Design and Evaluation of a Sticky Attractant Trap for Intra-Domiciliary Surveillance of Aedes aegypti Populations in Mexico.

Surveillance consists of systematic data collection, analysis, and interpretation and is essential for planning and implementing control activities. The lack of success in the control and surveillance of the Ae. aegypti mosquito elsewhere demands the development of new accessible and effective strategies. This work aimed to develop and evaluate an adhesive lure trap for household indoor surveillance of Ae. aegypti. Based on a bibliographic review, four compounds that have significant attraction percentages for Ae. aegypti were considered. Our more effective blend was determined through preliminary bioassays using the high-throughput screening system (HITSS) and 90 × 90 cm mosquito cages. We designed a low-cost, pyramid-shaped, sticky cardboard trap to incorporate the selected blend. Semi-field 2 × 2 m cages and field tests were utilized to evaluate its effectiveness through mosquito capture percentages. In laboratory tests, blend number 2 presented an attraction percentage of 47.5 ± 4.8%; meanwhile, in semi-field cages, a 4-inch, 110 v powered fan was used to disperse the attractants, and then a similar capture percentage of 43.2 ± 4.0% was recorded. Results were recorded during the field evaluation of the at-house indoor environment and were compared with those recorded with the golden-standard BG-Sentinel trap, i.e., our prototype trapped an average of 6.0 ± 1.5 mosquitoes versus 10.0 ± 2.6. In most Latin American countries, there is a lack of formal and accessible strategies for monitoring adult populations of Ae. Aegypti; therefore, we must develop tools that reinforce entomological surveillance methods.

The Optimal Choice of Trap Type for the Recently Spreading Jewel Beetle Pests Lamprodila festiva and Agrilus sinuatus (Coleoptera, Buprestidae).

BACKGROUND: Two jewel beetle species native to Europe, the cypress jewel beetle, Lamprodila (Palmar, Ovalisia) festiva L. (Buprestidae, Coleoptera), and the sinuate pear tree borer, Agrilus sinuatus Olivier (Buprestidae, Coleoptera), are key pests of ornamental thuja and junipers and of orchard and ornamental rosaceous trees, respectively. Although chemical control measures are available, due to the beetles' small size, agility, and cryptic lifestyle at the larval stage, efficient tools for their detection and monitoring are missing. Consequently, by the time emerging jewel beetle adults are noticed, the trees are typically significantly damaged. METHODS: Thus, the aim of this study was to initiate the development of monitoring traps. Transparent, light green, and purple sticky sheets and multifunnel traps were compared in field experiments in Hungary. RESULTS: Light green and transparent sticky traps caught more L. festiva and A. sinuatus jewel beetles than non-sticky multifunnel traps, regardless of the larger size of the colored surface of the funnel traps. CONCLUSIONS: Although light green sticky sheets turned out to be optimal for both species, using transparent sheets can reduce catches of non-target insects. The key to the effectiveness of sticky traps, despite their reduced suitability for quantitative comparisons, may lie in the behavioral responses of the beetles to the optical features of the traps.

DNA degradation in Haplaxius crudus (Hemiptera: Cixiidae) and Diaphorina citri (Hemiptera: Liviidae) on yellow sticky traps in Florida.

