The problem of bristletail Ctenolepisma longicaudatum (Zygentoma: Lepismatidae) in libraries, archives, and museums is increasing. It can cause damage to valuable and irreplaceable objects. We describe the effect of the use of insecticidal gel bait (active ingredient: indoxacarb) against C. longicaudatum popula-tions in three libraries, seven archives, and seven museums in Norway and Austria. Pest activity was mon-itored with sticky traps to evaluate the effect of bait application. Significant declines in pest populations were observed at all locations when small bait droplets were applied either systematically throughout the buildings or strategically close to suspected aggregations. In addition, bait was successfully used to pre-vent infestation in a new museum building. The cost of treatment, measured by the amount of bait and work hours spent, was low, and bait application was conducted by either the professional pest control technicians or the local integrated pest management (IPM) manager. The use of insecticidal gel bait and its secondary effects is a cost-efficient alternative for population decimation; moreover, the method has a low probability of negative health issues for employees at the treated localities or damage to the ob-jects. The application of bait is discussed in relation to its alignment with other IPM methods in libraries, archives, and museums.(c) 2023 The Authors. Published by Elsevier Masson SAS on behalf of Consiglio Nazionale delle Ricerche (CNR).This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )
BACKGROUND Cimex lectularius L. (bed bug) (Hemiptera: Cimicidae) is a serious indoor pest worldwide, and this nuisance needs to be controlled using different methods in integrated pest management (IPM). Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales: Cordycipitaceae) kills bed bugs, and insect pathogenic fungi may be utilized to control bed bugs in IPM. To increase knowledge of this methodology, forced exposure experiments were conducted with different formulations, doses, and substrates, using bed bugs in variable physiological states. RESULTS Both oil- and water-formulated fungal products showed significant improvement when conidial concentrations were raised in five steps from 0.02% to 2.0%. At low concentrations (0.02% in water) effects from substrate and application strategy were observed. Application on soft substrates (cotton and polyester) yielded significantly higher bed bug mortality rates than on harder substrates (paper, wood, and linoleum) with a final mortality of 35-63% against 8-10%. Multiple applications over time also improved B. bassiana's ability to kill bed bugs, and at low concentrations only a triple application on cotton showed 100% final mortality. Bed bug age and reproductive status significantly affected survival. Older and reproducing individuals showed higher mortality compared to newly emerged adults. Differences in feeding status also yielded differences in mortality timing, but only minor differences in final mortality rates. Egg production and hatching success were significantly reduced by some treatments. CONCLUSION B. bassiana appears to be an asset in the fight against bed bugs. Substrate, dosage, application strategy, and bed bug physiology are important factors to consider for optimal efficacy and safe indoor control with insect pathogenic fungi. This article is protected by copyright. All rights reserved.
The prevalence of bed bugs (Cimex lectularius L.) is increasing worldwide. Due to this increase, low-income housing owners and managers need an efficient method for controlling the pests without excessive resource use. The quality of pest control efforts is crucial for efficient eradication. Infestations often need to be approached using a variety of strategies through an integrated pest management (IPM) framework. Efficient eradication is often thought to be the responsibility of the pest control contractor alone. However, the purchase and supply management theory suggests that optimal solutions actually involve sound buyer-supplier relations to support the strategic aim of pest eradication. This study illustrates the positive outcomes of elevating pest management competence on the buyer's part. Further, this study outlines a large-scale purchase situation that quantifies bed bug control efforts, in addition to their outcomes. In total, 11,000 apartment units were observed in Oslo, Norway, over a period of six years. The release and implementation of a procurement officer together with a state-of-the-art pest management framework agreement quickly reversed the consistent escalation of bed bug infestations in the observed units. Observations revealed that the study yielded the most success in eradicating bed bugs by increasing both the number of visits to the infested apartment and the overall duration of control efforts. The improved control was achieved at a reduced cost per infested apartment unit, which allowed for the implementation of bed bug preventive measures and building-wide inspections. The observations made in this study have been discussed in the context of the impact of bed bugs in low-income communities, relative to the factors of pest burden, demography, socioeconomics, and the welfare system in Norway.
