Monique Rivera
Cornell University, Entomology, Faculty Member
- Rutgers, The State University of New Jersey, Entomology, Graduate StudentUniversity of California, Riverside, Entomology, Faculty MemberUniversity of Florida, Entomology and Nematology, Post-Docadd
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Wind directly influences the spread of vector-borne plant pathogens by driving the passive dispersal of vectors to potentially new areas. Here, we evaluated the effect of wind speed and direction on the dispersal of the Asian citrus... more
Wind directly influences the spread of vector-borne plant pathogens by driving the passive dispersal of vectors to potentially new areas. Here, we evaluated the effect of wind speed and direction on the dispersal of the Asian citrus psyllid (ACP), Diaphorina citri (Kuwayama) (Hemiptera: Psyllidae), the vector of the bacteria causing huanglongbing (HLB), a lethal disease of citrus. The effect of different wind speeds on short or long-distance dispersal of ACP was investigated using a high-speed wind tunnel under laboratory conditions. The effect of wind direction on ACP dispersal under field conditions was evaluated using custom-made wind vane-style traps. In wind tunnel assays, ACP remained on plants until wind treatments reached ≥48 km/h when psyllids were mostly dislodged from plants and moved by the wind. For a short-distance, wind-driven movement (movement by the wind from one plant to another), the effect of wind speed was not significant at any of the wind speed treatments tes...
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Abstract Florida citrus production has declined severely due to huanglongbing (HLB; “citrus greening disease”) caused by Candidatus Liberibacter asiaticus (CLas), a phloem-limited bacterium transmitted by the Asian citrus psyllid (ACP;... more
Abstract Florida citrus production has declined severely due to huanglongbing (HLB; “citrus greening disease”) caused by Candidatus Liberibacter asiaticus (CLas), a phloem-limited bacterium transmitted by the Asian citrus psyllid (ACP; Diaphorina citri Kuwayama). Kaolin particle films are a tool used to repel insect pests and improve growth. The film covers the natural color of the leaves, which attracts ACP. Kaolin, naturally white in color, has been found to reduce ACP in citrus plantings. Previous research suggests adding a red dye might lead to further ACP reductions by reducing ultraviolet and blue light that attract ACP. We implemented a field experiment to test the effects of white and red-dyed particle films on ACP pressure, CLas infection, and citrus growth over the course of a two-year field study. In this study, white and red-dyed kaolin particle films were applied in young, non-bearing ‘Hamlin’ sweet orange (Citrus x sinensis) trees. The white and red-dyed kaolin treatments reduced ACP pressure and delayed HLB infection, and the red-dyed kaolin particle film was more effective in reducing ACP and in delaying CLas infection. Trees in both the white and red kaolin treatments had greater relative growth rate of trunk cross-sectional area (TCSA) than controls. This effect was observed regardless of CLas infection. Both particle film treatments resulted in greater final TCSA. Our results suggest particle films are an effective alternative to insecticide-based management of ACP and have the added benefit of increasing citrus tree growth under HLB pressure.
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Abstract The Argentine ant, Linepithema humile, is an invasive ant species well established throughout subtropical climates in the United States. The Argentine ant disrupts natural ecosystems by displacing native ant species and... more
Abstract The Argentine ant, Linepithema humile, is an invasive ant species well established throughout subtropical climates in the United States. The Argentine ant disrupts natural ecosystems by displacing native ant species and associating with phloem-feeding insects, which they protect from natural enemies in exchange for honeydew excreted by the phloem-feeders. Thus, interactions between these ants and phloem-feeders can be an issue of critical importance in agroecosystems. In this study, we aimed to determine whether the presence or absence of another invasive pest, Asian Citrus psyllid (ACP), Diaphorina citri, adjacent habitat types, and edge complexity impact the species richness, activity, and distribution of ants including the Argentine ant within citrus groves in southern California. When ACP were present and edge complexity was higher, ant activity rates were higher, yet we observed a decline in total ant species richness. Surrounding habitat type had no effect on ant activity or total ant species richness. Understanding the spatial patterns of both the Argentine ant and ACP can aid future management practices for controlling both Argentine ants and Asian citrus psyllid populations.
