High Infestation Levels Research Articles

An economic evaluation of cattle tick acaricide-resistances and the financial losses in subtropical dairy farms of Ecuador: A farm system approach.

Estimates of economic losses in cattle due to tick infestations in subtropical areas are limited, such as in Ecuador. Ticks affect animal production and health, but those direct effects are difficult to estimate since financial exercises carried out in farms consider both costs of the inputs and revenues. This study aims to quantify the costs of inputs involved in milk production and to know the role of acaricide treatment in the production costs on dairy farms in subtropical zones using a farming system approach. Regression and classification trees were used to study the relationship between tick control, acaricide resistance and the presence of high level of tick infestation in the farm system. Even though there was no significant direct association between high levels of tick infestation and the presence of acaricide resistance in ticks, a more complex structure for resistances operates in the manifestation of high tick infestation involving levels of farm technology and no acaricide resistance. Farms with higher levels of technology allocate a lower percentage of sanitary expenses to control ticks (13.41%) in comparison to semi-technified (23.97%) and non-technified farms (32.49%). Likewise, more technified and bigger herds have a lower annual expenditure on acaricide treatment (1.30% of the production budget equivalent to 8.46 USD per animal) compared to non-technified farms where it can represent more than 2.74% of the production budget and where the absence of cypermethrin resistance increases the treatment cost to 19.50 USS per animal annually. These results can motivate the development of information campaigns and control programmes targeted to the reality of small and medium farms that are the most affected in terms of the money they invest in controlling ticks.

Weed infestation of switchgrass (Panicum virgatum L.) crops

Purpose. Determination of the species composition of weeds in switchgrass crops and their influence on the formation of biomass productivity. Methods. Field, laboratory, quantitative-weighing, calculation-comparative, mathematical-statistical. Results. The results of studies on weed infestation of switchgrass crops and methods of their control are highlighted. A mixed type of weediness was observed in the crops, consisting of 19 species from 8 families, with a predominance of annual dicotyledonous species (75.0-87.2%). While in the third (91.7-95.1%) and fifth (61.0-91.7%) years of vegetation, perennial dicot species such as Erigeron canadensis, Lactuc aserriola L., Artemisia annua L., thistles ones, annual dicotyledons were not present. When analyzing the quantitative composition of weeds in the first year of vegetation on the weedy control, high level of weed infestation was observed, which amounted to 176 pcs./m2, in the second and third years 103-105 pcs./m2, in the fourth – 74 pcs./m2 and in the fifth – 39 pcs./m2 . In the variants where weed control was used in the third and subsequent years a decrease in the number of weeds by 83.5-88.4% was noted compared to the control. The use of herbicides on crops ensured efficiency in the first year of vegetation at the level of 72.3-76.9%, while in the fifth year it was 95.3-96.2%. Weed control allowed increasing the biomass yield to 10.7-10.8 t/ha, while the weeded control yielded 8.8 t/ha. Conclusions. The use of herbicides (Dialen super 464 SL, Caliber 50) led to a decrease in the number of weed plants from 28.6% in the first year of vegetation to 88.3% in the fifth year, providing a 72.3-97.6% efficiency depending on the year of vegetation of the crop. Weed controll in the fifth year of crop vegetation made it possible to obtain 11.0 t/ha of dry biomass, 11.9 t/ha of solid fuel, 220 GJ/ha energy from fuel.

Effective Striga control and yield intensification on maize farms in western Kenya with N fertilizer and herbicide-resistant variety.