Bed bugs (Cimex lectulariusL.) have returned as a nuisance pest in the last 20 years. Different bed bug control measures in combination have not been thoroughly studied, although induction of multiple stressors may improve extermination. The effects of heat stress only, heat stress followed by exposure to insect pathogenic fungi, and heat stress followed by exposure to desiccant dust on starved and blood-fed bed bugs were investigated. Five days at 22 degrees C (control), 32 degrees C, 34 degrees C, or 36 degrees C (heat stress) did not cause mortality in adults. However, their starved first instar nymphs produced after heat stress suffered mortalities of 33%, 56% and 100%, respectively. Exposure to insect pathogenic fungi after heat stress increased the mortality of adults and their progeny compared to exposure to fungi without heat stress. The beneficial effects of heat stress were not observed in blood-fed bed bugs. Desiccant dust killed all nymphs within 2 days and all adults within 3 days regardless of previous heat stress, but survival time was prolonged by access to blood. This study highlights the advantage of combining different methods inpest management, and points to heat stress combined with blood deprivation as possible management elements to increase the control success.
The long-tailed silverfish Ctenolepisma longicaudatum (Lepismatidae: Zygentoma) is a nuisance problem in buildings and a major concern in museums, libraries and archives where it cause damage to historical and priceless items. We used laboratory bioassays and two field studies of infested buildings to evaluate spatial and temporal elements of a poisoned bait strategy. In both laboratory experiments and field studies, the efficiency of poisoned bait with indoxacarb as the active ingredient was significantly improved by placing many small bait droplets evenly distributed along all edges of the treated area compared to more clustered distributions. Extended duration of bait presence and removal of competing food sources improved the control effect significantly in the laboratory bioassays. Bait-treated populations also showed a significant decline in the number of eggs deposited and emergence of new nymphs. The study supports poisoned bait as an efficient and low risk approach against the long-tailed silverfish in which extended duration of bait presence, wide distribution of bait droplets in combination with sanitation was crucial for control in the infested premises.
Urban insects are continuously introduced to new areas as stowaways or contaminants of trade goods and may, if established in the recipient country, affect society on several levels. The bristletail Ctenolepisma longicaudata, an indoor nuisance pest, was recently detected in Norway and has shown a swift and nationwide upsurge. This study describes its numerical increase and spatio-temporal dispersal into all 18 counties of Norway within a period of 5 years. C. longicaudata showed a distinct 2-3-fold increase per year in measures of submitted pest samples, reported professional pest control cases, insurance claims, news coverage and court cases concerning disputes in transfer of ownership in real estate sales. The insurance claims concerning C. longicaudata are strongly dominated by buildings constructed in the last 15 years and reflect C. longicaudata's use of the urban habitat, while the 6788 pest control cases pinpoint the magnitude of the problem. The dispersal biology and societal impact of this nuisance pest is discussed in relation to other bristletail species and indoor pests in Norway. The study suggests that an increased import risk, aspects of modern construction and the environmental stability in new buildings may promote populations of C. longicaudata.
Pest management strives to be an efficient, yet healthy and environmentally safe control method, and the use of poisoned bait often fulfils these criteria. In the present study, we show that bait with indoxacarb as the active ingredient is highly efficient for controlling Ctenolepisma longicaudata (Escherich, 1905) and two of its relatives, Lepisma saccharina (Linnaeus, 1758) and Ctenolepisma calva (Ritter, 1910). Applying small bait droplets (size ~10 mg) along the walls of several types of buildings, at no more than 0.5 to 1.0 g bait per 100 m2, was a cost-efficient and safe strategy for the knockdown and eradication of C. longicaudata. During field experiments, the demography changed from an initial mixture of different stages to total dominance of early instars preceding the population collapse. Poisonous bait outcompeted mass-trapping with sticky-traps and conventional insect spray treatment for the efficient control of C. longicaudata in apartments. Different droplet densities (1 vs. 0.5/m2) and active ingredients (indoxacarb vs. clothianidin) did not have different effects in field experiments. These results show that poisoned bait is a highly relevant tool for managing C. longicaudata and potentially against other silverfish infestations.
