Sean Michael Prager

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Verified

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• Ph.D.
• Professor (Associate) at University of Saskatchewan

Plant pathogens can influence the behavior and performance of insect herbivores. Studies of these associations typically focus on tripartite interactions between a plant host, a plant pathogen, and its insect vector. An unrelated herbivore or pathogen might influence such interactions. This study used a model system consisting of Tobacco mosaic vir...

The increasing demand for fresh water has forced many countries to use reclaimed wastewater for agricultural purposes. This water contains pharmaceuticals and personal care products (PPCPs) that remain biologically active following passage through wastewater treatment plants. Run-off from farms and contaminated water from treatment facilities expos...

Among the many topics of interest to ecologists studying associations between phytophagous insects and their host plants are the influence of natal host plant on future oviposition decisions and the mechanisms of generalist versus specialist host selection behavior. In this study, we examined the oviposition preferences, behavior and larval develop...

Parasitoid acceptance of host individuals that differ in suitability is dynamic, varying with physiological state and experience. Female parasitoids with high egg loads and low life expectancy (i.e. time limited) are more willing to accept hosts with low suitability for progeny development than females with low egg loads and high life expectancy (i...

Integrated pest management (IPM) is an educated and systematic effort to use multiple control techniques to reduce pest damage to economically acceptable levels while minimizing negative environmental impacts. Although its benefits are widely acknowledged, IPM is not universally practiced by farmers. Potato farming, which produces one of the most i...

Grain legumes, such as faba bean (Vicia faba L.), are crucial for protein supply and soil fertility enhancement through nitrogen fixation. However, faba bean cultivation is challenged by Lygus plant bugs (Hemiptera: Miridae), which cause significant crop damage and seed quality loss. This study aimed to evaluate Lygus preferences between faba bean...

Bean leafroll virus (BLRV; Bean leafroll virus), a single-stranded RNA virus in the genus Luteovirus, is phloem-limited and primarily transmitted by aphids in a non-propagative, persistent manner (Rashed et al., 2018; Kidanemariam and Abraham, 2023). BLRV infects various legumes and has been reported from major pulse-growing regions worldwide (Agin...

In Saskatchewan, red clover (Trifolium pratense L.) is often grown for seed production. However, there is no recognized or data supported seeding rate for seed production of red clover in Saskatchwan. The objectives of this study were to identify an optimal seeding rate for seed production and biological nitrogen fixation (BNF) and to examine their...

Cottony ash psyllid (CAP, Psyllopsis discrepans) is an important, invasive insect pest of ash trees in North America, where it has established populations and is the host of a newly identified strain of ‘ Candidatus Liberibacter solanacearum’. However, not much is known about the diversity of its introduced population. In this study, a CAP mitochon...

Aster leafhopper (Hemiptera: Cicadellidae: Macrosteles quadrilineatus Forbes) is a polyphagous insect species that migrates into the upper Midwest of the United States and the Western Canadian Prairies. Populations of this insect are associated with the transmission of a plant pathogen (Candidatus Phytoplasma asteris, 16SrI) to several annual crops...

In plant-microbe-insect systems, plant-mediated responses involve the regulation and interactions of plant defense signaling pathways of phytohormones jasmonic acid (JA), ethylene (ET), and salicylic acid (SA). Phytoplasma subgroup 16SrI is the causal agent of Aster Yellows (AY) disease and is primarily transmitted by populations of aster leafhoppe...

Pea aphid (Acyrthosiphom pisum Harris, Hemiptera: Aphididae) presents a significant economic challenge to lentil (Lens culinaris Medik.) production in the major growing region of Saskatchewan, Canada. During 2019-2020, field experiments were conducted to optimize the management tools for pea aphid control on lentils. A randomized split-plot design...

BACKGROUND Two consecutive field trials using a blend of entomopathogens in combination with a new chemistry insecticide were conducted to determine treatment effects on onion thrips (Thrips tabaci Lindeman) populations, crop damage, plant development, crop yield and impact on natural enemies. Products were tested in an onion cropping system and in...