Lethal bronzing (LB) and huanglongbing (HLB) are harmful plant diseases causing significant economic losses in Florida agriculture. Both diseases are caused by bacteria that are transmitted by Hemipteran insect vectors. Accurate detection of pathogens within insect vectors can help provide a better understanding of disease epidemiology. Monitoring of the vector of LB is done primarily using sticky traps within palm canopies. However, it is unknown how long pathogen and vector DNA remain intact under field conditions. If significant DNA degradation takes place over the course of days or weeks, there is a possibility of false negatives occurring when detecting pathogens from these surveys. This study determined how long Haplaxius crudus Van Duzee (Hemiptera: Cixiidae) and LB DNA could remain detectable on sticky traps under field conditions in Florida in winter and summer, using PCR and qPCR. Additionally, this study compared the DNA degradation of Diaphorina citri Kuwayama (Hemiptera: Liviidae) and Candidatus Liberibacter asiaticus (CLas), the causal agent of HLB. The results showed that DNA concentration and amplification rate declined as time on sticky traps increased. Degradation varied between different target genes. The amplification rate of insect genes from sticky trap samples suggests that sticky traps should be changed weekly in summer, and every 2 wk in winter for accurate H. crudus detection. Traps should be changed every 4 days for phytoplasma detection. Traps can be changed monthly for accurate D. citri and CLas detection. Based on these results, standard monitoring protocols can be implemented to more accurately detect vectors and pathogens.

Pan trapping is an effective method to trap adults of the jujube gall midge, Dasineura jujubifolia (Diptera: Cecidomyiidae).

Jujube gall midge (Dasineura jujubifolia Jiao & Bu) (Diptera: Cecidomyiidae) is an important pest in jujube (Ziziphus jujuba Mill.) orchards in Aksu, Xinjiang, China. Yellow sticky traps are the main device used for monitoring jujube gall midge adults, but their efficacy is low. Here, we compared the effectiveness of yellow sticky traps with water pan traps (are commonly used for trapping Diptera insects) to monitor jujube gall midge adults. Yellow sticky traps and pan traps were deployed for 2 consecutive years in jujube orchards in Aksu, Xinjiang, China. The midge's population dynamics as revealed by these 2 trap types were consistent, but the effectiveness of pan traps was about 5 times greater than that of the yellow sticky traps. In addition, pan traps captured fewer non-target species (e.g., parasitic wasps, lacewings, and lady beetles) than yellow sticky traps. Our study suggests that pan trap is an effective device to monitor jujube gall midge adults with minimal harm to natural enemies.

Detection of Small-Sized Insects in Sticky Trapping Images Using Spectral Residual Model and Machine Learning.

One fundamental component of Integrated pest management (IPM) is field monitoring and growers use information gathered from scouting to make an appropriate control tactics. Whitefly (Bemisia tabaci) and thrips (Frankliniella occidentalis) are two most prominent pests in greenhouses of northern China. Traditionally, growers estimate the population of these pests by counting insects caught on sticky traps, which is not only a challenging task but also an extremely time-consuming one. To alleviate this situation, this study proposed an automated detection approach to meet the need for continuous monitoring of pests in greenhouse conditions. Candidate targets were firstly located using a spectral residual model and then different color features were extracted. Ultimately, Whitefly and thrips were identified using a support vector machine classifier with an accuracy of 93.9 and 89.9%, a true positive rate of 93.1 and 80.1%, and a false positive rate of 9.9 and 12.3%, respectively. Identification performance was further tested via comparison between manual and automatic counting with a coefficient of determination, R 2, of 0.9785 and 0.9582. The results show that the proposed method can provide a comparable performance with previous handcrafted feature-based methods, furthermore, it does not require the support of high-performance hardware compare with deep learning-based method. This study demonstrates the potential of developing a vision-based identification system to facilitate rapid gathering of information pertaining to numbers of small-sized pests in greenhouse agriculture and make a reliable estimation of overall population density.

Influence of Trap Location in the Tree Canopy on Captures of Adventive Trissolcus japonicus (Hymenoptera: Scelionidae).

Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae) is an egg parasitoid of the invasive Asian pest, brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae). Also native to Asia, adventive T. japonicus populations have been detected in North America since 2014, and are currently reported from 15 U.S. states, the District of Columbia, and two Canadian provinces. Yellow sticky cards (YSC) have proven effective for monitoring the presence, seasonal abundance, and distribution of these adventive populations. Our research has utilized YSC deployed in the midcanopy of H. halys host trees, following a study in which all leaves on felled tree of heaven, Ailanthus altissima (Mill.) Swingle, were inspected for H. halys egg masses, yielding eggs parasitized by T. japonicus only from mid- and upper-canopy leaves. However, given that other investigators have captured T. japonicus using YSC deployed in the lower-canopy, and that the effect of YSC placement in trees on T. japonicus captures had not been examined, captures of T. japonicus on YSC in the mid- and lower-canopy of individual A. altissima were compared. Traps were replaced weekly for five weeks and assessed for scelionid species. In 2020 and 2021, T. japonicus represented ≥53% of all Scelionidae captured, and there was not a significant effect of YSC location in the canopy on its captures. Deploying YSC at either canopy height was effective for measuring the relative abundance of T. japonicus, but sampling from the lower canopy substantially improved the efficiency and convenience of T. japonicus surveillance.

Detection and estimation of Mastigimas anjosi (Hemiptera: Calophyidae) populations on Cedrela fissilis trees.

Mastigimas anjosi is an important pest of Cedrela fissilis in the southeastern and southern regions of Brazil. The objective of the present study was to investigate the effect of the temperature, relative humidity, rainfall and natural enemies on the flight activity of adults and the movement of M. anjosi nymphs, with two sampling methods, yellow sticky traps and direct collections on the leaves of C. fissilis trees. The sex ratio of this pest was also assessed. The number of M. anjosi individuals was negatively correlated with the minimum and maximum temperatures, with a population peak in late May and early June 2017. The numbers of individuals of this psyllid was positively correlated with the relative humidity and rainfall. Larvae and adults of Cycloneda sanguinea, Hippodamia convergens adults and Atopozelus opsimus nymphs and adults preyed upon M. anjosi adults and nymphs on C. fissilis leaves in the field. Mastigimas anjosi sex ratio was 0.46. Information about sampling methods of M. anjosi and its natural enemies is presented and can contribute to the integrated management of this pest in the field.

Developing a Phototactic Electrostatic Insect Trap Targeting Whiteflies, Leafminers, and Thrips in Greenhouses.

Our aim was to develop an electrostatic apparatus to lure and capture silverleaf whiteflies (Bemisia tabaci), vegetable leafminers (Liriomyza sativae), and western flower thrips (Frankliniella occidentalis) that invade tomato greenhouses. A double-charged dipolar electric field producer (DD-EFP) was constructed by filling water in two identical transparent soft polyvinyl chloride tubes arrayed in parallel with fixed separation, and then, inserting the probes of grounded negative and positive voltage generators into the water of the two tubes to generate negatively and positively charged waters, respectively. These charged waters electrified the outer surfaces of the opposite tubes via dielectric polarization. An electric field formed between the oppositely charged tubes. To lure these phototactic insects, the water was colored yellow using watercolor paste, then introduced into the transparent insulator tubes to construct the yellow-colored DD-EFP. This apparatus lured insects in a manner similar to commercially available yellow sticky traps. The yellow-colored DD-EFP was easily placed as a movable upright screen along the plants, such that invading pests were preferentially attracted to the trap before reaching the plants. Furthermore, pests settling on the plants were attracted to the apparatus, which used a plant-tapping method to drive them off the plants. Our study provided an experimental basis for developing an electrostatic device to attract and capture insects that enter greenhouses.

Anthonomus rubi on Strawberry Fruit: Its Biology, Ecology, Damage, and Control from an IPM Perspective.

