Research Project: IPM Methods for Insect Pests of Orchard Crops

Location: Subtropical Insects and Horticulture Research

2017 Annual Report

Objectives
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.

Approach
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.

Progress Report
Progress was achieved toward all objectives during the second year of this project. Progress included commercialization of a mating disruption product for citrus leafminer, discovery of phagostimulatory properties of common plant volatiles for Asian citrus psyllid, and the role of methyl jasmonate in plant resistance to the psyllid. Histological studies and electronic recordings of psyllid feeding led to elucidation of mechanisms of plant resistance in near-citrus relatives. Machine learning produced algorithms to allow computer classification of waveforms produced by sucking insects, thereby extending the utility of electronic recording and providing insights into mechanisms of plant resistance. Field surveys identified six trifoliate orange cultivars resistant to psyllid oviposition. Commercialization of mating disruption for control of citrus leafminer is complete; further research is not anticipated. ISCA Technologies, Inc. (Riverside, California) produces and markets a product based on research by ARS into optimal pheromone blend, device loading rates and deployment. Resources and focus have now shifted to the critical issue of Asian citrus psyllid and citrus greening disease. A collaborative project was initiated to develop an improved trap for Asian citrus psyllid. Twenty compounds suggested to be involved in attraction are being screened. A combination of phagostimulants and low doses of insecticide compared with insecticide alone in a wax substrate was demonstrated to increase psyllid mortality. This effect is expected to be of value in constructing an effective attract-and-kill device. The electronic penetration graph (EPG) is uniquely able to describe movement and behavior of sucking insects’ mouthparts within host plant tissues. A major limitation is the time-consuming coding of wavelengths by an observer. We published a set of algorithms that allow computer classification of waveforms thereby reducing the time required to analyze EPG data. When provided with 5% of a 20 hour recording, the computer classified the remaining 95% of the data with 97% accuracy. This work demonstrates the potential for application of machine learning to automate EPG analysis. Histological analysis and electronic penetration graph (EPG) illustrated how a fibrous ring of cells (sclerenchyma) in developing citrus leaves interferes with psyllid feeding by impeding passage of psyllid mouthparts. Sustained feeding on phloem of infected plants is required for pathogen acquisition and transmission. Thick-walled fibrous sclerenchyma surrounding phloem of mature leaves reduced ingestion by psyllids on lower leaf surfaces compared with ingestion from upper surfaces of mature leaves or on young leaves. The longest ingestion period was observed on upper sides of young leaves with the least developed sclerenchyma. These results support the hypothesis that thick, well-developed fibrous cells around phloem act as a barrier to ingestion. This may limit or prevent acquisition and/or transmission of citrus greening pathogen by the psyllid, and could be used for development of resistant citrus cultivars. Volatiles emitted by healthy and citrus greening-infected ‘Valencia’ trees were changed when sprayed with methyl jasmonate. Methyl jasmonate decreased emission of methyl salicylate emitted by infected plants that may be attractive to Asian citrus psyllid. Methyl jasmonate applications may reduce attractiveness of young citrus shoots to the psyllid. A field survey revealed low infestations of Asian citrus psyllid on trifoliate orange cultivars compared with conventional citrus and citrange cultivars (hybrids of sweet orange and trifoliate orange). Reduced colonization was a result of reduced oviposition. Foliar trichomes (tiny hair-like structures) confer resistance to insects in many crops. Trichomes were most abundant on curry leaf and orange jasmine, genotypes often heavily colonized by psyllid. Reduced colonization did not appear to be a function of trichomes. Reasons for trifoliate resistance have not been identified; factors associated with mature leaves may be involved. Psyllids laid 58% fewer eggs on a susceptible plant when trifoliate orange leaves were present. When the psyllid was allowed to lay eggs in the presence of volatiles from trifoliate orange leaves (but not leaves themselves), 23% fewer eggs were laid. Reduced psyllid infestations may be caused by volatiles from mature leaves. Accessions of the bacterium Bacillus thuringiensis were screened for toxicity to adult psyllids. An invention disclosure was filed showing that combinations of toxins