Trevor Williams

Trevor Williams
Instituto de Ecología AC (INECOL) · Manejo Biorracional de Plagas y Vectores

PhD Imperial College (University of London)

About

263
Publications
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Introduction
I work in the department of Manejo Biorracional de Plagas y Vectores, Instituto de Ecología AC (INECOL), Xalapa, Mexico. I mainly work on: -- Insect virus ecology (baculoviruses and iridoviruses); -- Biological insecticides; -- Mosquito control (mainly using spinosad). Articles that are not available on ResearchGate may be available on my website www.trevorwilliams.info, or send me request.

Publications

Publications (263)
Article
50 day access free at: https://authors.elsevier.com/a/1fX8d3kk-aPdH8 Previous studies report that the pathogenicity of nucleopolyhedrovirus occlusion bodies (OBs) is reduced if OBs are collected from living infected insects compared to virus-killed insects. We compared the production and characteristics of SfMNPV OBs collected from living and viru...
Article
Acid hydrolyzed proteins with borax and torula yeast pellets are attractants commonly used for monitoring the West Indian fruit fly, Anastrepha obliqua (Macquart). Alkaline hydrolysis of proteins has been poorly studied as a source of attractants for tephritids, despite it increasing the production of ammonia, a known attractant for A. obliqua and...
Article
Full-text available
Sterile males of Aedes aegypti were released once a week for 8 weeks to evaluate the dispersal ef-ficiency of ground and aerial drone release methods in a rural village of 26 Ha in southern Mexico. Indoor and outdoor BG-Sentinel traps were placed in 13–16 houses distributed throughout the village. The BG traps were activated 48 h after the release...
Article
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Helicoverpa armigera single nucleopolyhedrovirus (HearSNPV) is a virulent pathogen of lepidopterans in the genera Heliothis and Helicoverpa, whereas Helicoverpa armigera multiple nu-cleopolyhedrovirus (HearSNPV) is a different virus species with a broader host range. This study aimed to examine the consequences of coocclusion of HearSNPV and HearMN...
Article
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Nucleopolyhedroviruses (NPV, Baculoviridae ) that infect lepidopteran pests have an established record as safe and effective biological insecticides. Here, we describe a new approach for the development of NPV-based insecticides. This technology takes advantage of the unique way in which these viruses are transmitted as collective infectious units,...
Article
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Ammonia is considered a key component in the attraction of tephritid flies to protein-based lures. The addition of ammonium acetate to improve hydrolyzed protein-borax mixtures used to monitor tephritids has not been evaluated, although it has improved attraction to toxic baits. The presence of ammonium acetate crystals in a ventilated tube inside...
Article
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The mechanisms generating variability in viruses are diverse. Variability allows baculovi-ruses to evolve with their host and with changes in their environment. We examined the role of one genetic variant of Chrysodeixis includens nucleopolyhedrovirus (ChinNPV) and its contribution to the variability of the virus under laboratory conditions. A mixt...
Article
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Enhancins are metalloproteinases that facilitate baculovirus infection in the insect midgut. They are more prevalent in granuloviruses (GVs), constituting up to 5% of the proteins of viral occlusion bodies (OBs). In nucleopolyhedroviruses (NPVs), in contrast, they are present in the envelope of the occlusion-derived virions (ODV). In the present st...
Article
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Tephritid fly responses to food-based attractants involve a complex range of food-derived semiochemicals, including ammonia. We performed laboratory and field experiments to compare the attraction of Anastrepha obliqua (Macquart) to ammonia with the attraction to commercial food attractants and torula yeast at a range of pHs. A positive correlation...
Article
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The sterile insect technique may prove useful for the suppression of mosquito vectors of medical importance in regions where arboviruses pose a serious public health threat. In the present study, we examined the effects of sterilizing irradiation doses across different ratios of fertile:irradiated males on the mating competitiveness of Ae. aegypti...
Article
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Tephritid fruit flies are susceptible to insecticide treatments when leaving infested fruit to pupate in the soil and when emerging as adults. Laboratory experiments involved placing third instar larvae of the Mexican fruit fly, Anastrepha ludens on sand treated with the naturally-derived insecticide spinosad (SpinTor 12SC). Negative correlations w...
Article
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Alphabaculoviruses (Baculoviridae) are pathogenic DNA viruses of Lepidoptera that have applications as the basis for biological insecticides and expression vectors in biotechnological processes. These viruses have a characteristic physical structure that facilitates the transmission of groups of genomes. We demonstrate that coinfection of a suscept...