Maize production in western Kenya is limited by the spread of parasitic weed Striga hermonthica and depletion of soil nutrient stocks. Nitrogen (N) fertilizer and imidazolinone resistant (IR) maize are key elements in the agronomic toolbox to control infestations and enhance yields. The circumstances under which their use, individually or combined, is most effective on farmer fields have not been well documented. Inappropriate management decisions and low returns on investments arise from this knowledge gap, causing hunger and poverty in smallholder communities to persist. Experiments were carried out on 60 fields in three different agroecosystems of western Kenya using full-factorial treatments with non-herbicide treated maize (DH) and herbicide treated maize (IR), and N fertilizer omission and application. Trials were stratified on a field with low and high soil fertility within individual farms and repeated over two seasons. Cultivating IR maize instead of DH maize decreased the emergence of Striga with 13 shoots m-2 on average while applying N fertilizer on DH maize led to a reduction of 5 shoots m-2 on average. Decreases of Striga by use of IR maize and N fertilizer were between 6 and 23 shoots m-2 larger at the site with high levels of infestation than at the sites with medium or low emergence. Input of N fertilizer increased grain harvests by 0.59 ton ha-1 on average while use of IR maize enhanced the productivity with 0.33 ton ha-1 on average. Use of N fertilizer had similar yield effects in all three sites, whereas use of IR maize at the site with high Striga emergence increased maize production by 0.26-0.39ton ha-1 more than at the sites with medium or low emergence. The greater Striga responses to IR maize and the greater yield responses to N fertilizer demonstrate their use could be optimized according to field conditions and management goals. Combining IR maize and N fertilizer has larger added yield benefits where their individual effects on grain productivity are smaller. Findings from this study indicate that farmers in western Kenya require guidance on how to align the use of herbicide resistant maize and inorganic N inputs with the level of Striga infestation and maize yield on their fields for effectively controlling the pernicious weed and enhancing food production.

Integrative analysis of green ash phloem transcripts and proteins during an emerald ash borer infestation

BackgroundEmerald ash borer (Agrilus planipennis; EAB) is an Asian insect species that has been invasive to North America for 20 years. During this time, the emerald ash borer has killed tens of millions of American ash (Fraxinus spp) trees. Understanding the inherent defenses of susceptible American ash trees will provide information to breed new resistant varieties of ash trees.ResultsWe have performed RNA-seq on naturally infested green ash (F. pennsylvanica) trees at low, medium and high levels of increasing EAB infestation and proteomics on low and high levels of EAB infestation. Most significant transcript changes we detected occurred between the comparison of medium and high levels of EAB infestation, indicating that the tree is not responding to EAB until it is highly infested. Our integrative analysis of the RNA-Seq and proteomics data identified 14 proteins and 4 transcripts that contribute most to the difference between highly infested and low infested trees.ConclusionsThe putative functions of these transcripts and proteins suggests roles of phenylpropanoid biosynthesis and oxidation, chitinase activity, pectinesterase activity, strigolactone signaling, and protein turnover.

Parental food provisioning and nestling growth under Philornis downsi parasitism in the Galapagos Green Warbler-Finch, classified as ‘vulnerable’ by the IUCN

In the Galapagos Islands, many endemic landbird populations are declining due to habitat degradation, food availability, introduced species and other factors. Given nestlings typically lack efficient defense mechanisms against parasites, hematophagous ectoparasites such as the larvae of the introduced Avian Vampire Fly, Philornis downsi, can impose high brood mortality and cause threatening population declines in Darwin finches and other landbirds. Here, we assess whether the food compensation hypothesis (i.e., the parents’ potential to compensate for deleterious parasite effects via increased food provisioning) applies to the Green Warbler-Finch. We differentiated nests with low or high infestation levels by P. downsi and quantified food provisioning rates of male and female parents, time females spent brooding nestlings, and nestling growth. Male provisioning rates, total provisioning rates and female brooding time did not significantly vary in relation to infestation levels, nor by the number of nestlings. Opposed to the predictions of the food compensation hypothesis, females showed significantly reduced provisioning rates at high infestation levels. Nestling body mass was significantly lower and there was a reduction of skeletal growth, although not significantly, in highly infested nests. The females’ response to high infestation may be due to parasites directly attacking and weakening brooding females, or else that females actively reduce current reproductive effort in favor of future reproduction. This life-history trade-off may be typical for Darwin finches and many tropical birds with long lifespans and therefore high residual reproductive value. Conservation strategies may not build on the potential for parental food compensation by this species.

All together now: Geographically coordinated miticide treatment benefits honey bee health.