The strawberry blossom weevil (SBW), Anthonomus rubi, is a well-documented pest of strawberry. Recently, in strawberry fields of Trento Province (north-east Italy), new noteworthy damage on fruit linked to SBW adults was observed, combined with a prolonged adult activity until the autumn. In this new scenario, we re-investigated SBW biology, ecology, monitoring tools, and potential control methods to develop Integrated Pest Management (IPM) strategies. Several trials were conducted on strawberry in the laboratory, field and semi-natural habitats. The feeding activity of adult SBW results in small deep holes on berries at different stages, causing yield losses of up to 60%. We observed a prolonged survival of newly emerged adults (>240 days) along with their ability to sever flower buds without laying eggs inside them in the same year (one generation per year). SBW adults were present in the strawberry field year-round, with movement between crop and no crop habitats, underlying a potential role of other host/feeding plants to support its populations. Yellow sticky traps combined with synthetic attractants proved promising for both adult monitoring and mass trapping. Regarding control, adhesive tapes and mass trapping using green bucket pheromone traps gave unsatisfactory results, while the high temperatures provided by the black fabric, the periodic removal of severed buds or adults and Chlorpyrifos-methyl application constrained population build-up. The findings are important for the development of an IPM strategy.

Synergistic Effects of the Red Light and Blue Traps on Control of Thrips palmi (Thysanoptera: Thripidae).

The melon thrips (Thrips palmi) is a serious insect pest of vegetables and ornamental plants. To control and monitor this thrips, blue traps are widely used. We previously reported that irradiation of cucumber plants with red light-emitting diodes (660 nm) causes T. palmi to avoid the plants. Here, we evaluated the responses of T. palmi adults to a cucumber plant in an experimental arena with either a transparent sticky trap or a blue sticky trap, without or with illumination by a red LED panel. When T. palmi were introduced into the arena, the number of thrips attracted to the plant was lowest in treatments using the red light and blue trap. On the other hand, when T. palmi were inoculated on plants first, most thrips stayed put on the plants. Placing both red LEDs and blue sticky traps in greenhouses before the thrips invade the greenhouse from the outside might effectively control T. palmi.

Evaluation of Sticky Traps for Monitoring Scolothrips sexmaculatus (Thysanoptera: Thripidae) and Stethorus punctum (Coleoptera: Coccinellidae) as Predators of Spider Mites in California Almonds.

Changes in almond production practices have caused sixspotted thrips, Scolothrips sexmaculatus Pergande, and the coccinellid beetle, Stethorus punctum LeConte, to replace phytoseiid mites as the dominant predators of spider mites in California almonds. We conducted a series of field studies to evaluate nine commercially available adhesive traps for S. sexmaculatus and S. punctum and found that the yellow strip trap was the most effective, least expensive, and easy to use. At peak population levels, individual cards routinely caught >1,000 S. sexmaculatus and >100 S. punctum trap-1 week-1. We documented that larger traps collected more S. sexmaculatus, and more S. sexmaculatus per square area, suggesting that the trap surface was attractive. We determined the number of traps needed to have 50, 70, and 90% confidence that the averages of trap captures were within 10, 30, and 50% of the population mean. Two yellow strip traps per orchard provided 90% confidence that trap captures were within 50% of the population mean if there were an average of 16.0 S. sexmaculatus trap-1 week-1 or 7.9 S. punctum trap-1 week-1. Populations required to attain the same levels of confidence using four traps per orchard were 3.9 S. sexmaculatus and 2.9 S. punctum trap-1 week-1. We conclude that use of the yellow strip trap to monitor for natural enemies, in combination with leaf samples for spider mites, has the potential to improve integrated pest management programs for spider mites, and assist future research to understand the biology and phenology of both predator species.

Season-Long Monitoring of the Brown Marmorated Stink Bug (Hemiptera: Pentatomidae) Throughout the United States Using Commercially Available Traps and Lures.