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Additional file 1: S1 Fig. Proposed models of SA-dependent immune responses in C. sinensis. The figure was created and designed by the authors.
The Asian citrus psyllid (ACP) Diaphorina citri (Hemiptera:Liviidae), vector of huanglongbing disease, displays a high degree of color polyphenism. In the adult stage, ACP exhibits abdominal colors that can be separated into three color... more
The Asian citrus psyllid (ACP) Diaphorina citri (Hemiptera:Liviidae), vector of huanglongbing disease, displays a high degree of color polyphenism. In the adult stage, ACP exhibits abdominal colors that can be separated into three color groupings: blue-green, grey-brown and orange-yellow. Color morphology has been shown to influence important and energetically costly psyllid life traits including reproduction, dispersion, immune defense and resistance to insecticides. Despite this, it remains unclear how color morphology is correlated with feeding behavior. Understanding variation in feeding behavior of the ACP color morphs is critical to better understanding how ACP populations utilize host-plants and to assess potential risk for transmission of the causal agent of huanglongbing disease. We compared the feeding behavior of the three ACP color morphs by using electropenetrography (EPG). We did not detect differences in the feeding behavior activities at phloem or xylem tissues when ...
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The Asian citrus psyllid, Diaphorina citri, is the vector of the pathogenic bacteria that causes Huanglongbing, the most devasting disease affecting citrus worldwide. As cultivation of citrus tends to expand northward, the tolerance of... more
The Asian citrus psyllid, Diaphorina citri, is the vector of the pathogenic bacteria that causes Huanglongbing, the most devasting disease affecting citrus worldwide. As cultivation of citrus tends to expand northward, the tolerance of psyllids to freezing temperatures needs to be investigated. While mortality of D. citri to cold temperature has been previously studied, much less is known regarding the acclimation potential of psyllids to cold temperatures. We first evaluated cold resistance of D. citri depending on color morph and sex. Subsequently, we compared mortality of D. citri at −4 °C for 10 hours between unacclimated psyllids, psyllids that were gradually acclimated to cold over 1 or 2 weeks, and psyllids intermittently acclimated also for 1 or 2 weeks. We did not find major differences in cold resistance between color morphs and sex. We found that after 1 week of gradual acclimation, the survival of psyllids at −4 °C increased to 86%, compared to 20% in the control group. Survival did not increase after the second week of gradual acclimation. Although intermittent acclimation improved survival compared to the control group, it was less effective than gradual acclimation with a survival at 30% and 70% after 1 and 2 weeks of acclimation, respectively, although this difference with gradual acclimation was not significant at week 2. These data show that gradual cold acclimation allows D. citri to survive brief periods below freezing. It may serve as a mechanism responsible for increasing northern establishment of this pest.
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Diaphorina citri Kuwayama (Hemiptera: Liviidae), commonly known as Asian citrus psyllid (ACP), is an invasive insect pest and the vector of the bacterium causing Huanglongbing (HLB), a lethal disease of citrus. In the United States, ACP... more
Diaphorina citri Kuwayama (Hemiptera: Liviidae), commonly known as Asian citrus psyllid (ACP), is an invasive insect pest and the vector of the bacterium causing Huanglongbing (HLB), a lethal disease of citrus. In the United States, ACP has been established in all citrus-producing zones, all of which have different environmental conditions. The spread of ACP and, more importantly, HLB, has progressed differently depending on the state, with more rapid spread in Florida and Texas than in California. Climatic variations between the regions are likely a strong factor in the difference in the rate of spread. Despite this, it is unknown how the flight capacity of D. citri is influenced by high temperatures (>30 °C) and subsequently, low humidity experienced in California but not in Texas or Florida. In this study, by using a custom-made, temperature-controlled flight mill arena, we assessed the effect of high temperatures on the flight capacity and flight propensity of D. citri under ...
