. SfMNPV has been completely characterized. Initial field work to document the efficacy of the virus was completed in 2011.
· The Australian firm, AgBiTech, is developing this fast-acting virus and its parent virus for commercial production in the U.S. AgBiTech is now working with the ARS Office of Technology Transfer, Beltsville, to launch a 2 year CRADA with BCIRL to support additional research needed to resister SfMNPV as a product for sale in the U.S. As a world-class expert on baculoviruses, BCIRL scientist Dr. Holly Popham worked with AgBiTech and the U.S. EPA to finalize research requirements to register SfMNPV as a commercial product in U.S.
· A second CRADA, at the inter-area level, will connect ARS units in Beltsville, Stoneville and BCIRL. This second CRADA will support research in mass production, formulation and application to produce and market the final product.
· SfMNPV is a socially acceptable, fast-acting agent that will contribute to the growing use of baculoviruses globally to improve environmental quality and food safety.
2. Nanoparticles in agriculture and environmental toxicology
Nanoparticles have been used since the 10th century in Persia. They were used to make ceramic glazes and used for bodily purification. They are now used in many industries, including cosmetics, sunscreens, dental filling materials, water purification and in photovoltaic cells to name a few of them. Although research into the toxicity and environmental pollution of nanoparticles is a very large research field, there is virtually no knowledge on the influence of these particles on insects or on their potential uses in agriculture.
BCIRL scientists established a tri-fold collaborative research program that links BCIRL, the commercial firm, Nanoparticle Biochem, Inc. (Columiba, MO) and Lincoln University (an 1890s institution, Jefferson City, MO). Building on preliminary research results showing silver nanoparticles are not directly toxic to insects, the collaborative team was awarded a three-year (2011 – 2013) NIFA grant ($240,000) to investigate use of silver nanoparticles as potential baculovirus delivery vehicles and continue insect toxicological investigations. The research team is a multi-disciplinary group, involving chemists, physicists, bio-medical specialists and entomologists.
Despite their long and wide-spread use, many questions about the toxicology and beneficial uses of nanoparticles in agriculture remain unasked and unanswered. We already are producing new knowledge that will be applied to deploy silver nanoparticles technology in environmentally sophisticated ways toward agricultural uses. The first research into these uses is focused on baculovirus delivery vehicles.
3. Significance of insect immune systems in crop production and protection
Since the earliest, late 19th century days of immunology, people have been studying insect immune systems. Research since then has revealed detailed understanding of the mechanisms of insect immunity. However, virtually all of the research had been carried out on insect species cultured under fairly clean or even sterile conditions in laboratories. The significance of insect immunity with respect to the biological control of insects in agricultural fields had not been investigated.
BCIRL scientists conducted a multi-year field study designed to assess the question of whether insects are infected in farm fields. The published results showed that ALL of the more than 500 specimens examined in the laboratory had been infected at least once and had recovered from the infections and continued consuming (and damaging) crops.
A wheat field under unseen insect attack
This research demonstrated the potent ability of insect immune systems to kill invading microorganisms and parasites. The significance of the work lies in understanding that insect immunity limits the effectiveness of biological control agents. BCIRL scientists used this information in a call for a shift in research directions away from basic research designed to further understand immunity and towards research designed to use current knowledge to cripple insect immune responses to biological control agents. BCIRL and other scientists world-wide are researching mechanisms to impair the ability of insects to protect themselves from biological control agents.
4. Proof of concept: Impairing insect immunity by gene silencing
Although the idea of impairing insect immune reactions to biological control agents has attracted a great deal of attention, questions of which elements of the immune system are vulnerable to impairment had not been answered.
BCIRL scientists, working with national and international collaborators, identified a specific gene that is an essential component of the biochemical signaling necessary in immune responses to infection. They applied emerging gene silencing technologies to block expression of the gene and showed that silencing the gene impaired immune reactions in insects.
This work has stimulated related research at the national and international levels and is the basis for one of the recently approved CRIS projects in BCIRL. At the global level, this is a rapidly-moving research area; this and related technologies will be in commercial development within the next 5 years.
5. Discovery of a novel mechanism of insect anti-viral immunity
Insects express robust immune responses to infections, both natural infections and infections resulting from releasing biological control agents. As mentioned just above, insect responses to bacterial, parasitic and fungal infections are well understood, however, there is very little knowledge on how insects protect themselves from baculoviruses. This is a crucial shortcoming because baculoviruses have the most promise as biological control agents.
BCIRL scientists discovered an enzyme that is always present in insect blood (hemolymph) circulation responsible for killing baculoviruses. They identified the enzyme and directly showed it is a novel element in insect immune reactions to viral infections.
· This discovery introduced a new anti-viral mechanism in contemporary understanding of insect immunology. The discovery immediately led to detailed research, now published, to characterize the enzyme and understand how it kills baculoviruses.
· This enzyme now stands as one of the premier targets researchers around the world focus on in their work to impair insect immune reactions to biological control agents.
6. Nutritional deficiencies influence gene and protein expression in insects
Mass rearing programs produce beneficial insects for large-scale releases into agricultural fields and they produce pest insects for sterilization and release in sterile insect technologies to suppress pest populations. Mass rearing programs are expensive and a great deal of research is directed toward developing cost-effective culture media. Research in this area is a very expensive and long-term enterprise because insects must go through two or more generations to identify nutritional deficiencies.
BCIRL scientists developed protocols to identify genetic and protein biomarkers for nutritional deficiencies. The use of biomarkers can multiply the speed of developing useful culture media because the biomarkers can be detected very early in rearing cycles.
Aside from publications in the scientific literature and their impact on other scientists, this research and the training required to conduct the research have been transferred to one ARS unit, where is now a major research component and will be transferred to another ARS unit involved in understanding the influence of diet components on beneficial insect ecology.
7. Novel strategy for releasing predatory beneficial insects
Beneficial predatory insects are very effective in controlling a wide range of insect pests of vegetables in organic and other value-added gardens. However, the effectiveness of the predatory insects is severely reduced in some cases because the predators fly away before they can impact pest populations.
BCIRL scientists developed an early-release strategy in which predatory juveniles (cannot fly away) and chemical aggregation signals that draw additional predators from nearby overwintering sites are deployed before pest infestations begin.
· University of Missouri and Lincoln University extension programs have demonstrated this protocol to over 200 vegetable producers in Missouri.
· Lincoln University faculty members collaborate with BCIRL scientists to continue research on this novel release strategy.
· BCIRL scientists have directly demonstrated the effectiveness of this system in the BCIRL Demonstration Garden, located on the BCIRL site, and in community garden projects.
8. Invention of an artificial culture medium for beneficial predatory insects
Predatory insects are mass produced by commercial firms throughout the world. The major problem limiting production of these important biological control agents is the high cost of rearing a prey insect species to support the beneficial predatory insects.
BCIRL scientists invented a completely artificial medium that supports production of healthy and highly efficacious predatory insects at competitive costs.
· The artificial culture medium is used globally in research programs and in commercial beneficial insect production programs to rear high quality beneficial insects.
· International visiting and sabbatical professors have spent months in BCIRL, learning and applying the culture medium to related beneficial insect species.
· The medium reduced costs of production and increased use of beneficial insects in organic and Integrated Pest Management programs.