Reliable monitoring of the invasive Halyomorpha halys abundance, phenology and geographic distribution is critical for its management. Halyomorpha halys adult and nymphal captures on clear sticky traps and in black pyramid traps were compared in 18 states across the Great Lakes, Mid-Atlantic, Southeast, Pacific Northwest and Western regions of the United States. Traps were baited with commercial lures containing the H. halys pheromone and synergist, and deployed at field sites bordering agricultural or urban locations with H. halys host plants. Nymphal and adult captures in pyramid traps were greater than those on sticky traps, but captures were positively correlated between the two trap types within each region and during the early-, mid- and late season across all sites. Sites were further classified as having a low, moderate or high relative H. halys density and again showed positive correlations between captures for the two trap types for nymphs and adults. Among regions, the greatest adult captures were recorded in the Southeast and Mid-Atlantic on pyramid and sticky traps, respectively, with lowest captures recorded in the West. Nymphal captures, while lower than adult captures, were greatest in the Southeast and lowest in the West. Nymphal and adult captures were, generally, greatest during July-August and September-October, respectively. Trapping data were compared with available phenological models showing comparable population peaks at most locations. Results demonstrated that sticky traps offer a simpler alternative to pyramid traps, but both can be reliable tools to monitor H. halys in different geographical locations with varying population densities throughout the season.

Gravid oviposition sticky trap and dengue non-structural 1 antigen test for early surveillance of dengue in multi-storey dwellings: study protocol of a cluster randomized controlled trial.

BACKGROUND: Dengue is a global disease, transmitted by the Aedes vectors. In 2018, there were 80 615 dengue cases with 147 deaths in Malaysia. Currently, the nationwide surveillance programs are dependent on Aedes larval surveys and notifications of lab-confirmed human infections. The existing, reactive programs appear to lack sensitivity and proactivity. More efficient dengue vector surveillance/control methods are needed. METHODS: A parallel, cluster, randomized controlled, interventional trial is being conducted for 18 months in Damansara Damai, Selangor, Malaysia, to determine the efficacy of using gravid oviposition sticky (GOS) trap and dengue non-structural 1 (NS1) antigen test for early surveillance of dengue among Aedes mosquitoes to reduce dengue outbreaks. Eight residential apartments were randomly assigned into intervention and control arms. GOS traps are set at the apartments to collect Aedes weekly, following which dengue NS1 antigen is detected in these mosquitoes. When a dengue-positive mosquito is detected, the community will be advised to execute vector search-and-destroy and protective measures. The primary outcome concerns the the percentage change in the (i) number of dengue cases and (ii) durations of dengue outbreaks. Whereas other outcome measures include the change in density threshold of Aedes and changes in dengue-related knowledge, attitude and practice among cluster inhabitants. DISCUSSION: This is a proactive and early dengue surveillance in the mosquito vector that does not rely on notification of dengue cases. Surveillance using the GOS traps should be able to efficiently provide sufficient coverage for multistorey dwellings where population per unit area is likely to be higher. Furthermore, trapping dengue-infected mosquitoes using the GOS trap, helps to halt the dengue transmission carried by the mosquito. It is envisaged that the results of this randomized controlled trial will provide a new proactive, cheap and targeted surveillance tool for the prevention and control of dengue outbreaks. TRIAL REGISTRATION: This is a parallel-cluster, randomized controlled, interventional trial, registered at ClinicalTrials.gov (ID: NCT03799237), on 8th January 2019 (retrospectively registered).

Communities of oil palm flower-visiting insects: investigating the covariation of Elaeidobius kamerunicus and other dominant species.

Insects visit flowers not only to forage for nectar or pollen but also to search for hosts or prey, and to look for suitable habitats for breeding sites. In oil palm flowers, it has been documented that not all flower-visiting insects are pollinators, but some insects are recognized as predators, parasitoids or saprophages, which may affect the abundance and persistence of the weevil pollinating oil palm, Elaeidobius kamerunicus. We studied the community of oil palm flower-visiting insects and investigated the covariation between the abundance E. kamerunicus and that of other dominant species. Ecological research was conducted in oil palm plantations with different tree ages in Central Borneo. Our results found that tree age and flower type of oil palm did not influence the abundance and species richness of flower-visiting insects, but significantly affected their species composition. There was a significant positive relationship between the abundance of E. kamerunicus and the fly Scaptodrosophila sp, indicating that these species covariate in oil palm flowers. These findings suggest that understanding the covariation between E. kamerunicus and Scaptodrosophila sp may help develop the conservation strategies for E. kamerunicus to support the sustainable production of oil palm.