Article
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Abstract: Indoor and outdoor ovitraps were placed in 15 randomly selected houses in two rural villages in Chiapas, southern Mexico. In addition, ovitraps were placed in five transects surrounding each village, with three traps per transect, one at the edge, one at 50 m, and another at 100 m from the edge of the village. All traps were inspected wee...
Article
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The mode of action underlying the insecticidal activity of the Bacillus thuringiensis (Bt) binary pesticidal protein Vpa1/Vpa2 is uncertain. In this study, three recombinant baculoviruses were constructed using Bac-to-Bac technology to express Vpa2Ac1 and two novel Vpa2-like genes, Vpa2-like1 and Vpa2-like2, under the baculovirus p10 promoter in tr...
Article
Online access: https://authors.elsevier.com/c/1bbjA3kk-aJ9Mq The presence of contaminant microbes in baculovirus-based insecticides is regulated by phytosanitary product registration authorities. We aimed to determine whether the abundance of microbes in suspensions of Spodoptera exigua multiple nucleopolyhedrovirus occlusion bodies (OBs) could be...
Article
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Due to its availability and low cost, apple cider vinegar (ACV) is a frequently used as an attractant for monitoring the invasive spotted wing drosophila, Drosophila suzukii. In laboratory cage experiments, the attraction of ACV alone was compared with ACV in mixtures with different concentrations of acetic acid, propionic acid, different hydrolyze...
Article
Abstract. Colony collapse disorder of honey bees, Apis mellifera L., is a global problem with no conclusive cause yet accepted. A previous U.S. Army study identified a DNA virus, invertebrate iridescent virus (IIV-6), and two microsporian pathogens, Nosema apis Zander 1909 and Nosema ceranae Fries et al. 1996, in bee samples from a collapsing hive....
Article
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Objective: To compare the efficacy of three modern larvicides with the organophosphate temephos for control of Aedes aegypti in water tanks in Chiapas. Materials and methods: Trials were performed to compare the efficacy of pyriproxyfen, novaluron, two formulations of spinosad (granules and tablets) and temephos in oviposition traps and domestic...
Article
Zaprionus indianus Gupta (Diptera: Drosophilidae) is a successful invasive drosophilid that is currently impacting fig production in Mexico and Brazil. Very few studies have examined the improvement of trapping strategies for this pest. Here, we compared visual responses of Z. indianus to different colors and olfactory cues. Orange and brown colore...
Article
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Bacillus thuringiensis ser. israelensis (Bti) has been widely used as microbial larvicide for the control of many species of mosquitoes and blackflies. The larvicidal activity of Bti resides in Cry and Cyt δ-endotoxins present in the parasporal crystal of this pathogen. The insecticidal activity of the crystal is higher than the activities of the i...
Article
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Naturally occurring covert infections in lepidopteran populations can involve multiple viruses with potentially different transmission strategies. In this study, we characterized covert infection by two RNA viruses, Spodoptera exigua iflavirus 1 (SeIV-1) and Spodoptera exigua iflavirus 2 (SeIV-2) (family Iflaviridae) that naturally infect populatio...
Article
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Bacillus thuringiensis (Bt)-based biological insecticides are used extensively to control insect pests and vectors of human diseases. Bt-based products provide greater specificity and biosafety than broad-spectrum synthetic insecticides. The biological activity of this bacterium resides in spores and crystals comprising complex mixtures of toxic pr...
Article
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The soil is the most important environmental reservoir for nucleopolyhedrovirus occlusion bodies (OBs). We employed a diet + soil bioassay technique to demonstrate that the earthworm Amynthas gracilus was capable of vertical transport of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) occlusion bodies (OBs) under field conditions. Incu...
Technical Report
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The original report: https://talk.ictvonline.org/ictv-reports/ictv_online_report/dsdna-viruses/w/iridoviridae SUMMARY: Members of the family Iridoviridae comprise a collection of large icosahedral, double-stranded DNA (dsDNA)-containing viruses that are classified into two subfamilies: Alphairidovirinae and Betairidovirinae (Table 1.Iridoviridae)....
Article
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The present study examined the efficacy of λ-cyhalothrin, pyriproxyfen and granular formulations of spinosad and temephos for the control of mosquito larvae present in experimental tires in Veracruz State, Mexico in the period 2015-2016. Both λ-cyhalothrin and spinosad granules provided control of larvae and pupae of Aedes aegypti, Ae. albopictus a...