derived from six bacterial strains were toxic to the psyllid. Colonies of Asian citrus psyllid were established from individual females collected at Florida locations. Iso-female lines were compared for ability to acquire and transmit the greening pathogen. Acquisition rates ranged from 5 to 32% and were variable within lines. Incidence of the citrus greening bacterium was assessed in a Florida population of Asian citrus psyllids. More females carried the bacterium than males. The degree of bacterial infection of three psyllid color morphs was similar. A mean of 17% of adults carried the pathogen. Infection was higher during winter (>40%) and lower during summer (<10%). Twenty-two repellents were tested against the psyllid. Sixteen of these were repellent in laboratory assays; none was 100% repellent. In greenhouse studies with repellents applied directly to plants, reductions in psyllid infestation occurred but was confounded by phytotoxicity. Citrus breeders at Fort Pierce, Florida, are developing new varieties for resistance to citrus greening. A high-throughput inoculation program was established to expedite evaluations. Over 10,000 plants were screened using over 300,000 psyllids. The occurrence of lady beetles, natural enemies of Asian citrus psyllid (ACP), was measured on two species of native plants. Twelve species known to attack ACP were collected. These plants may support lady beetle populations and decrease ACP numbers. Tests were conducted on efficacy of autodisseminators of the entomopathogenic fungus Isaria fumosorosia in suppressing psyllid populations in residential citrus. Lime trees with autodisseminators had fewer psyllid eggs than trees without autodisseminators. Trees with autodisseminators had fewer adult psyllids than control trees. A Material Transfer Agreement was developed with a commercial collaborator to conduct field tests of citrus infected with a citrus triseza virus (CTV) vector expressing double-stranded ribonucleic acid (dsRNA) molecules that induce psyllid mortality. Specific dsRNAs were chosen that resulted in significant psyllid mortality on greenhouse citrus infected with the CTV vector. Plants have been provided to collaborators for field trials. Bioassays were developed to screen molecules for bactericidal activity against the citrus greening pathogen. Bioassays identified a novel peptide that reduced detectable greening bacteria in leaves by 90% after 6 days. Three peptides were shown to bind to psyllid gut epithelium and inhibit pathogen acquisition. In combination, these peptides induced greater than 90% psyllid mortality. None of the surviving psyllids contained detectable citrus greening causing bacteria in their salivary glands. Evaluation of bactericide formulations continued in commercial groves. Repeated applications continued to improve citrus health and yields. These data supported a section 18 regulatory approval for Florida citrus. The complete Asian citrus psyllid genome and official gene set were posted to the NCBI database. Genomic data were used to design double-stranded ribonucleic acid (dsRNA) treatments to target key biological processes of the psyllid using ribonucleic acid interference (RNAi) that has the potential to function as an alternative biopesticide strategy for highly specific psyllid control. A patent was submitted. High resolution image mapping of psyllid anatomy was performed using Micro-CT scanning that permits digital sectioning and rotational viewing. This basic anatomical data is being used in conjuction with various –omics projects to identify basic biological functions that can serve as targets for new control strategies (e.g., Ribonucleic acid interference (RNAi). A manuscript was published on the methods and an improved contrasting agent was developed that improved images of internal psyllid anatomy. The difficulty of dsRNA delivery into plants and rapid degradation of exogenously applied double-stranded ribonucleic acid (dsRNA) limits practical applications of RNAi in commercial agriculture. We developed a delivery system for dsRNA using clay as a soil amendment for potted plants, row crops and citrus trees. Clay particles mixed with dsRNA extended dsRNA persistence up to 8 months post-treatment. This method provided significantly longer protection compared with topically applied products. A small peptide was identified and demonstrated to improve dsRNA-induced mortality. A commercial partner was identified and an agreement was filed for further development. Chemical adjuvants to improve citrus tree absorption of topically applied double-stranded ribonucleic acid (dsRNA) were compared. One chemical significantly improved uptake of dsRNA by plants; an invention disclosure was filed. Work is underway with a commercial partner and may provide a viable commercial product for deployment of dsRNAs as a biopesticide for citrus and other crops.