A key question in pollination biology is that of how pollinators identify and choose foraging patches. Several approaches have been employed for this, including field studies and large greenhouse flight chambers. Most methods used to date are limited, though, by reliance on a combination of artificial flowers, large spatial scales, or lack of spati...

Aster yellows phytoplasmas (AYp) are a group of obligate parasites that infect a wide range of plant species, including crops such as canola and cereals and noncrops such as dandelion and wild mustard. In the Canadian Prairies, these microorganisms are mainly transmitted by a migratory species of leafhopper ( Macrosteles quadrilineatus Forbes). Alt...

Abstract. Carabid beetles are common inhabitants of agricultural fields where they encounter a variety of food options - including prey and weed seeds. The feeding behaviors of carabids are often influenced by the physical and chemical traits of prey and seed species, as such traits determine prey or seed species that are suitable for consumption....

Ground beetles (Coleoptera: Carabidae) are among the most prevalent biological agents in temperate agroecosystems. Numerous species function as omnivorous predators, feeding on both pests and weed seeds, yet the sensory ecology of seed perception in omnivorous carabids remains poorly understood. Here, we explore the sensory mechanisms of seed detec...

A key question in pollination biology is that of how pollinators identify and choose foraging patches. Several approaches have been employed for this, including field studies and large greenhouse flight chambers. Most methods used to date are limited, though, by reliance on a combination of artificial flowers, large spatial scales, or lack of spati...

Zebra chip disease (ZC), associated with the plant pathogenic bacterium ‘Candidatus Liberibacter solanacearum’ (psyllaurous) (CLso), is a major threat to global potato production. In addition to yield loss, CLso infection causes discoloration in the tubers, rendering them unmarketable. CLso is transmitted by the potato psyllid, Bactericera cockerel...

Over the past 20 years, ash trees (Oleaceae) in parts of the western United States of America and Canada have been subject to infestations with the psyllid Psyllopsis discrepans (Flor) (Hemiptera: Psyllidae). Infested trees show a series of symptoms, including pseudogalls, canopy loss, and in many cases, tree death. This is an expensive problem for...

Polyphagous insects are characterized by a broad diet comprising plant species from different taxonomic groups. Within these insects, migratory species are of particular interest, given that they encounter unpredictable environments, with abrupt spatial and temporal changes in plant availability and density. Aster leafhoppers (Hemiptera: Cicadellid...

‘Candidatus Liberibacter’ species are associated with severe, economically important diseases. Nearly all known species are putatively insect-transmitted, specifically by psyllids. Detection of ‘Ca. Liberibacter’ in plants is complicated by their uneven distribution in host plants and largely fastidius nature. The death of black (Fraxinus nigra) an...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Potato virus Y (PVY) and zebra chip (ZC) disease are major threats to solanaceous crop production in North America. PVY can be spread by aphid vectors and through vegetative propagation in potatoes. ZC is associated with “Candidatus Liberibacter solanacearum” (Lso), which is transmitted by the tomato/potato psyllid, Bactericera cockerelli Šulc (Hem...

Single-cut red clover (Trifolium pratense L.) is an important forage seed crop in Western Canada due to its winter hardiness and economical value. However, infestation of lesser clover leaf weevil (Hypera nigrirostris F.) can lead to drastic yield losses (over 50%). The aim of this research was to evaluate the effectiveness of insecticides deltamet...

Some plant pathogens are capable of manipulating their insect vectors and plant hosts in a way that disease transmission is enhanced. Aster leafhopper (Macrosteles quadrilineatus Forbes) (Hemiptera: Cicadellidae) is the main vector of Aster Yellows Phytoplasma (Candidatus Phytoplasma asteris) in the Canadian Prairies, which causes Aster Yellows (AY...

Due to their nutritional value and function as soil nitrogen fixers, production of pulses has been increasing markedly in the United States, notably in the dryland areas of the Northern Plains and the Pacific Northwest United States (NP&PNW). There are several insect-transmitted viruses that are prevalent and periodically injurious to pulse crops i...