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Research Interests: Horticulture and Biology
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Insects use a range of cues to help them interact with each other and their host plants. Among these cues, olfaction plays a major role in host selection. The present study investigated the behavioral response of the brown marmorated... more
Insects use a range of cues to help them interact with each other and their host plants. Among these cues, olfaction plays a major role in host selection. The present study investigated the behavioral response of the brown marmorated stink bug, Halyomorpha halys (Stål), and its egg parasitoid, Trissolcus japonicus (Ashmead), to host plant-related odors. We used H. halys nymphs since their response to host odors is relatively unknown. In a Y-tube, we first evaluated the behavioral response of H. halys nymphs to whole-fruit odors of apple [Malus domestica (Borkh.)] and peach [Prunus persica (L.) Batsch)]. Subsequently, we tested the behavioral response of H. halys and T. japonicus to 18 selected synthetic volatiles previously identified from H. halys and its common host plants. In the greenhouse, we further tested H. halys attraction to the most promising of these volatiles individually and as blends. In single-choice tests, H. halys nymphs preferred odors from apple and peach over th...
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Plant immunity against pathogens and pests is comprised of complex mechanisms orchestrated by signaling pathways regulated by plant hormones [Salicylic acid (SA) and Jasmonic acid (JA)]. Investigations of plant immune response to... more
Plant immunity against pathogens and pests is comprised of complex mechanisms orchestrated by signaling pathways regulated by plant hormones [Salicylic acid (SA) and Jasmonic acid (JA)]. Investigations of plant immune response to phytopathogens and phloem-feeders have revealed that SA plays a critical role in reprogramming of the activity and/or localization of transcriptional regulators via post-translational modifications. We explored the contributing effects of herbivory by a phytopathogen vector [Asian citrus psyllid, Diaphorina citri] and pathogen [Candidatus Liberibacter asiaticus (CLas)] infection on response of sweet orange [Citrus sinensis (L.) Osbeck] using manipulative treatments designed to mimic the types of infestations/infections that citrus growers experience when cultivating citrus in the face of Huanglongbing (HLB) disease. A one-time (7 d) inoculation access period with CLas-infected vectors caused SA-associated upregulation of PR-1, stimulating defense response a...
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Phytophagous insects, including Asian citrus psyllids (Diaphorina citri Kuwayama), use multiple sensory modalities (vision, olfaction, and gustation,) to locate and accept host plants. We explored incorporation of several sensory cues... more
Phytophagous insects, including Asian citrus psyllids (Diaphorina citri Kuwayama), use multiple sensory modalities (vision, olfaction, and gustation,) to locate and accept host plants. We explored incorporation of several sensory cues into a multi-modal attract-and-kill device (AK device) using a three-dimensional shape to increase visibility, as well as elements of color, attractant, phagostimulant, UV reflectant, and toxicant. Attraction of adult D. citri to the device was mediated by a combination of a highly reflective yellow cylinder, a UV reflectant compound (magnesium oxide), and an odorant blend as a short-range attractant. The device surface was coated with a slow-release wax matrix (SPLAT™) augmented with a phagostimulant consisting of a 3-component blend (formic acid, acetic acid, and para-cymene) and an insecticide (β-cyfluthrin). Psyllids landing on the device attempted to feed from the wax matrix, became intoxicated, died, and fell from the device. The device remained ...
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Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae and Platypodinae) bore into tree xylem to complete their life cycle, feeding on symbiotic fungi. Ambrosia beetles are a threat to avocado where they have been found to vector a... more
Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae and Platypodinae) bore into tree xylem to complete their life cycle, feeding on symbiotic fungi. Ambrosia beetles are a threat to avocado where they have been found to vector a symbiotic fungus, Raffaelea lauricola, the causal agent of the laurel wilt disease. We assessed the repellency of methyl salicylate and verbenone to two putative laurel wilt vectors in avocado, Xyleborus volvulus (Fabricius) and Xyleborus bispinatus (Eichhoff), under laboratory conditions. Then, we tested the same two chemicals released from SPLAT flowable matrix with and without low-dose ethanol dispensers for manipulation of ambrosia beetle populations occurring in commercial avocado. The potential active space of repellents was assessed by quantifying beetle catch on traps placed ‘close’ (~5–10 cm) and ‘far’ (~1–1.5 m) away from repellent dispensers. Ambrosia beetles collected on traps associated with all in-field treatments were identified to species...