Deformed wing virus (DWV) is a pathogenic virus of honey bees transmitted by the ectoparasitic mite Varroa destructor. Annual overwintering colony losses, accounting for ~25% of all colonies, are associated with high levels of Varroa-DWV infestation. Effective miticide treatments are available to control Varroa. However, the absence of coordinated treatment means environmental transmission of mites continues unchecked. We aimed to determine whether rational, coordinated treatment is beneficial, and characterized the DWV population as an indicator of colony health.This study uses coordinated treatment of Varroa in a geographically isolated environment (Isle of Arran, Scotland) over 3 years. The study area contained 50-84 colonies managed by ~20 amateur beekeepers. Sampling and virus analysis to assess strain diversity and viral loads were conducted before and after treatments, and changes in population diversity were quantified by sequence analysis.Over the 3 years analysis of the virus population revealed that the dominant DWV variant shifted from Type A to Type B in all apiaries, regardless of mite levels or proximity to other colonies. During this period the number of managed colonies increased by 47% (57-84 colonies), but despite this, we estimate total mite numbers decreased by 58%. Synthesis and applications. In this study, the beekeepers in Arran significantly improved the number of colonies they managed, without importing any bees onto the island, indicating that an improved focus on management techniques, through the combination of a coordinated miticide programme and an improved understanding of bee diseases, could yield positive results for bee health and sustainability.

Occurrence and spread of invasive thrips <i>Thrips parvispinus</i> (Karny) in north India

The invasive thrips Thrips parvispinus (Karny) (Thysanoptera: Thripidae) is an important insect pest causing severe damage in chilli-growing areas of south India in the last two years. In the present study, its spread in north and central India in chilli and capsicum is discussed along with diagnosis, occurrence, damage symptoms. A high level of infestation (ranging from 8-12 thrips/ flower) was observed on chilli crop in Madhya Pradesh (Khargone, Khandwa, Satna, Narasinghpur, Dhar) and on capsicum hybrids in Haryana (Ambala, Panchkula and Panipat) grown under greenhouse. However, its infestation was less (1-3 thrips/ flower) in chilli crop at Chhattisgarh (Bastar, Sarangarh-Bilaigarh, Balod bazar, Durg).

Using Species Distribution Models (SDMs) to Estimate the Suitability of European Mediterranean Non-Native Area for the Establishment of Toumeyella Parvicornis (Hemiptera: Coccidae).

The pine tortoise scale, Toumeyella parvicornis, is an insect native to the Nearctic region that is able to infest several Pinus species. It can cause weakening, defoliation and, at high infestation levels, tree death. After its first report in Italy in 2015, the pest spread rapidly over the surrounding areas and was reported in France in 2021. Due to the threat that this pest poses to pine trees, the suitability of European Mediterranean basin areas for T. parvicornis at different spatial scales was estimated by constructing species distribution models (SDMs) using bioclimatic variables. Our results showed that several coastal areas of the Mediterranean basin area could be suitable for T. parvicornis. Based on performance assessment, all the SDMs tested provided a good representation of the suitability of European Mediterranean non-native area for T. parvicornis at different spatial scales. In particular, most of the areas with a medium or high level of suitability corresponded to the geographical range of distribution of different Pinus spp. in Europe. Predicting the suitability of European Mediterranean areas for T. parvicornis provides a fundamental tool for early detection and management of the spread of this pest in Europe.

Morphological traits and sustainability of plus shea trees (Vitellaria paradoxa C.F.Gaertn.) in Côte d'Ivoire

Description of the subject. Shea tree (Vitellaria paradoxa C.F.Gaertn.) is an essential component of natural/semi-natural savannas and agroforestry systems of Africa. It contributes to local household incomes and represents an important cash crop for export. It is important to improve our knowledge about the viability and genetic diversity of “plus shea tree” (PST: shea trees whose genetic superiority has not yet been proven by an appropriate progeny test) genotypes to conserve the genetic diversity of the species and the potential for producing improved species. Objectives. We characterized the diversity of an in situ PST collection in Côte d’Ivoire and evaluated its long-term sustainability. Method. Twelve qualitative morphological traits were studied on 220 PSTs randomly sampled among 405 PSTs also randomly selected from in situ collections in the Bagoué and Tchologo districts of northern Côte d’Ivoire to assess in situ conservation sustainability. Results. Most qualitative morphological traits were highly diverse based on the Shannon diversity index (0.55-0.98 range) with significant differences between districts. Hierarchical ascending classification gathered the PSTs into three groups. The lack of sustainability of the in situ collection for long-term conservation of the species was confirmed because it is endangered by a high mortality rate (8.15% after three years) and high levels of infestation by Loranthaceae (83.68%). Conclusions. We recommend the establishment of an ex situ collection of shea trees managed by a research organization to preserve this important genetic heritage. To maximize the genetic diversity of the future ex situ collection, we suggest establishing a core collection based on molecular diversity characterized from molecular markers, such as single nucleotide polymorphism (SNP).

