Objective 1: Discover, develop and implement semiochemical-based control and monitoring methods for key pests of orchard crops including, but not limited to, Asian citrus psyllid, citrus leafminer, citrus canker disease, and the Diaprepes root weevil. Sub-objective 1a: Identify physiologically active odorants and attractant blends for detection and monitoring of ACP. Sub-objective 1b: Complete large scale tests and promote adoption of CLM mating disruption. Sub-objective 1c: Identify attractants for DRW and Sri Lankan weevil. Objective 2: Identify sources of resistance and characterize traits and mechanisms conferring plant resistance to the Asian citrus psyllid in Citrus and near-Citrus relatives. Sub-objective 2a: Identify and determine the underlying mechanism of resistance in Poncirus trifoliata to oviposition by Asian citrus psyllid (ACP). Sub-objective 2b: Describe feeding behavior of ACP on susceptible and resistant citrus and near-citrus germplasm. Objective 3: Develop and implement new and improved biological control strategies for key pests of citrus, including Asian citrus psyllid, using existing and new natural enemies. Sub-objective 3a: Biological control of Asian citrus psyllid by Hirsutella citriformis. Sub-objective 3b: Development of an autodisseminator of entomopathogens to suppress ACP populations. Objective 4: Develop and implement control of key pests and vectors including, but not limited to, Asian citrus psyllid by 1) identifying interdiction points in key biological processes through genomics, proteomics and metabolomics, 2) identifying inhibitors (dsRNA, peptides, chemicals), and 3) developing delivery methods, e.g., transgenic plants and topical applications of exogenous compounds. Sub-objective 4a: Combining molecular/cellular biology (including targeted and omics level research) with bioassays to identify interdiction molecules including but not limited to dsRNAs (as RNAi inducers), peptides, peptidomimetics and RNA aptamers that block key molecular events in targeted processes such as, but not limited to, salivary sheath formation, specific digestive processes, and/or disease transmission. Sub-objective 4b: Develop delivery strategies for interdiction molecules.
Insect-plant interactions are varied and complex. The processes of host location, selection, feeding, and oviposition are only broadly understood, and for relatively few species. In the case of recent arrivals of invasive pests of orchard crops, these aspects of pest biology are not understood in the detail required to design appropriate, novel, and environmentally sound management strategies, such as the following examples. Information-transmitting odors (semiochemicals) can often be inexpensively synthesized and used to interfere with insect pest behavior. Also, understanding the physical or biochemical basis for plant resistance to insects allows engineering or selection of crop varieties with endogenous resistance. In the case of invasive vectors of plant pathogens, lack of understanding of the mechanisms of pathogen transmission (i.e., acquisition, retention and inoculation) further impedes progress in pest management. These mechanisms are also complicated, and are layered onto the complex biological processes described above. The objectives of this project focus on both vector and non- vector pests in orchards. They address discovery, study and utilization of: 1) semiochemicals and other physical or chemical bases of host plant resistance, 2) mechanisms involved in host plant resistance in compatible near-Citrus germplasm, 3) new biological control agents and novel utilization of known ones, and 4) key biological processes that represent opportunities for interdiction of insect-host interactions. Together, these projects aim to design all-new biological control and non-pesticidal management strategies. An advantage of these approaches is their compatibility with existing, especially pesticidal, methods in citriculture. Several of the approaches are broadly applicable to a range of subtropical orchard crops.