Sticky Trap Design Considerations for Entrapping Bed Bugs.

Little evidence has been presented on the usefulness of sticky traps for monitoring bed bugs, Cimex lectularius. We examined how the surface roughness around the adhesive of a sticky trap affects both bed bug behavior and adhesive entrapment. In the first assay, bed bugs were placed onto acetate paper discs with different roughness averages (Ra). Each disc was surrounded by sticky trap adhesive and number of captured bed bugs were recorded. The second assay was set up similarly to the first assay except that the outer portion of the acetate disc had a different Ra than the center. In the third assay, bed bugs were placed into circular acetate arenas where they were surrounded by different Ra treatments. The number of times the bed bugs contacted the Ra treatment but did not cross onto the treatment was recorded. Results of these assays showed that as the acetate surfaces got smoother (lower Ra), bed bugs were more likely to get trapped in sticky trap adhesives but also less likely to travel across the smoother surfaces they encountered. A sticky trap design with a smooth plastic film around the adhesive was tested in the field to see if it could capture bed bugs in apartments with known bed bug activity. This trap was not only able to capture bed bugs but was also able to detect unknown German cockroach, Blattela germanica, infestations. Sticky trap designs with smooth surfaces around an adhesive could be used to monitor not only bed bugs but also German cockroaches.

An Efficient Method for Monitoring Predatory Minute Pirate Bugs Orius spp. (Hemiptera: Anthocoridae) Populations Using Blue-Colored Sticky Traps.

Minute pirate bugs of genus Orius (Wolff) are known important generalist predators of microinvertebrate pests and are therefore useful in many agricultural contexts. Effective sampling methods are thus of great importance to monitor Orius spp. populations. Sticky traps are one such sampling method; however, trap color must be carefully selected for the target insect species. In this study, we examined the most suitable sticky trap color (i.e., white, blue, or yellow) to capture Orius spp. individuals in eggplant Solanum melongena (Linnaeus) (Solanales: Solanaceae), Italian ryegrass Lolium multiflorum (Lamarck) (Poales: Poaceae), soybean Glycine max (Linnaeus) (Fabales: Fabaceae), and white clover Trifolium repens (Linnaeus) (Fabales: Fabaceae) fields. More Orius spp. adults were caught on blue and white traps than on yellow traps. The white traps also caught other insects, which hampered the counting of Orius spp. individuals and, therefore, reduced trapping efficiency. In addition, seasonal prevalence investigations showed that blue sticky traps had similar patterns to those of field observations. Thus, as the blue sticky trap can avoid capturing nontarget insects, we concluded that blue was the most suitable trap color for monitoring Orius spp. In addition, because blue sticky traps are more efficient and less-labor intensive, they can be useful as an alternative to field observations.

Population Development of the Invasive Species Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae) on four Eucalyptus Species of the Subgenus Symphyomyrtus.

Thaumastocoris peregrinus Carpintero & Dellapé (Hemiptera: Thaumastocoridae) is a small sap-sucking insect that feeds on Eucalyptus L'Hér. leaves. Although it is native to Australia, it currently has a global distribution and it is considered as one of the big five pests of eucalypts around the world. We described the development of T. peregrinus population on four Eucalyptus species under the environmental conditions in Argentina. We also analyzed the use of yellow sticky traps as a monitoring method for this pest. The four Eucalyptus species were suitable for T. peregrinus. A cyclic pattern was observed in the development of the bronze bug population with an annual seasonal peak followed by a decrease in the abundance, reaching a minimum value during the unfavorable seasons. During the fall and winter seasons, epizootic events were registered in all the Eucalyptus species, caused by an entomopathogenic fungus. None of the meteorological variables had a clear influence neither on the bronze bug population nor with the occurrence of fungal infection. We found a significant relationship between the number of nymphs and adults of T. peregrinus in branches and the number of individuals caught in traps, suggesting that traps give actual information about the bronze bug abundance in the tree canopy.