Accomplishments
1. Bactericides against the citrus greening disease pathogen continue to improve health of sytomptomatic citrus trees with multiple year applications. ARS researchers at Fort Pierce, Florida, provided data to support a Section 18 approval for their use and have now demonstrated that multiple years of treatment can lead to continued improvements in the health and productivity of infected trees. Data provided to the State of Florida and the Environmental Protection Agency were the basis for continued approval of these bactericides for use in Florida. An August 2016 survey of growers representing 240,305 acres of Florida citrus indicated that 84% (201,724 acres) would be treated season-long with bactericides during 2016-2017.

2. Promising peptide combination kill psyllids and block acquisition of the bacterium causing citrus greening. ARS researchers at Fort Pierce, Florida, identified a peptide that kills the bacterium associated with the greening disease. They also identified a set of three different peptides that reduce the bacterium’s ability to successfully move from the psyllid gut to the salivary glands, a process necessary for successful acquisition by the psyllid and subsequent transmission of the bacterium to uninfected citrus. When the four peptides were fed to psyllids, 90% mortality was observed. None of the surviving psyllids contained detectable citrus greening bacteria in their salivary glands. This peptide combination provides a new strategy to fight the psyllid and the bacterium responsible for citrus greening.

3. New Integrated Pest Management (IPM) strategies for Asian citrus psyllid. ARS researchers at Fort Pierce, Florida, have identified aspects of psyllid biology, host plant relations and biological control that are expected to contribute to an integrated approach for environmentally appropriate control of this pest. A blend of feeding stimulants was discovered that may be useful in traps and attract-and-kill devices. Progress was made in identifying chemical traits in trifoliate orange that may be transferred to sweet orange and grapefruit to confer resistance to the psyllid. Complementary methods were developed to promote biological control by predators and an entomophagous fungus. Integration of these advances will facilitate reductions in reliance on intensive pesticide programs.

4. Histological studies and electronic recording of psyllid feeding demonstrate why Asian citrus psyllids require young leaves. A fibrous ring of thick-walled cells (sclerenchyma) around the phloem, absent from young leaves, becomes prominent in mature citrus leaves. The longest duration of phloem ingestion was observed from psyllids placed on the upper side of young leaves that had the least developed sclerenchyma. Epifluorescence microscopy showed that the fibrous ring in young leaves was thinner and incomplete compared with mature leaves. The presence of a thick, well-developed fibrous ring around phloem tissues of mature leaves acts as a barrier to phloem ingestion. This may have an important role in limiting or preventing acquisition and/or transmission of the greening pathogen by the psyllid, and could be used for identification and development of resistant citrus cultivars.

Review Publications
Willett, D.S., George, J., Willett, N.S., Stelinski, L.L., Lapointe, S.L. 2016. Machine learning for characterization of insect vector feeding. PLoS Computational Biology. 12(11):e1005158
Arp, A.P., Hunter, W.B., Pelz-Stelinski, K. 2016. Annotation of the Asian citrus psyllid genome reveals a reduced innate immune system. Frontiers in Physiology. 7:570.
Ponsankar, A., Vasantha-Srinivasan, P., Senthil-Nathan, S., Thanigaivel, A., Edwin, E., Selin-Rani, S., Kalaivani, K., Hunter, W.B., Alessandro, R.T., Abdel-Megeed, A., Paik, C., Duraipandiyan, V., Al-Dhabi, N. 2016. Target and non-target toxicity of botanical insecticide derived from Couroupita guianensis L. flower against generalist herbivore, Spodoptera litura Fab. and an earthworm, Eisenia foetida Savigny. Ecotoxicology and Environmental Safety. 133:260-270.
George, J., Ammar, E-D., Hall, D.G., Lapointe, S.L. 2017. Sclerenchymatous ring as a barrier to phloem feeding by Asian citrus psyllid: Evidence from electrical penetration graph and visualization of stylet pathways. PLoS One. doi:10.1371/PO.2017-0173520
Martini, X., Hughes, M.A., Killiny, N., George, J., Lapointe, S.L., Smith, J.A., Stelinski, L.L. 2017. The fungus Raffaelea lauricola modifies behavior of its symbiont and vector, the redbay ambrosia beetle (Xyleborus glabratus), by altering host plant volatile production. Journal of Chemical Ecology. 43:519-531
Stover, E.W., Hall, D.G., Shatters, R.G., Moore, G.A. 2016. Influence of citrus source and test genotypes on inoculations with Candidatus Liberibacter asiaticus. HortScience. 51:805-809.