Plasticity in oviposition and foraging behavior in the invasive pest Drosophila suzukii across natural and agricultural landscapes.

The effects and extent of the impacts of agricultural insect pests in and around cropping systems is a rich field of study. However, little research exists on the presence and consequence of pest insects in undisturbed landscapes distant from crop hosts. Research in such areas may yield novel or key insights on pest behavior or ecology that is not evident from agroecosystem-based studies. Using the invasive fruit pest Drosophila suzukii (Matsumura) as a case study, we investigated the presence and resource use patterns of this agricultural pest in wild blackberries growing within the southern Appalachian Mountain range of North Carolina over 2 years. We found D.suzukii throughout the sampled range with higher levels of infestation (D.suzukii eggs/g fruit) in all ripeness stages in natural areas when compared with cultivated blackberry samples, but especially in under-ripe fruit. We also explored a direct comparison of oviposition preference between wild and cultivated fruit and found higher oviposition in wild berries when equal weights of fruit were offered, but oviposition was higher in cultivated berries when fruit number was equal. Forest populations laid more eggs in unripe wild-grown blackberries throughout the year than populations infesting cultivated berries. This suggests D.suzukii may change its oviposition and foraging behavior in relation to fruit type. Additionally, as D.suzukii exploits a common forest fruit prior to ripeness, further research is needed to explore how this affects wild food web dynamics and spillover to regional agroecosystems.

Pest management and pesticide used in some Hospitals of Benghazi

Public health pest management involves the control of insects or other vectors that transmit diseases to humans. These pests include mosquitoes, cockroaches, bedbugs and domestic rodents. Chemical pesticides assisted in containing the spread of infection and helped reduce infestations with pests. On the other hand, it may have a high-risk acute toxicity and/or chronic effects, which are dangerous, especially to children. Furthermore, they can cause cancer, neurologic damage, delayed development, reproductive dysfunction, and death in many parts of the world, generally through occupational exposure and accidental poisoning of patients. The current study was based on public hospitals in Benghazi city of Libya using questionnaires to collect data in 2013 and then completed in 2015-2016. The results showed a high level of infestation in the hospitals that were studied. The major insect pest species was the German cockroach (Blattella germanica). Insect control agents containing permethrin, cypermethrin, deltamethrin were used. In addition to different formulations such as baits, traps, gel baits that contain hydramethylnon, imidacloprid, chlorpyriphos. The study acknowledges the benefits those pesticides carried out to hospitals, but also understanding their potential harm and side effects. The most important finding is that pesticides are used extensively in Benghazi’s hospitals. More than 15 different pesticides are presently applied in hospitals, such as fog, spray, and powder pesticides. They are applied in mostly all areas, including areas that contain patients. On the bright side, the study finds that hospitals in Benghazi have started to use less toxic pesticides and try to use other pesticides in safe ways.

Early Onset Yellow Rust Detection Guided by Remote Sensing Indices

Early warning systems help combat crop diseases and enable sustainable plant protection by optimizing the use of resources. The application of remote sensing to detect plant diseases like wheat stripe rust, commonly known as yellow rust, is based on the presumption that the presence of a disease has a direct link with the photosynthesis capability and physical structure of a plant at both canopy and tissue level. This causes changes to the solar radiation absorption capability and thus alters the reflectance spectrum. In comparison to existing methods and technologies, remote sensing offers access to near real-time information at both the field and the regional scale to build robust disease models. This study shows the capability of multispectral images along with weather, in situ and phenology data to detect the onset of yellow rust disease. Crop details and disease observation data from field trials across the globe spanning four years (2015–2018) are combined with weather data to model disease severity over time as a value between 0 and 1 with 0 being no disease and 1 being the highest infestation level. Various tree-based ensemble algorithms like CatBoost, Random Forest and XGBoost were experimented with. The XGBoost model performs best with a mean absolute error of 0.1568 and a root mean square error of 0.2081 between the measured disease severity and the predicted disease severity. Being a fast-spreading disease and having caused epidemics in the past, it is important to detect yellow rust disease early so farmers can be warned in advance and favorable management practices can be implemented. Vegetation indices like NDVI, NDRE and NDWI from remote-sensing images were used as auxiliary features along with disease severity predictions over time derived by combining weather, in situ and phenology data. A rule-based approach is presented that uses a combination of both model output and changes in vegetation indices to predict an early disease progression window. Analysis on test trials shows that in 80% of the cases, the predicted progression window was ahead of the first disease observation on the field, offering an opportunity to take timely action that could save yield.