Field Evaluation of Potential Pheromone Lures for Lygus lineolaris (Hemiptera: Miridae) in the Mid-South.

Plant bugs (Hemiptera: Miridae) are phytophagous pests of cultivated plants around the world. In the mid-South region of the United States, Lygus lineolaris (Palisot de Beauvois) is a primary pest of cotton, and causes economic damage. Previously published research about the volatiles produced by members of the genus Lygus, and other closely related groups, indicated that they produce blends of hexyl butyrate, (E)-2-hexenyl butyrate, and (E)-4-oxo-2-hexenal. Varying ratios of the three compounds were loaded into pipette tips, and screened in combination with non-UV white sticky cards for attractiveness to field populations of L. lineolaris in Mississippi. Field screening indicated that a lure expressing a ratio of 4:10:7 was the most effective at collecting L. lineolaris, and collected similar numbers of individuals to those reported in other studies using traps baited with live virgin insects over a similar period of time. Availability of a synthetic pheromone usable in the climate of the mid-South will enable broader scale landscape level monitoring for populations of L. lineolaris before movement into cotton fields and resulting economic damage.

(Z)-9-Tricosene based Musca domestica lure study on a garbage dump yard using plywood sticky trap baited with fish meal.

A study was undertaken to find out the efficacy of (Z)-9-Tricosene in attracting flies in a garbage dump yard using a plywood sticky glue trap with fish meal as a food bait. (Z)-9-Tricosene was dissolved in acetone or hexane before application on a filter paper strip fixed at the centre of the trap. The traps were left in areas of the garbage dump yard of high fly activity for 6 h and then the trapped flies were counted species wise. Significantly more number of Musca domestica flies were caught in (Z)-9-Tricosene treated fish meal baited traps compared to those traps without (Z)-9-Tricosene. No significant difference was noted in trap catches in (Z)-9-Tricosene treated traps between the solvents acetone and hexane. In addition Sarcophaga sp. and Chrysomyia sp. flies were also caught in the traps.

Enhancement of Aedes albopictus collections by ovitrap and sticky adult trap.

BACKGROUND: In the last decades, Aedes albopictus has become an increasing public health threat in tropical as well as in more recently invaded temperate areas due to its capacity to transmit several human arboviruses, among which Dengue, Chikungunya and Zika. Enhancing the efficiency of currently used collection approaches, such as ovitraps and sticky traps, is desirable for optimal monitoring of the species abundance, for assessment of the risk of arbovirus transmission and for the optimisation of control activities. FINDINGS: Two sets of 4 × 4 Latin-square experiments were carried out in Tirana (Albania) to test whether modifications in ovitrap shape and size and in oviposition substrate would increase collections of Ae. albopictus eggs and whether hay-infusion would increase adult catches by sticky trap. Generalized Linear Mixed Models with negative binomial error distribution were carried out to analyse the data. Cylindrical ovitraps lined with germination paper yielded significantly higher egg catches than those exploiting either the (commonly used) wooden paddles or floating polystyrene blocks as oviposition substrates. No difference was observed between cylindrical and conical shaped ovitraps. Ovitraps and sticky traps baited with hay infusion yielded significantly higher egg and adult catches than un-baited ones. A significant relationship between ovitrap and sticky trap catches was observed both in the absence and in the presence of attractants, with ovitrap catches increasing more than sticky trap catches at increasing adult female densities. CONCLUSIONS: This study provides grounds for optimisation of ovitraps and sticky traps as monitoring tools for Ae. albopictus by (i) supporting use of germination paper as most appropriate oviposition substrate; (ii) suggesting the possible use of stackable conical ovitraps for large scale monitoring; (iii) confirming the use of hay-infusion to increase egg catches in ovitraps, and showing that hay-infusion also significant increases adult catches by sticky traps.