Hall, D.G., Ammar, D., Bowman, K.D., Stover, E.W. 2017. Epifluorescence and stereomicroscopy of trichomes associated with resistant and susceptible host plant genotypes of the Asian citrus psyllid (Hemiptera: Liviidae). Journal of Microscopy and Ultrastructure. Available: http://www.sciencedirect.com/science/article/pii/S2213879X17300020.
Mahmoud, S., Ramos, J.E., Shatters, R.G., Hall, D.G., Lapointe, S.L., Niedz, R.P., Rouge, P., Borovsky, D. 2016. Expression of Bacillus thuringiensis cytolytic toxin (Cyt2Ca1) in citrus roots to control Diaprepes abbreviatus larvae. Pesticide Biochemistry and Physiology. 136:1-11.
Ammar, E.D., Hall, D.G., Shatters, R.G. 2017. Ultrastructure of the salivary glands, alimentary canal and bacteria-like organisms in the Asian citrus psyllid, vector of citrus huanglongbing-disease bacteria. Journal of Microscopy and Ultrastructure. 5(1):9-20.
Ghosh, S.B., Hunter, W.B., Park, A.L., Gundersen, D.E. 2017. Double strand RNA delivery system for plant-sap-feeding insects. PLoS One. doi:10.1371.
Kolora, L., Powell, C.M., Hunter, W.B., Bextine, B., Lauzon, C.R. 2015. Internal extracellular bacteria of Diaphorina citri Kuwayama (Hemiptera: Psyllidae), the Asian citus psyllid. Current Microbiology. 70:710-715.
Ramsey, J.S., Johnson, R., Hoki, J., Kruse, A., Mahoney, J., Hilf, M.E., Hunter, W.B., Hall, D.G., Shroeder, F., Maccoss, M., Cilia, M. 2015. Metabolic interplay between the Asian citrus psyllid and its Profftella symbiont: An Achilles’ heel of the citrus greening insect vector. PLoS One. DOI: 10.1371/journal.pone.0140826.
Ferrara, T., Schneider, V.K., Kishi, L.T., Carmona, A.K., Alves, M., Belasque-Junior, J., Rosa, J.C., Hunter, W.B., Henrique-Silva, F., Soares-Costa, A. 2015. Characterization of a recombinant Cathepsin B-Like cysteine peptidase from Diaphorina citri Kuwayama (Hemiptera: Liviidae): A putative target onctrol of citrus huanglongbing. PLoS One.
Chen, W., Hasegawa, D.K., Kaur, N., Kliot, A., Pinheiro, P.V., Luan, J., Stensmyr, M.C., Zheng, Y., Liu, W., Sun, H., Xu, Y., Luo, Y., Kruse, A., Yang, X., Kontsedalov, S., Lebedev, G., Fisher, T., Nelson, D.R., Hunter, W.B., Brown, J.K., Jander, G., Cilia, M., Douglas, A.E., Ghanim, M., Simmons, A.M., Wintermantel, W.M., Ling, K., Fei, Z. 2016. The draft genome of whitefly Bemisia tabaci MEAM1, a global crop pest, provides novel insights into virus transmission, host adaptation, and insecticide resistance. BMC Biology. 14:110 doi:10.1186/s12915-016-0321-Y.
Tufts, D.M., Hunter, W.B., Bextine, B.R. 2014. Solenopsis invicta virus (sinv-1) infection and insecticide interactions in the red imported fire ant (Hymenoptera: Formicidae). Florida Entomologist. 97(3):1251-1254.
Biesbrock, A.M., Powell, C.M., Hunter, W.B., Bextine, B.R. 2014. Propagation of Homalodisca Coagulata Virus-01 via Homalodisca Vitripennis cell culture. Journal of Visualized Experiments. 91. e51953-e51953
Monti, M., Mandrioli, M., Bextine, B., Hunter, W.B., Alma, A., Tedeschi, R. 2014. Maintenance of primary cell cultures of immunocytes from Cacopsylla sp. psyllids: a new in vitrio tool for the study of pest insects. In Vitro Cellular and Developmental Biology - Animals. https://doi.org/10.1007/s11626-014-9785-7.