Chemosensory proteins (CSPs) play important roles in chemosensation in insects, but their exact physiological functions remain elusive. In order to investigate the functions of CSPs in the oriental armyworm Mythimna separata, in the present study we explored expression patterns and binding characteristics of the CSP, MsepCSP8. The distinctive funct...

Phylogenetic tree of MsepCSP8 with 114 CSPs sequences from other insect species.

Primers used in present study.

The Ramachandran plot of MsepCSP8.

Zebra chip (ZC) disease has been a threat to the US potato industry for nearly two decades. ZC is associated with the bacteria ‘Candidatus Liberibacter solanacearum’ (Lso), which is transmitted by the potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae). ZC reduces yield and quality, due to discoloration of the tuber tissue. Symptom...

Long-term, sustainable management of zebra chip disease of potato, caused by 'Candidatus Liberibacter solanacearum' (Lso) and vectored by potato psyllids (Bactericera cockerelli Sulc [Hemiptera: Triozidae]), requires development of cultivars resistant or tolerant to infection or capable of reducing spread or both. We examined the influence that fiv...

Potato zebra chip disease (ZC), a threat to potato production in the USA, Mexico, New Zealand, and Central America, is associated with the bacterium “Candidatus Liberibacter solanacearum” (Cls) that is vectored by the potato psyllid (Bactericera cockerelli Sulc.). ZC control currently depends on insecticide applications, but sustainable control wil...

Potato psyllid (Bactericera cockerelli) is an important pest of potato, tomato and pepper. Not only could a toxin secreted by nymphs results in serious phytotoxemia in some host plants, but also over the past few years B. cockerelli was shown to transmit "Candidatus Liberibacter solanacearum", the putative bacterial pathogen of potato zebra chip (Z...

Alignment between AY601890 (3,077 bp, Thao et al., 2004) and the corresponding region in the mitogenome sequence of Bactericera cockerelli (KU501214). cob = cytochrome oxidase b, nad = NADH dehydrogenase subunits, rrnL = large ribosomal RNA subunit rrnS = small ribosomal RNA subunit. Sequence codes: yellow = protein coding genes, green = rRNA genes...

A: Codon usage of protein coding genes of Bactericera cockerelli, B: Paratrioza sinica, C: Cacopsylla coccinea, and D: Pachypsylla venusta. (DOCX)

Bckground: A robust integrated pest management (IPM) program is needed to reduce the use of insecticides in controlling Helicoverpa armigera. Therefore, a two year field study was conducted to evaluate the use of alternative control measures (biochemical use) for H. armigera relative to exclusively use of chemical insecticides. The entomopathogeni...

Potato psyllid is a pest of solanaceous plants throughout much of the western United States, including California, where it hasincreased and is now overwintering. The psyllid affects its plant hosts from direct feeding and by transmitting a plantpathogenic bacterium, Lso. Millions of dollars of damages have occurred in the U.S. potato industry, and...

Like many insects, mosquitoes, rely on endosymbionts to grow and develop. These can be acquired from the environment. We used next generation 454 pyrosequencing to discern the whole-body microbiome of the mosquito species Culex quinquefasciatus in various larval stadia and following exposure to common pharmaceutical and personal care products (PPCP...

The draft genome sequence of “ Candidatus Liberibacter solanacearum” strain RSTM from a potato psyllid ( Bactericera cockerelli ) in California is reported here. The RSTM strain has a genome size of 1,286,787 bp, a G+C content of 35.1%, 1,211 predicted open reading frames (ORFs), and 43 RNA genes.

Zebra chip, also known as ‘potato purple-top’ and ‘internal tuber browning’ is threatening potato production in Mexico, Central America, the United States, and New Zealand. The disease is caused by the phloem-limited ‘Candidatus Liberibacter solanacearum’ (Lso), for which potato psyllid, Bactericera cockerelli is the vector. Currently, ZC managemen...