The long-tailed silverfish (Ctenolepisma longicaudata) has recently made its appearance and demonstrated a tremendous proliferation in Norway, where it is currently considered a major indoor nuisance pest in modern buildings. To reduce the risk of human pesticide exposure, several baits with indoxacarb, clothianidin, fipronil or imidacloprid as the active ingredient were investigated to provide knowledge regarding their potential for integrated pest management solutions. Primary and secondary poisoning, as well as the durability of baits, were experimentally evaluated in bioassays. Baits with indoxacarb, clothianidin and fipronil killed more than 90% of the experimental insects (primary poisoning) when presented in competition with food. Only indoxacarb produced high mortality when dead conspecifics were consumed (secondary poisoning) and resulted in more than 75% mortality. The efficacy of baits with indoxacarb against C. longicaudata was also found to be very long. Laboratory degraded baits were consumed and induced high levels of mortality for more than a month, and field degraded baits for more than 6 months. Adults and juveniles were equally affected in the experiments. Primary and secondary toxicity in combination with long durability and effects on both life stages tested suggest that the bait has high-level potential as a safe control strategy against the long-tailed silverfish if indoxacarb is used as the active ingredient.
Sublethal heat stress may weaken bed bug infestations to potentially ease control. In the present study, experimental populations exposed to 34, 36 or 38°C for 2 or 3 weeks suffered significant mortality during exposure. Among survivors, egg production, egg hatching, moulting success and offspring proliferation decreased significantly in the subsequent 7 week recovery period at 22°C. The overall population success was negatively impacted by increasing temperature and duration of the stress. Such heat stress is inadequate as a single tool for eradication, but may be included as a low cost part of an integrated pest management protocol. Depending on the time available and infestation conditions, the success of some treatments can improve if sublethal heat is implemented prior to the onset of more conventional pest control measures.
Olfaction is the most important sensory mechanism by which many insects interact with their environment and a wind tunnel is an excellent tool to study insect chemical ecology. Insects can locate point sources in a three-dimensional environment through the sensory interaction and sophisticated behavior. The quantification of this behavior is a key element in the development of new tools for pest control and decision support. A wind tunnel with a suitable flight section with laminar air flow, visual cues for in-flight feedback and a variety of options for the application of odors can be used to measure complex behaviour which subsequently may allow the identification of attractive or repellent odors, insect flight characteristics, visual-odor interactions and interactions between attractants and odors lingering as background odors in the environment. A wind tunnel holds the advantage of studying the odor mediated behavioural repertoire of an insect in a laboratory setting. Behavioural measures in a controlled setting provide the link between the insect physiology and field application. A wind tunnel must be a flexible tool and should easily support the changes to setup and hardware to fit different research questions. The major disadvantage to the wind tunnel setup described here, is the clean odor background which necessitates special attention when developing a synthetic volatile blend for field application.
The increasing problem of bed bugs requires the development of new control strategies, and insect pathogenic fungi can contribute towards management. We used laboratory bioassays with Isaria fumosoroseus, Lecanicillium muscarium and Beauveria bassiana to evaluate their virulence to the bed bug. Only B. bassiana significantly affected bed bug survival and was dependent on dose and formulation. A 2% B. bassiana oil formulation induced horizontal transfer to elevate mortality in a 10-day arena bioassay. Temporal distribution of contagious individuals and increasing the dose from 2 to 4% did not increase mortality. Horizontal transfer mainly occurred between adults, and only partly between adults and nymphs. Bed bugs showed activity peaks during the night, and activity was increased by elevated levels of CO2. Distribution between harbourages was not affected by CO2 activation, level of infection or the bio-pesticide, and horizontal transfer was not dependent on the degree of aggregation. Movement in the arenas negatively affected horizontal transfer when the number of susceptible individuals was large. Level of infection also influenced behaviour as the bed bug movement increased with elevated disease burden. The use of fungi as a part of an integrated pest management strategy seems to be an interesting option that should be investigated further. B. bassiana kills bed bugs and can be carried to harbourages to target hidden individuals.