Article
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Specific ecological interactions between insects and microbes have potential in the development of targeted pest monitoring or control techniques for the spotted wing drosophilid, Drosophila suzukii (Matsumura), an exotic invasive pest of soft fruit. To evaluate D. suzukii attraction to yeast species from preferred types of fruit, three yeasts were...
Article
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Phylogenetic analyses suggest that Mamestra brassicae multiple nucleopolyhedrovirus (MbMNPV) and Helicoverpa armigera multiple nucleopolyhedrovirus (HearMNPV) may be strains of the same virus species. Most of the studies comparing their biological activities have been performed in their homologous hosts. A comparison of host range and stability in...
Article
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Genetic variation in baculoviruses is recognized as a key factor, not only due to the influence of such variation on pathogen transmission and virulence traits, but also because genetic variants can form the basis for novel biological insecticides. In this study, we examined the genetic variability of Chrysodeixis includens nucleopolyhedrovirus (Ch...
Article
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Several commercial products and home-made attractants have been developed for monitoring and mass-trapping of the spotted wing drosophila, Drosophila suzukii. Growers in Mexico have adopted an attractant based on a fermenting mixture of raspberry pulp and sucrose, with anecdotally promising results. We compared the capture rates of traps baited wit...
Article
The inefficient production of nucleopolyhedrovirus occlusion bodies (OBs) can limit the commercialization of virus-based insecticides. The production of OBs in SfMNPV-infected Spodoptera frugiperda fourth instars was compared among groups of larvae that were frozen (−20 °C) immediately following death, or subjected to a 9-day period of post-mortem...
Article
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The sterile insect technique (SIT) may offer a means to control the transmission of mosquito borne diseases. SIT involves the release of male insects that have been sterilized by exposure to ionizing radiation. We determined the effects of different doses of radiation on the survival and reproductive capacity of local strains of Aedes aegypti and A...
Data
Original data from all studies. (XLSX)
Article
Full-text available
Polyols are commonly used in food and medicines as sweeteners and preservatives but may also have insecticidal properties against some species of Diptera. Here we compared the insecticidal activity and feeding response of glycerol and propylene glycol (PG) on two tephritids: Anastrepha ludens and Anastrepha obliqua, and the drosophilid Drosophila s...
Article
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Quantitative laboratory bioassay methods are required to evaluate the toxicity of novel insecticidal compounds for pest control and to determine the presence of resistance traits. We used a radioactive tracer based on 32 P-ATP to estimate the volume of a droplet ingested by two dipteran pests: Ceratitis capitata (Tephritidae) and Drosophila suzukii...
Data
Calibration curve for quantification of ingested volume in (A) Ceratitis capitata and (B) Drosophila suzukii. (DOCX)
Data
Changes in 50% lethal concentration (LC50, blue points) and 90% lethal concentration (LC90, orange points) values at different intervals (0.5–7 days) following ingestion of spinosad by Ceratitis capitata adults, as reported by Adan et al. [18]. (DOCX)
Data
An Excel file comprising five worksheets with raw data. (XLSX)
Article
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Neff alleges that evaluations of scientist performance by Mexico's National System of Researchers (SNI) undermine the utility of science in Mexico. Using information from interviews with Mexican ecologists, he suggests that evaluations that use journal impact factor (IF) as a proxy for quality is flawed and relinquish control of science policy to d...
Article
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In 1999, Anticarsia gemmatalis nucleopolyhedrovirus (AgMNPV) was introduced into a major soybean-growing region in Tamaulipas, Mexico, for control of its lepidopteran host, Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae). The virus introduction proved to be highly successful in controlling this agronomically important pest. In order to determ...
Article
The larval developmental environment can affect the quality of artificially reared insects used in pest control programs that apply the sterile insect technique. We used a liquid larval diet lacking corncob fractions (an ingredient which may be contaminated by toxins that inhibit larval development and drastically reduce insect production in mass-r...
Article
The Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) is the basis for viral insecticides in several countries in Latin America. The rate of acquisition of infection and the transmission of the pathogen from infected to healthy conspecifics both influence the efficacy of virus insecticides. By comparing the leaf area consumed by larvae w...
Article
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Background: A Chrysodeixis chalcites nucleopolyhedrovirus from the Canary Islands (ChchNPV-TF1) has proved to be effective for control of this pest on banana crops. Commercialization of this virus as a bioinsecticide requires an efficient production system. Results: The most suitable larval instar for virus production was the sixth instar (L6 ),...
Article
Chrysodeixis chalcites is an emergent pest in bananas (Musa acuminata Colla) grown on the Canary Islands. Feeding damage to leaves and fruit and the control measures targeted at this pest were evaluated over a two-year period (2013-2014). The prevalence of infestations (42-100%) on the islands was similar during the two years of the study. Mean fol...