Facultatively social bees allow for comparisons of social and solitary behaviour under similar environmental conditions. When such bees are polymorphic within the same population it provides a special and somewhat unusual opportunity to examine factors leading to cooperative (social) behaviours where many parameters such as environment are not vari...

The ecological theory on host plant choice by herbivores suggests that mothers should choose plants that will maximize their offspring's success. In annual host plants, physiology (and therefore host suitability) is sometimes influenced by maturity and growth stage, which may influence female choice. Potato plants were grown under greenhouse condit...

The tomato-potato psyllid Bactericera cockerelli (Sulc) (Hemiptera: Triozidae) is a pest of many solanaceous plants, including tomato (Solanum lycopersicum L.) and potato (Solanum tuberosum L.). In tomato, feeding by nymphs is associated with "psyllid yellows." B. cockerelli also vectors "Candidatus Liberibacter psyllaurous," an infectious bacteriu...

Perceived benefits of insecticidal transgenic crops include reduced usage of broad-based insecticides, and therefore lower risk to non-target organisms. Numerous studies have documented low or no direct toxicity of Bacillus thuringiensis (Bt)-derived toxins against non-target organisms, but there has been less research on (a) effects of secondary p...

Background: Potato psyllids (Bactericera cockerelli Sulc) are a pest on solanaceous crop plants, including bell peppers. Potato psyllids vector Candidatus Liberibacter psyllaurous, but bell peppers (Capsicum annum L.) do not exhibit symptoms from infection. Potato psyllids show variation in spatial patterns and host choice with cultivar and plant...

The potato psyllid, Bactericera cockerelli (Sulc), is a major concern for potato growers as it vectors the pathogen responsible for “zebra chip” disease. Current management practices of potato psyllids in commercial potato (Solanum tuberosum L.) fields are based almost exclusively on insecticide applications with as many as 6–8 applications in indi...

Choice of host individuals by parasitoids is dynamic, varying with physiological state and experience. In particular, female parasitoids with high egg loads and low life expectancy are more willing to accept low quality hosts than females with low egg loads and high life expectancy. However, studies of dynamic acceptance behavior in parasitoids hav...

1. Xylocopa virginica virginica Linnaeus is a wide-ranging species with plastic nesting behaviour that appears to represent an intermediary between solitary and social nesting species. Over 3 years, a natural population was studied with the objective of quantifying the relationship among population dynamics, climate, female nest provisioning behavi...

Development of effective management practices for insect pests relies heavily on sampling methods to accurately detect and quantify emerging populations. Herein we describe a novel method to extract and count nymphs of potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae), from leaves in commercial fields of potato, Solanum tuberosum...

The large carpenter bees nest in reeds, stems and wood. Many other Hymenoptera, including many wasps and some bees, have strong associations between the physical elements of their nests and behavior. Nests of the North American carpenter bee, Xylocopa virginica, were collected in southern Ontario. Nest architecture elements were examined with respe...

In bees, both body size and shape may show considerable variation associated with differences between females and males, among populations, and due to local environmental variation. We studied multiple parameters of body size and shape of the large carpenter bee Xylocopa virginica, to understand how body size and shape are influenced by sex, and by...

In bees, both body size and shape may show considerable variation associated with differences between females and males, among populations, and due to local environmental variation. We studied multiple parameters of body size and shape of the large carpenter bee Xylocopa virginica, to understand how body size and shape are influenced by sex, and by...

Large-scale insect collecting efforts that are facilitated by the use of pan traps result in large numbers of specimens being collected. Storage of these specimens can be problematic if space and equipment are limited. In this study, we investigated the effects of various preservatives (alcohol solutions and DMSO) on the amount and quality of DNA e...

Large carpenter bees (Hymenoptera: Apidae: Xylocopa) have traditionally been thought of as exhibiting solitary or occasionally communal colony social organization. However, studies have demonstrated more complex fonns of social behaviour in this genus. In this document, I examine elements ofbehaviour and life history in a North American species at...