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Recent work has shown the potential for enhanced efficacy of entomopathogenic nematodes (EPN) through their attraction to herbivore induced plant volatiles. However, there has been little investigation into the utilization of these... more
Recent work has shown the potential for enhanced efficacy of entomopathogenic nematodes (EPN) through their attraction to herbivore induced plant volatiles. However, there has been little investigation into the utilization of these attractants in systems other than in those in which they were identified. We compared (E)-β-caryophyllene and pregeijerene in the highbush blueberry (Vaccinium corymbosum) agroecosystem in their ability to enhance the attraction of EPN to and efficacy against the system's herbivore, oriental beetle (Anomala orientalis). The relative attractiveness of (E)-β-caryophyllene and pregeijerene to a local isolate of the EPN species Steinernema glaseri was tested in a six-arm olfactometer in the laboratory to gather baseline values of attraction to the chemicals alone in sand substrate before field tests. A similar arrangement was used in a V. corymbosum field by placing six cages with assigned treatments and insect larvae with and without compound into the so...
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OF THE DISSERTATION ........................................................................... ii! Acknowledgements ............................................................................................................ iv!... more
OF THE DISSERTATION ........................................................................... ii! Acknowledgements ............................................................................................................ iv! Dedication ........................................................................................................................... v! List of Tables by Chapter ................................................................................................... ix! List of Figures by Chapter .................................................................................................. x! Introduction ......................................................................................................................... 1! Entomopathogenic Nematodes ....................................................................................... 4! The Highbush Blueberry (Vaccinium corymbosum) System in the Pinelands National Reserve and Oriental Beetle, Anomal...
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The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is the vector of the bacterium responsible for huanglongbing, a deadly plant disease affecting citrus worldwide. We investigated the effects of wind direction and... more
The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is the vector of the bacterium responsible for huanglongbing, a deadly plant disease affecting citrus worldwide. We investigated the effects of wind direction and speed on flight duration and direction of D. citri, as well as the effects of temperature and barometric pressure on sustained flight duration of D. citri. Experiments were performed with laboratory flight mills and wind tunnels. Flight activity of D. citri increased with increasing temperature. Of the few insects that flew at 18°C, most performed short duration flights (<60 s). When exposed to temperatures between 21 and 28°C, D. citri performed long duration flights (>60 s). In addition, the distance covered increased with temperature. Interestingly, males were more sensitive to cold temperature and flew significantly shorter distances than females at 21 and 25°C. Barometric pressure recorded before and during the flight mill experiment sugg...
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The tobacco splitworm (Potato tuberworm, Phthorimaea operculella), a microlepidopteran with oligophagous larvae that feed on solanaceous plants, is a recent concern for tobacco growers. Tobacco (Nicotiana tabacum) is an infrequent host of... more
The tobacco splitworm (Potato tuberworm, Phthorimaea operculella), a microlepidopteran with oligophagous larvae that feed on solanaceous plants, is a recent concern for tobacco growers. Tobacco (Nicotiana tabacum) is an infrequent host of this species and few studies are available on the biology and ecology of this pest in the tobacco agroecosystem. Potato (Solanum tuberosum) is the most common host of P. operculella on which larvae both mine leaves and bore in tubers. In tobacco, larvae primarily act as leaf-miners. As observed through correlation of pheromone trap captures with in-field damage in tobacco from 2008-10, splitworms are a multivoltine pest (2-3 generation per field/season) with potential to cause economic loss at a high rate of infestation during the late season. When feeding on tobacco, the chemical and physical differences within the plant as well as the cultural practice of priming in flue-cured varieties of tobacco may impact the establishment and performance of s...
