Location: European Biological Control Laboratory
2021 Annual Report
Objectives
To search for, identify, and evaluate the potential of natural enemies of pest insects, weeds, and plant diseases that affect Chinese and U.S. agriculture.
Objective 1: Explore for arthropod natural enemies of invasive arthropod pests and weedy plants identified as high priority targets by the ARS Office of National Programs, performing collections, importations and exportations in compliance with local and international regulations. High priority targets include, but are not limited to, giant cane, cogon grass, cattle fever tick, Asian longhorned beetle, emerald ash borer, brown marmorated stink bug, bean plataspid, spotted wing drosophila, spotted lantern fly, and wheat stem sawfly. (non-hypothesis driven) [NP304, Component 2, Problem Statements 2A3 and 2B3]
Objective 2: Perform taxonomic and phylogenetic studies of targets and their natural enemies, as needed to support development of biological control agents. (non-hypothesis driven) [NP304, Component 1, Problem Statement 1B]
Objective 3: Conduct studies to identify the biological and physical parameters that affect the efficacy and safety of potential agents, including climatic conditions, host specificity, effective rearing conditions, and biogeography. [NP304, Component 2, Problem Statements 2A3 and 2B3]
Approach
Survey for, collect and identify natural enemies of agricultural and landscape pests. Make field collections, establish laboratory colonies when needed, and ship candidate agents to the U.S. for further evaluation. Conduct preliminary host
specificity tests on promising parasites, predators, and beneficial microorganism. Collect, colonize, and ship to the U.S., candidates found to be safe. Cooperate with USDA and State laboratories in future collections for shipment and evaluation for release. Collect natural enemies attacking pests at differing host densities and climatic zones. All natural enemies selected for shipment will be sent directly to State or Federal quarantine facilities in the U.S. for further evaluation. Both Chinese and American scientists share the same right of obtaining biological control agents collected from the two countries. Assist in obtaining the necessary regulatory agency permissions for exporting live material from China.
Progress Report
Using DNA metabarcoding for assessing insect diversity in different kinds of crops in China. The current study analyzed the composition of the insect communities in potato and maize in Yunnan and citrus orchards in Jiangxi in China using DNA metabarcoding. Species revealed by BINs matches on BOLD were classified to pests, parasitoids, predators and pollinators. The study presents the first baseline data on insect biodiversity in potato, maize and citrus plantations in China which offers a valuable resource for research in a broad range of areas such as beneficial insect exploration, pest management and monitoring.
Determining the distribution and natural enemy complex of the Roseau cane scale in China. In 2021, Sino-ABCL continued to determine the distribution and natural enemy complex of the Roseau cane scale in China, including Beijing, Hebei, Guangxi and Shandong. According to the survey plan, we will get 3 rounds of field survey as before. Up to now, Sino-ABCL together with local collaborators have completed the first round of field survey. In addition, Sino-ABCL transferred the specimens to US, including host plant, scale and parasitoids.
Insight into the functional diversification of lipases in the predatory bug Arma chinensis by genome-scale annotation and expression analysis. Lipases play essential roles in digestion, transport, and processing of dietary lipids in insects. As a “true bug,” A. chinensis belongs to the sub-order Heteroptera, and to the family Pentatomidae, which encompasses all stink bugs. A. chinensis is a predaceous bug that preys upon a large variety of pests, and can effectively suppress agricultural and forest pests in the orders Lepidoptera, Coleoptera. Like most of terrestrial predaceous arthropods, A. chinensis used extra-oral digestion as a tool of utilizing relatively large preys. These predators obtain prey extraction and nutrient concentration by refluxing or non-refluxing application during injection of hydrolytic enzymes including lipases. Arma chinensis genome and transcriptome data were interrogated. Multiple alignments and phylogenetic trees were constructed. We annotated a total of 41 predicted lipase genes belonging to five lipase families. To investigate the enzyme activities and potential functions of A. chinensis lipases, we determined enzyme activities of salivary gland and midgut by use of ELISA. In addition, we performed lipase metabolomics by use of LC-MS.
Developing the technology of mass rearing of biological agents. Large numbers of high-quality biological control agents are fundamental prerequisites to successful integration of augmentative biological control and thus, to the success of mass rearing programs. Several predator colonies are maintained in Sino-ABCL, including A. chinensis, lacewing, and lady beetle. We developed artificial diets for these predators and improved the rearing apparatus and environmental conditions accordingly. Studies on evaluation of the quality indicators for the mass rearing of biological agents were also conducted.
Accomplishments
1. There are more insect pests in citrus orchards in China than previously known. Citrus is an important economical crop throughout the world where it is grown. Citrus pests severely limit production and therefore economic returns. Pest surveys on citrus were conducted in China, which is considered to be one of the centers of origin of citrus. Collected insects from citrus orchards in China were analyzed by their DNA and grouped as either pests or beneficials. Results showed that the number of pests is far more than that has been documented in the literature on citrus pests in China. The data generated in this study provides a valuable resource for research in a broad range of areas such as citrus pest management and monitoring program.
2. Predator bugs use multiple saliva and midgut enzymes to feed. Certain enzymes are important in digesting, transporting, and processing of dietary lipids in insects. Understanding what enzymes are used when the insects feed can lead to better artificial diets for mass production. By using gene analysis tools, different types of lipase enzymes in the salivary gland and midgut of the predatory bug Arma chinensis were discovered. In addition, it was discovered that the total activities of the lipase enzymes in the salivary gland was higher than that of midgut. The current results suggested fatty materials can be added into the artificial diet for mass rearing this predacious bug. Arma chinensis is a predaceous bug that preys upon a large variety of agricultural pests, including Colorado potato beetle, which has developed resistance to most insecticides. Being able to make an artificial diet to grow this insect will benefit agricultural producers who want to release this insect as a biological control agent.