Бидайдың сары тат (Puccinia striiformis f.sp. tritici) ауруына Алматы облысы бойынша 2019–2021 жылдары жүргізілген мониторингі

Yellow rust (P. striiformis f.sp.tritici) is an important disease of wheat (Triticum aestivum), especially in cool and moist weather conditions. In Central Asian countries, including Kazakhstan, yellow rust remains a serious disease in wheat crop area. In our research 2019–2020 in the Almaty region in Zhambyl, Karasai, Talgar regions, cultivars were selected, that have high resistance to the P. striiformis pathogen, which showed the immune type of reaction “IT — 0: Vassa”, “Naz”, “Bezostaya-1”, “Sapaly”, and “Triticale”. At the same time, based on the data of phytopothological monitoring, in the Zhambyl region, the greatest spread of the disease was observed in the cultivar “Bogarnaya 56”, the prevalence was 26%, and the level of infestation was 9.90%. In the Talgar region, in the winter wheat cultivar “Kazakhstan–10”, the prevalence of yellow rust disease was 6%, and the level of infection was 0.52%. In the Karasai region, the cultivar “Karasai” was found to have a high level of yellow rust infestation, the prevalence of the disease was 22%, and the infestation was 1.04%. In addition, as a result of the monitoring carried out in 2021, the obtained data demonstrated that all the studied wheat cultivars were resistant to the P. striiformis pathogen due to dry weather and lack of precipitation, low humidity resistance to the disease was high. Research shows the need for continued work to find new sources of yellow rust resistance. The results of the experiment show that most of the wheat varieties in the Almaty region are not resistant to rust diseases.

Growth, Laying, and Survival Rates of the Galba truncatula Snails Infected with Fasciola hepatica

Fasciolosis is one of the most important parasitic diseases in ruminants in Algeria, of which the intermediate host is Galba truncatula (G. truncatula) snail. The current study aimed to investigate the prevalence of Fasciola sp. in naturally infected G. truncatula snails using multiplex PCR. Secondly, it was targeted toward examining the rate of growth, survival, and laying of the snails in experimental conditions during 6 weeks of rearing in three tanks. This study was conducted in two different regions of Algeria, namely El Tarf and Constantine. The investigated tanks 1, 2, and 3 consisted of 12 (size 3-4 mm), 30 (size 5-6 mm), and 30 (size 7-8 mm) snails, respectively. Fasciola sp. DNA was detected in 33.33% of G. truncatula snails (25% in Constantine and 42.85% in El Tarf). The total survival rates in the first, second, and third tanks were 50%, 43.3%, and 40%, respectively. The obtained results indicated that the growth rate of the snail depended on its initial size (the smaller the initial size, the higher the weekly growth rate). The total growth rates were 3, 1.7, and 1.1 mm in tanks 1, 2, and 3, respectively. The use of multiplex PCR indicated a relatively high level of infestation of the snails by Fasciola sp. Snails larger than 7 mm had the highest lay rate. Further studies are needed to investigate other snails that may be infested with Fasciola sp.