Entomopathogenic nematodes (EPNs) are potentially viable biocontrol agents of root pests in agricultural crops. Recent studies in maize and citrus have shown the ability of EPNs to utilize herbivore-induced responses from plant roots to... more
Entomopathogenic nematodes (EPNs) are potentially viable biocontrol agents of root pests in agricultural crops. Recent studies in maize and citrus have shown the ability of EPNs to utilize herbivore-induced responses from plant roots to locate insect hosts belowground; however, thus far no studies have considered natural habitats. In New Jersey's Pinelands National Reserve (PNR), natural populations of highbush blueberry (Vaccinium corymbosum) and lowbush blueberry (Vaccinium angustifolium) from which most popular highbush blueberry varieties were domesticated are commonly found adjacent to commercial blueberry fields. Oriental beetle (Anomala orientalis) is an invasive, prevalent root-feeding pest for which blueberry growers often use soil-applied chemicals for control. We compared differences in species infectivity and diversity of EPNs between natural and agricultural blueberry habitats to build an initial framework for studying the effects of plant domestication on belowgrou...
Recent studies in the maize and citrus systems have shown the ability of entomopathogenic nematodes (EPNs) to utilize herbivore-induced responses from plant roots for location insect hosts belowground. However, thus far no studies have... more
Recent studies in the maize and citrus systems have shown the ability of entomopathogenic nematodes (EPNs) to utilize herbivore-induced responses from plant roots for location insect hosts belowground. However, thus far no studies have considered natural habitats. The highbush blueberry (Vaccinium corymbosum) is both a commercial small fruit commodity and native to North America. In New Jersey's Pinelands National Reserve (PNR), the natural populations of highbush blueberry (Vaccinium corymbosum) and lowbush blueberry (Vaccinium angustifolium) from which most popular highbush blueberry varieties were domesticated are commonly found adjacent to commercial blueberry fields. In this agroecosystem, EPNs could be useful in managing larval feeding of the oriental beetle (Anomala orientalis), a root-feeding, invasive pest. We investigated the effects of plant domestication on the EPN community. Soil was sampled and plants were propagated from 5-10 pairs of domesticated and wild blueber...
Agricultural fields now constitute an important habitat for insects. The overwhelming majority of these fields are composed of domesticated crops subject to deliberate breeding programs. Traditionally, such programs have emphasized things... more
Agricultural fields now constitute an important habitat for insects. The overwhelming majority of these fields are composed of domesticated crops subject to deliberate breeding programs. Traditionally, such programs have emphasized things like yield, fruit size, flavor, and color. However, researchers have only begun to explore the other consequences of domestication. For example, have breeding programs changed crop plants' defenses against herbivory? If so, this could affect the composition of arthropod communities that form around these plants. In this study, I assess differences between communities on wild and domesticated highbush blueberry, Vaccinium corymbosum. I sampled arthropods on adjacent wild and cultivated populations of V. corymbosum at ten different sites in the Pinelands region of southern New Jersey throughout summer 2013. I compare wild and cultivated samples for species present, diversity, evenness, and abundance.
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ABSTRACT The distribution of insect herbivores within their hosts can be influenced by insect preference, plant characteristics, and biotic interactions such as refuge from predation. We observed significantly more Phthorimaea operculella... more
ABSTRACT The distribution of insect herbivores within their hosts can be influenced by insect preference, plant characteristics, and biotic interactions such as refuge from predation. We observed significantly more Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) larvae in the lower portion of commercial tobacco plants, Nicotiana tabacum L. (Solanaceae), an occasional host, and sought to explain this distribution pattern. Phthorimaea operculella are oligophagous leaf miners of solanaceous plants, including cultivated crops. Females lay their eggs in the soil beneath N. tabacum plants rather than on the foliage, forcing newly hatched larvae to search for host tissue. We hypothesized that P. operculella larvae were establishing in the lower portion of N. tabacum plants because either they gained a performance advantage, or it was the first suitable leaf material contacted. To measure within-plant larval performance, neonates were released in cages on leaves in the upper, middle, and lower stalk positions of the plant before and after the plant flowered. Phthorimaea operculella performed significantly better on younger plants and in the top leaves. To test larval ability to move within and between plants, we removed leaves at four heights to increase the distance newly hatched larvae must travel. Larval establishment was highest on plants with no leaves removed, but larvae were able to move an average distance of over 70 cm from release point to host leaves in plants directly above the release point and adjacent plants. Phthorimaea operculella larvae appear to utilize suboptimal N. tabacum host tissue to maximize their chances of survival.