Selin-Rani, S., Senthil-Nathan, S., Thanigaivel, A., Vasantha-Srinivasan, P., Edwin, E., Ponsankar, A., Lija-Escaline, J., Kalaivani, K., Abdel-Megeed, A., Hunter, W.B., Alessandro, R.R. 2016. Toxicity and physiological effect of quercetin on generalist herbivore, Spodoptera litura Fab. and a non-target earthworm Eisenia fetida Savigny. Chemosphere. 165:257-267.
Coates, B.S., Poelchau, M.F., Childers, C., Evans, J.D., Handler, A.M., Guerrero, F., Skoda, S.R., Hopper, K.R., Wintermantel, W.M., Ling, K., Hunter, W.B., Oppert, B.S., Perez De Leon, A.A., Hackett, K.J., Shoemaker, D.D. 2015. Arthropod genomics research in the United States Department of Agriculture-Agricultural Research Service: Current impacts and future prospects. Trends in Entomology. 11(1):1-27.
Lapointe, S.L. 2015. A tribute to Dr. Anthony C. Bellotti and his contributions to cassava entomology. Florida Entomologist. 98(2):810-814.
Lapointe, S.L., Hall, D.G., George, J. 2016. A phagostimulant blend for the Asian citrus psyllid. Journal of Chemical Ecology. 42(9):941-951
Willett, D..S., Stelinski, L.L., Lapointe, S.L. 2015. Using response surface methods to explore and optimize mating disruption of the leafminer Phyllocnistis citrella (Lepidoptera: Gracillariidae). Frontiers in Ecology and Evolution. 3:30.
Hall, D.G., George, J., Lapointe, S.L. 2015. Further investigations on colonization of Poncirus trifoliata by the Asian citrus psyllid. Crop Protection. 72:112-118.
Stover, E.W., Shatters, R.G., Gruber, B., Kumar, Moore, G.A. 2016. Influence of photoperiod duration and phloem disruption through scoring on growth, disease symptoms and bacterial titer in citrus graft-inoculated with Candidatus Liberibacter asiaticus. HortScience. 51:1215-1219.
Van Ekert, E., Powell, C.A., Shatters, R.G. Jr., Borovsky, D. 2014. Control of larval and egg Development in Aedes aegypti with Ribonucleic acid interference (RNAi) against juvenile hormone acid methyl transferase. Journal of Insect Physiology. doi:10.1016/IP.2014-08001.
Ben-Mahmoud, S., Ramos, J.E., Shatters, R.G., Rouge', P., Powell, C.A., Smagghe, G., Borovsky, D. 2014. Cloning and characterization of a basic cysteine-like protease (cathespsin L1) expressed in the gut of larval Diaprepes abbreviatus L. (Coleoptera: Curculionidae). Journal of Insect Physiology. (72):1-13.
Ammar, E., Hall, D.G., Shatters, R.G. 2015. Ultrastructure and development of the new stylets inside pre-molting first instar nymphs of the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae). Florida Entomologist. 98:373-376.
Stover, E.W., Mccollum, T.G., Ramos, J.E., Shatters, R.G. 2015. Growth, health and Liberibacter asiaticus titer in diverse citrus scions on mandarin vs. trifoliate hybrid rootstocks in a field planting with severe huanglongbing. Proceedings of Florida State Horticultural Society. 127:53-59.
Ammar, E., Hentz, M.G., Hall, D.G., Shatters, R.G. 2015. Ultrastructure of wax-producing structures on the integument of the melaleuca psyllid Boreioglycaspis melaleucae (Hemiptera: Psyllidae) and honeydew excretion behavior in males and females. PLoS One. doi: 10.1371/PO.2015-0121354.
Barr, N., Ruiz-Arce, R., Obregon, O., Shatters, R.G., Norrbom, A.L., Nolazco, A., Thomas, D.B. 2017. Diagnostic characters within ITS2 DNA support molecular identification of Anastrepha suspensa. Florida Entomologist. 100:182-185.
Ammar, E., Richardson, M.L., Abdo, Z., Hall, D.G., Shatters, R.G. 2014. Differences in stylet sheath occurrence and the fibrous ring (sclerenchyma) between xCitroncirus plants relatively resistant or susceptible to adults of the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae). PLoS One. doi: 10.1371/PO.2014-0110919.