Evaluation of the Egg Predator Blattisocius tarsalis (Mesostigmata: Blattisociidae) for the Biological Control of the Potato Tuber Moth Tecia solanivora under Storage Conditions

Tecia solanivora is the most prevalent pest causing damage to potato crops in fields in the Canary Islands, but even more so in the postharvest storage period. However, currently, there are no authorised chemical insecticides for potato storage facilities. Analysis of the viability of the predator mite Blattisocius tarsalis as a biological control agent for this moth was carried out. A study of the temperature effect showed B. tarsalis maintains predatory capacity in the range of 10–27 °C. Though predatory activity increases with temperature, no differences in mortality rates were observed between 10 and 20 °C (33.52 ± 2.44 and 40.14 ± 3.54% efficacy rate, respectively), nor between 25 and 27 °C (59.26 ± 4.59 and 75.19 ± 4.64% efficacy rate, respectively). Under microcosm conditions, at low pest infestation (10 eggs), B. tarsalis achieved the highest mortality of eggs at a density of 5 mites, with an efficacy rate of 91.67 ± 8.33%. At high infestation levels (50 eggs), maximum mortality was achieved with a density of 10 mites and efficacy of 98.52 ± 1.48%. The choice-assay showed no preference of B. tarsalis between T. solanivora and Phthorimaea operculella, suggesting this mite could be useful in mixed infestations of potato moths. The results show B. tarsalis is a very good candidate as a control agent in storage conditions and even in mixed infestations of T. solanivora and P. operculella.

Soil Seed Bank Dynamics of Pastures Invaded by Navua Sedge (Cyperus aromaticus) in Tropical North Queensland

Navua sedge (Cyperus aromaticus) is threatening crops, pasture species and natural ecosystems in Pacific Island countries and northern Queensland, Australia. To aid future management efforts of this exotic invasive weed, research was conducted to understand the soil seed bank dynamics of pastures invaded by Navua sedge. Six grazing properties were chosen across two landscapes, coastal and inland/upland, with areas that had Navua sedge infestations in Queensland, Australia. At each site, soil was collected from two soil depths, 0-5 and 5-10 cm, and from plots with high and low infestation levels of Navua sedge. It was observed that the soil seed bank dynamics varied significantly between these study sites. Navua sedge was the dominant species in the soil seed bank at all the sites contributing between 62% to 95% of the total seed bank, while pasture seeds occupied only 3% to 24%. Broadleaf seeds were even lower in abundance, showing between 2% to 13% of the total seed count. The abundance of Navua sedge seed present in the soil was significantly correlated with the aboveground biomass of Navua sedge (r=0.53, p=0.006), but no correlation was found with the infestation age of Navua sedge. Based on this work, it is clear that the seed bank of Navua sedge is very large and concentrated within the top 0-5 cm of the soil, with, 83% of total Navua sedge seeds being in this layer. It was also noted that, although, high infestation plots had significantly higher number of seeds than low infestation plots, more than 18,000 Navua sedge seeds/m2 were still found in the 0-5 cm soil layer of plots regarded as low infestation. We suggest that insights achieved from our soil seed bank study may be used to devise management strategies to minimise the impact of Navua sedge weed in critical grazing and agricultural areas.

Molecular investigation of Babesia caballi in horses from the state of Rio de Janeiro, Brazil: Epidemiological aspects associated with the infection.

The epidemiological aspects of Babesia caballi infection were evaluated in 516 horse samples from Rio de Janeiro, Brazil. The presence and infestation level of ticks on horses, breed conditions, and animal management were evaluated on each farm through an epidemiological questionnaire. The gene that codes for rhoptry-associated protein-1 (RAP-1) of B. caballi was amplified by nested PCR (nPCR). Among the horses sampled, 17.2% (n=89/516) presented B. caballi DNA. The characterized samples showed 99-100% similarity with other isolates of B. caballi based on the RAP-1 gene, available in GenBank. In the final logistic regression model, the variables associated with B. caballi infection in horses were as follows: age below two years (OR=3.33; IC=1.7-6.5), farms located in low altitudes (OR=3.52; IC=1.7-7.3) and Dermacentor nitens infestation (OR=1.91; IC=1.1-3.4). Furthermore, a high level of D. nitens infestation in horses was also a factor associated with positivity for B. caballi (OR=2.11; IC=1.25-3.54). In summary, young horses bred in low altitude regions characterized with high temperatures, and infested by D. nitens, mainly with a higher level of infestation, are more likely to be infected by B. caballi. This epidemiological study provides statical evidence that the D. nitens tick play a role as the biological vector of B. caballi in the studied region.

The Associated Decision and Management Factors on Cattle Tick Level of Infestation in Two Tropical Areas of Ecuador.