The common bed bug (Cimex lectularius, Hemiptera; Cimicidae) infests homes and service industries, and the number of infestations has greatly increased over the past 20 years. At present, no cost-effective control methods are available, and eradication programs are expensive and laborious. We investigated the control potential of desiccant dust in combination with CO2 as a bed bug activity stimulant. An initial experiment with two desiccant dusts was followed by arena studies with varying doses, available hiding places and the presence or absence of host signals. Finally, we conducted a field experiment with Syloid 244FP with or without CO2 gas. Syloid was superior compared to diatomaceous earth, and effective at the concentration of 1.0 g/m2 in the field experiment. The number of harborages and partial application of desiccant dust decreased mortality in the laboratory. Bed bug activation by CO2 appeared of minor importance in the arena studies, but was crucial for the eradication in the student dormitories. In fact, all 5 bed bug-infested dormitories with a combined treatment of desiccant dust and CO2 were freed of bed bugs, whereas eradication was not successful in any of the 6 dormitories with only desiccant dust treatment. The different results in the laboratory and field experiment were most likely caused by the longer activation and higher dose of CO2 used in the field experiment than the laboratory experiment. Our study showed that application of desiccant dust in combination with release of CO2 gas to mimic human presence is a promising option for bed bug control.
BACKGROUND: Bed bugs (Cimex lectularius L.) have returned as a nuisance pest worldwide. Their ability to withstand different types of environmental stress should be explored in order potentially to increase the efficiency of control methods.RESULTS: Immediate and long-term effects of exposure to temperatures from 0 to -10 degrees C for 1, 2 and 3 weeks are reported. Fifth-instar nymphs and adults were exposed to constant or fluctuating temperatures. Increased cold and extended time yielded higher mortality; nymphs were more resilient than adults at the shorter durations of exposure. At intermediate temperatures, mortality was higher at constant compared with fluctuating temperatures, whereas all individuals died after 3 weeks of exposure to -7 degrees C. The success among survivors after cold treatment was also affected in terms of reduced egg production, hatching success and the ability of fifth-instar nymphs to advance into the adult stage; however, nymphs produced after cold treatment developed normally.CONCLUSIONS: Detrimental effects of prolonged exposure to low temperatures were seen in bed bugs both during and after cold treatment. The results suggest that temperatures below -7 degrees C can be applied by laymen to control this pest in small items if available treatment time is of less concern. (C) 2016 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Adult bed bugs were exposed to the sublethal temperatures 34.0°C, 35.5°C, 37.0°C, 38.5°C, or 40.0°C for 3, 6, or 9 days. The two uppermost temperatures induced 100% mortality within 9 and 2 days, respectively, whereas 34.0°C had no observable effect. The intermediate temperatures interacted with time to induce a limited level of mortality but had distinct effects on fecundity, reflected by decreases in the number of eggs produced and hatching success. Adult fecundity remained low for up to 40 days after heat exposure, and the time until fertility was restored correlated with the temperature-sum experienced during heat exposure. Three or 6 days of parental exposure to 38.5°C significantly lowered their offspring’s feeding and moulting ability, which consequently led to a failure to continue beyond the third instar. Eggs that were deposited at 22.0°C before being exposed to 37.0°C for 3 or 6 days died, whereas eggs that were exposed to lower temperatures were not significantly affected. Eggs that were deposited during heat treatment exhibited high levels of mortality also at 34.0°C and 35.5°C. The observed negative effects of temperatures between 34.0°C and 40.0°C may be utilized in pest management, and sublethal temperature exposure ought to be further investigated as an additional tool to decimate or potentially eradicate bed bug populations. The effect of parental heat exposure on progeny demonstrates the importance of including maternal considerations when studying bed bug environmental stress reactions.
A blood-feeding system that utilizes a small amount of whole heparinized human blood in parafilm bags is described in detail, and similarities and differences between artificially fed and naturally rodent-fed bed bugs (Hemiptera: Cimicidae) are discussed. Blood with high levels of heparin (10%) was unsuitable for artificial colony rearing, whereas bed bugs fed on 1% heparinized blood and those that naturally ingested rat blood completed their lifecycle with similar stage structures over time, with no significant differences in mortality. No differences in feeding efficiency or fertility were found in a direct comparison of bed bugs maintained under each of these two treatments, but analysis of the full lifecycle revealed that artificially fed bed bugs became significantly smaller and laid fewer eggs than rodent-fed bed bugs. The level of membrane stretching regulated the number of bed bugs that fed. When the membrane was stretched to twice its length and width, 96% of bed bugs successfully fed through the parafilm. Whole heparinized blood that was stored at 6 °C for ≥ 14 days failed to retain its nutritional value and the amount of blood consumed and number of consecutive moults were significantly reduced.