Article
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Many countries in Latin America have recently experienced outbreaks of Zika and chikungunya fever, in additional to the usual burden imposed by dengue, all of which are transmitted by Aedes aegypti in this region. To identify potential larvicides, we determined the toxicity of eight modern insecticides to A. aegypti larvae from a colony that origin...
Article
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The influence of maternal defense against natural enemies, maternal provisioning and ovi-position site selection on offspring survival before and after hatching were examined in a semelparous pentatomid bug, Ramosiana insignis. Oviposition occurs on leaves of Schoep-fia schreberi, or surrounding vegetation from which nymphs migrate to feed exclusiv...
Article
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Spinosad is recommended for Spodoptera frugiperda (J.E. Smith) larvae control; its application with phagostimulants may reduce the quantity of active ingredient required for effective pest control. Spinosad (Tracer(®) ) was formulated in maize flour matrix granules and three field tests compared 10-100 ppm a.i. granules (equivalent to 0.24 - 2.4 g...
Chapter
Full-text available
The most commonly studied invertebrate viruses are those that frequently cause overt disease in their hosts. The chapter presents many of the examples that involve insect pests of crops or forests that have been studied in the search for effective biological control agents. As most of our understanding of invertebrate virus ecology comes from bacul...
Article
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Hydrolyzed protein lures are widely used to monitor fruit fly pests but are rapidly degraded by microbial activity and must be replaced frequently. To improve the stability of lures, the quaternary ammonium biocide, benzalkonium chloride (BC), was evaluated in mixtures with two hydrolyzed proteins commonly used to monitor Anastrepha spp. The mean n...
Article
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The improvement of trap-lure combinations is an important part of integrated pest management programs that involve monitoring pests for timely insecticide applications, or for their use in control strategies such as mass trapping or bait stations. In this study improvements in the capture of Drosophila suzukii were not observed following the inclus...
Article
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Aedes aegypti is a major vector of arboviruses that may be controlled on an area-wide basis using the sterile insect technique (SIT). Larval diet is a major factor in mass-rearing for SIT programs. We compared dietary effects on immature development and adult fitness-related characteristics for an International Atomic Energy Agency (IAEA) diet, dev...
Data
Original data from all experiments. (XLSX)
Article
Full-text available
Chrysodeixis chalcites, an important pest of banana crops on the Canary Islands, is usually controlled by chemical insecticides. The present study aimed to evaluate the efficacy of the most prevalent isolate of the Chrysodeixis chalcites nucleopolyhedrovirus (ChchNPV, Baculoviridae) as a biological insecticide. Overall the prevalence of ChchNPV inf...
Data
Fuentes EG Letter. A letter written by the relevant author, Fuentes EG, which supported personal communications. (PDF)
Data
Original data. An excel file that included all the original data from all the experiments. (XLSX)
Article
Full-text available
Baculoviruses (Baculoviridae) are occluded DNA viruses that are lethal pathogens of the larval stages of some lepidopterans, mosquitoes, and sawflies (phytophagous Hymenoptera). These viruses have been developed as biological insecticides for control of insect pests and as expression vectors in biotechnological applications. Natural and laboratory...
Article
In this review we provide an overview of the diversity of large DNA viruses known to be pathogenic for invertebrates. We present their taxonomical classification and describe the evolutionary relationships among various groups of invertebrate-infecting viruses. We also indicate the relationships of the invertebrate viruses to viruses infecting mamm...
Article
Full-text available
Following the consumption of baculovirus occlusion bodies (OBs), insects may succumb to lethal disease, but the survivors can harbour sublethal covert infections and may develop, reproduce and transmit the infection to their offspring. The use of different chemical and biological stressors was examined to determine whether they could be used to act...
Article
Full-text available
The Iridoviridae is a family of large, icosahedral viruses with double-stranded DNA genomes ranging in size from 103 to 220 kbp. Members of the subfamily Alphairidovirinae infect ectothermic vertebrates (bony fish, amphibians and reptiles), whereas members of the subfamily Betairidovirinae mainly infect insects and crustaceans. Infections can be ei...
Article
Full-text available
During an insect sampling program in alfalfa crops near Montpellier, France in 2011, Laca-nobia oleracea larvae were collected that died due to nucleopolyhedrovirus infection (LaolNPV). This virus was subjected to molecular and biological characterization. The virus was a multiple nucleocapsid NPV that showed similar restriction profiles to Mamestr...