Decision-making on tick control practices is linked to the level of knowledge about livestock farming and to the social context in which individuals practice them. Tick infestation is one of the main problems in tropical livestock production. The objective of this study was to characterize tick-control related practices in two tropical livestock areas and their potential association with the level of tick infestation. A total of 139 farms were included in this survey. To determine this association, a multivariate logistic regression model was used. A stepwise model selection procedure was used and model validation was tested. Cattle husbandry as a main activity, the use of external paddocks, the use of amitraz, and the lack of mechanization on the farm were related with high tick infestation. On the other hand, owner involvement in the preparation of acaricide solution was identified as a protective factor against high tick infestation. At animal level, age (old), body condition status (thin), and lactation were also associated with high tick infestations, while Bos primigenius indicus cattle and their crosses reduced the probability of high tick infestations. The factors studied, such as herd size, education level of the owners, and veterinary guidance, varied from farm to farm. Nonetheless, these differences did not generate changes in the level of tick infestation. According to the area under the receiver operating characteristic curve (AUC-ROC), the model at farm level predicts a high level of infestation, with an accuracy of 72.00% and high sensitivity. In addition, at animal level, crossbreeding with indicus cattle and breeding selection for host resistance will be useful against high tick infestation. Likewise, the implementation of programs of capacitation and research on tick control for farmers, cowboys, and vets in these areas is necessary.

Impact of Bemisia tabaci MEAM1 (Hemiptera: Aleyrodidae) on Soybean Yield and Quality Under Field Conditions.

Bemisia tabaci MEAM1 (Hemiptera: Aleyrodidae) is a key insect pest in soybean fields in Brazil but data are lacking on the relationship between pest abundance and crop yield and quality. Controlled infestation studies were conducted on caged soybean plants in the field over a two year period at two sites in Brazil. Differences in temperature in the two years affected population growth of B. tabaci, reaching 413 nymphs per leaflet in the first year, and 179 the second year even when the average temperature was 3ºC higher. Higher temperatures promoted a shorter lifecycle and nearly one more generation. Yield was affected with losses up to 500 kg/ha in 2017/2018 and 1,147 kg/ha in 2018/2019. A decrease in the weight of a thousand grains of 18 and 33 g was observed in the first and second year, respectively. No significant differences were observed in grain germination, but estimated losses in protein content were up to 440 kg/ha at the highest infestation level. Pest density and yield data were used to estimate economic injury levels (EILs). EILs ranged from 2.5 to 25.67 nymphs per leaflet and 0.17-1.79 adults per leaflet over a range of control costs, soybean production values, and control efficacies. These results should provide data useful toward development of pest management decision making tools.

Morphological, Molecular and MALDI-TOF MS Identification of Bedbugs and Associated Wolbachia Species in Rural Senegal.

Bed bugs are known to carry several microorganisms. The purpose of this study was to assess the prevalence of bed bug infestation in two rural areas of Senegal and determine the species present in the population. A screening was conducted to detect some arthropod associated pathogenic bacteria in bed bugs and to evaluate the prevalence of endosymbiont carriage. One survey took place in 17 villages in Niakhar and two surveys in Dielmo and Ndiop and surroundings area in the same 20 villages. Bed bugs collected were identified morphologically and by MALDI-TOF MS tools. Microorganisms screening was performed by qPCR and confirmed by sequencing. During the survey in the Niakhar region, only one household 1/255 (0.4%) in the village of Ngayokhem was found infested by bed bugs. In a monitoring survey of the surroundings of Dielmo and Ndiop area, high prevalence was found during the two rounds of surveys in 65/314 (21%) in 16/20 villages (January-March) and 93/351 (26%) in 19/20 villages (December). All bed bugs were morphologically identified as the species Cimex hemipterus, of which 285/1,637 (17%) were randomly selected for MALDI-TOF MS analysis and bacteria screening. Among the Bacteria tested only Wolbachia (Alphaproteobacteria, Rickettsiales, Rickettsiaceae) DNA was found in 248/276 (90%) of the bedbugs. We briefly describe a high level of non-generalized bed bug infestation in rural Senegal and the diversity of Wolbachia strains carried by C. hemipterus. This study opens perspectives for raising household awareness of bed bug infestations and possibilities for appropriate control.