Van Ekert, E., Heylen, K., Rouge, P., Powell, C.A., Shatters, R.G., Smagghe, G., Borovsky, D. 2014. Aedes aegypti juvenile hormone acid methyl transferase, the ultimate enzyme in the biosynthetic pathway of juvenile hormone III, exhibits substrate control. Journal of Insect Physiology. 64:62-73.
Dickey, A., Kumar, V., Morgan, J.K., Jara-Cavieres, A., Shatters, R.G., McKenzie, C.L., Osborne, L. 2015. A novel mitochondrial genome architecture in thrips (Insecta: Thysanoptera): extreme size asymmetry among chromosomes and possible recent control region duplication. BMC Genomics. 16:439. doi:10.1186/s12864-015-1672-4.
Backus, E.A., Shugart, H.J., Rogers, E.E., Morgan, J.K., Shatters, R.G. 2015. Direct evidence of egestion and salivation of Xylella fastidiosa suggests sharpshooters can be “flying syringes”. Phytopathology. 105:608-620.
Ammar, E-D., Ramos, J.E., Hall, D.G., Dawson, W.O., Shatters, R.G. 2016. Acquisition, replication and inoculation of Candidatus Liberibacter asiaticus following various acquisition periods on Huanglongbing-infected citrus by nymphs and adults of the Asian citrus psyllid. PLoS One. doi:10.1371/PO.2016-0159594
Dickey, A.M., Kumar, V., Hoddle, M.S., Funderburk, J.E., Morgan, J.K., Jara-Cavieres, A., Shatters, R.G., Osborne, L.S., McKenzie, C.L. 2015. The Scirtothrips dorsalis species complex: Endemism and invasion in a global pest. PLoS One. https://doi.org/10.1371/journal.pone. 0123747
Dickey, A.M., Trease, A.J., Jara-Cavieres, A., Kumar, V., Christenson, M.K., Potluri, L.P., Morgan, J.K., Shatters, R.G., McKenzie, C.L., Davis, P.H., Osborne, L. 2014. Estimating bacterial diversity in Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) via next generation sequencing. Florida Entomologist. 97(2):362-366.
Hall, D.G., Hentz, M.G., Patt, J.M. 2015. Behavioral assay on Asian citrus psyllid attraction to orange jasmine. Journal of Insect Behavior. 28:555-568.
Stockton, D.G., Martini, X., Patt, J.M., Stelinski, L.L. 2016. The influence of learning on host plant preference in a significant phytopathogen vector, Diaphorina citri. PLoS One. doi: 10.1371/PO.2016-0149815.
Mullen, E.R., Rutschman, P., Pegram, N., Adamczyk Jr, J.J., Patt, J.M., Johanson, E. 2016. Laser system for identification, tracking, and control of flying insects. Optics Express. 24(11):11828. doi:10.1364/OE.24.011828.
Chow, A., Dunlap, C.A., Jackson, M.A., Flores, D., Patt, J.M., Setamou, M. 2016. Oviposition behavior and survival of Tamarixia radiata (Hymenoptera: Eulophidae), an ectoparasitoid of the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae), on hosts exposed to an entomopathogenic fungus. Journal of Economic Entomology. 109:1995-2005. doi: 10.1093/jee/tow164.
Hall, D.G., Hentz, M.G. 2016. An evaluation of plant genotypes for rearing Asian citrus psyllid (Hemiptera: Liviidae). Florida Entomologist. 99:471-480.
Paris, T.M., Allan, S.A., Hall, D.G., Hentz, M.G., Hetsey, G.G., Stansly, P.A. 2016. Host plant affects morphometric variation of Diaphorina citri (Hemiptera: Liviidae). PeerJ. Peer J 4:e2663. https://doi.org/10.7717/peerj.2663.
Paris, T.M., Allan, S.A., Hall, D.G., Hentz, M.G., Croxton, S.D., Ainpudi, N., Stansly, P.A. 2016. Effects of temperature, photoperiod, and rainfall on morphometric variation of Diaphorina citri (Hemiptera: Liviidae). Environmental Entomology. 46(1):143-158. https://doi.org/10.1093/ee/nvw161.