A large-arena bioassay is used to examine sex differences in spatiotemporal patterns of bed bug Cimex lectularius L. behavioural responses to either a human host or CO2 gas. After release in the centre of the arena, 90% of newly-fed bed bugs move to hiding places in the corners within 24 h. They require 3 days to settle down completely in the arena, with generally low activity levels and the absence of responses to human stimuli for 5 days. After 8-9 days, persistent responses can be recorded. Sex differences are observed, in which females are more active during establishment, respond faster after feeding, expose themselves more than males during the daytime, and respond more strongly to the host signal. The number of bed bugs that rest in harbourages is found to vary significantly according to light setting and sex. Both sexes stay inside harbourages more in daylight compared with night, and males hide more than females during the daytime but not during the night. The spatial distribution of the bed bugs is also found to change with the presence of CO2, and peak aggregation around the odour source is observed after 24 min. Both male and female bed bugs move from hiding places or the border of the arena toward the centre where CO2 is released. Peak responses are always highest during the night. Bed bug behaviour and behaviour-regulating features are discussed in the context of control methods.
The bed bugs comeback as a pest has revitalized research on several aspects of its biology to improve management. Temperature can be manipulated to control bedbugs, but has so far been focused on temperature extremes with mortal outcome. The present study focuses on exposure of bedbugs to temperatures of a sub-lethal character, and point at its potential application in the struggle against this culprit. We exposed adult bed bugs for 34.0, 35.5, 37.0, 38.5 or 40 oC for 3, 6 or 9 days. 40 and 38.5 oC induced 100% mortality when exposed for extended time, whereas 34 oC had no observable negative effect on bedbugs. The sub-lethal temperatures did however interact with time to induce intermediate or low levels of mortality and had distinct effects on fertility. The number of eggs produced, the hatching rate of the eggs and the following nymphal feeding and moulting success decreased by increased temperature and prolonged exposure. The fertility remained low for up to 40 days after heat exposure, and the time until fertility restoration was strongly connected to the time and temperature exposure. Offspring originating from the populations with restored fertility also suffered from reduced ability to moult. This may indicate involvement of the ovarial transferred bacterial symbiont, Wolbachia, in the mechanism behind the observed temporary sterilization and reduced offspring survival. Finally, eggs produced by untreated populations at 22 oC were exposed for 34.0, 35.5 or 37.0 oC for 3 or 6 days to investigate egg mortality at relevant temperatures. Our study shows that raising temperatures to between 35 and 40 oC for different periods of time will influence bed bug population dynamics negatively. This may be utilized in professional pest management to worsen conditions for bed bugs to reduce infestation size and potential comeback after treatment. The role of this rather cheap measure ought to be further investigated both as a part of pest managers arsenal against bed bugs, but also as a potential tool in “do-it-yourself” eradication.
Volatiles from mouse carcasses in decay stages ranging from fresh to 33 days old were used to investigate oriented flight and landings in male and female blow flies of Calliphora vicina Robineau‐Desvoidy (Diptera: Calliphoridae). Oriented flight increased significantly from 36% towards fresh carcasses to 68%, 61% and 65% towards carcasses aged 3 days, 6 days and 9 days, respectively. Carcasses aged 20 days and 33 days were significantly less attractive, achieving 51% and 41% attraction, respectively. No differences emerged between the sexes in oriented flight, but a significant increase in female landings at the most attractive carcasses was observed. Headspace collections from the different stages of decay showed a succession in the volatile profile emitted from the carcasses and identified nine chemicals which peak in quantity in concurrence with the most attractive stages of decay. Three of these chemicals also showed dose–response effects as indicated by a significant correlation between the amount present and the proportion of flies responding. Blow flies are important pests and efficient traps are needed. The significant interaction between fly sex and carcass age highlights behavioural differences between male and female blow flies which can be exploited in blow fly trapping. Three new volatile chemicals, butylated hydroxyl toluene, 3‐hydroxy‐2‐butanone and nonanal, emitted from dead mice are suggested as potential attractants.