Showing papers on "Infestation published in 2015"
TL;DR: Unless effective means to reduce contact between people and palm-living triatomines are devised, palms will contribute to maintaining long-term and widespread, albeit possibly low-intensity, transmission of human Chagas disease.
76 citations
TL;DR: The prevalence of head lice infestation among Iranian primary school children is relatively high with more prevalence among girls, and it is found that economic, social, cultural, behavioral, and hygienic factors are associated with this infestation.
Abstract: Objectives
Head lice infestation is one of the most important health problems, generally involving children aged 5–13 years. This study aims to estimate the prevalence of head lice infestation and its associated factors among primary school children using systematic review and meta-analysis methods.
64 citations
TL;DR: The addition of sucrose to insecticides targeting spotted wing drosophila, Drosophila suzukii (Matsumura), enhanced lethality in laboratory, semifield, and field tests.
Abstract: The addition of sucrose to insecticides targeting spotted wing drosophila, Drosophila suzukii (Matsumura), enhanced lethality in laboratory, semifield, and field tests. In the laboratory, 0.1% sucrose added to a spray solution enhanced spotted wing drosophila feeding. Flies died 120 min earlier when exposed to spinosad residues at label rates enhanced with sucrose. Added sucrose reduced the LC50 for dried acetamiprid residues from 82 to 41 ppm in the spray solution. Laboratory bioassays of spotted wing drosophila mortality followed exposure to grape and blueberry foliage and/or fruit sprayed and aged in the field. On grape foliage, the addition of 2.4 g/liter of sugar with insecticide sprays resulted in an 11 and 6% increase of spotted wing drosophila mortality at 1 and 2 d exposures to residues, respectively, averaged over seven insecticides with three concentrations. In a separate experiment, spinetoram and cyantraniliprole reduced by 95-100% the larval infestation of blueberries, relative to the untreated control, 7 d after application at labeled rates when applied with 1.2 g/liter sucrose in a spray mixture, irrespective of rainfall; without sucrose infestation was reduced by 46-91%. Adding sugar to the organically acceptable spinosyn, Entrust, reduced larval infestation of strawberries by >50% relative to without sugar for five of the six sample dates during a season-long field trial. In a small-plot field test with blueberries, weekly applications in alternating sprays of sucrose plus reduced-risk insecticides, spinetoram or acetamiprid, reduced larval infestation relative to the untreated control by 76%; alternating bifenthrin and phosmet (without sucrose) reduced infestation by 65%.
59 citations
TL;DR: Results show a severe spruce beetle infestation, which results in the depletion of susceptible hosts, can create a landscape template reducing the potential for future infestations.
Abstract: Understanding disturbance interactions and their ecological consequences remains a major challenge for research on the response of forests to a changing climate. When, where, and how one disturbance may alter the severity, extent, or occurrence probability of a subsequent disturbance is encapsulated by the concept of linked disturbances. Here, we evaluated 1) how climate and forest habitat variables, including disturbance history, interact to drive 2000s spruce beetle (Dendroctonus rufipennis) infestation of Engelmann spruce (Picea engelmannii) across the Southern Rocky Mountains; and 2) how previous spruce beetle infestation affects subsequent infestation across the Flat Tops Wilderness in northwestern Colorado, which experienced a severe landscape-scale spruce beetle infestation in the 1940s. We hypothesized that drought and warm temperatures would promote infestation, whereas small diameter and non-host trees, which may reflect past disturbance by spruce beetles, would inhibit infestation. Across the Southern Rocky Mountains, we found that climate and forest structure interacted to drive the 2000s infestation. Within the Flat Tops study area we found that stands infested in the 1940s were composed of higher proportions of small diameter and non-host trees ca. 60 years later. In this area, the 2000s infestation was constrained by a paucity of large diameter host trees (> 23 cm at diameter breast height), not climate. This suggests that there has not been sufficient time for trees to grow large enough to become susceptible to infestation. Concordantly, we found no overlap between areas affected by the 1940s infestation and the current infestation. These results show a severe spruce beetle infestation, which results in the depletion of susceptible hosts, can create a landscape template reducing the potential for future infestations.
53 citations
TL;DR: In all density classes of host plants tested, the infestation of scale insects decreased the chlorophyll and carotenoid content as well as the value of three indicators of photosynthetic activity.
Abstract: The aim of this experiment was to determine plant responses to Coccus hesperidum L. infestation on two host plants. Groups of five lemon and five fern plants were colonised by various numbers of mobile C. hesperidum instar nymphs. After 6 months, all scale insect individuals were counted on each plant. According to the insect density, the plants were divided into a five-degree series. In all density classes of host plants tested, the infestation of scale insects decreased the chlorophyll and carotenoid content as well as the value of three indicators of photosynthetic activity. The strongest decrease in the analysed pigments was observed for the smallest abundance of insects (first-class density) in lemon leaves and in second-class density in fern leaves. The strongest reactions of the chlorophyll fluorescence indicators were observed in density classes III and IV in the fern leaves and density classes IV or V in the lemon leaves. The reactions depended on the specific properties of plants and abundance of insects feeding on them.
50 citations
TL;DR: It is hypothesised that certain HIPVs, most likely monoterpenes, are involved in prey location by M. pygmaeus and have potential to manipulate the natural enemies of T. absoluta to enhance the control of this crop pest.
Abstract: One of the most damaging insect pests to tomato crops is the tomato leafminer, Tuta absoluta. Current control methods are not efficient at regulating this pest below the economic threshold, leading to the development of new strategies based on its natural enemies. In this study, we evaluated the ability of Macrolophus pygmaeus to discriminate T. absoluta-infested plants versus non-infested tomato plants. We subsequently collected volatile organic chemicals released by tomato plants under different levels of infestation, and identified the associated herbivore-induced plant volatiles (HIPVs). Behavioural assays were conducted in a double-choice olfactometer and flight tunnel. In both systems, M. pygmaeus was significantly attracted towards infested plants. Because distance attraction is likely to be mediated, at least partially, by volatile organic compounds, HIPVs were collected from healthy and infested plants using a dynamic volatile collection system. Volatile chemical profiles vary with the level of infestation; specifically, twice as many chemicals were identified under infestation by 20 T. absoluta larvae compared to healthy plants. A total of 35 compounds were identified, with β-phellandrene, 2-carene, β-caryophyllene, α-pinene and α-phellandrene representing 76–86 % of the total blend. The release of monoterpenes was strongly influenced by the level of caterpillar infestation, while the amount of sesquiterpenes did not vary significantly. We hypothesise that certain HIPVs, most likely monoterpenes, are involved in prey location by M. pygmaeus and have potential to manipulate the natural enemies of T. absoluta to enhance the control of this crop pest.
50 citations
TL;DR: Significant differences for leaf area, moisture, dry matter, ash, sugars, starch, and total carbohydrates were observed between the two types of leaves indicating a deep influence of the infestation on leaf functionality and on its photosynthetic capacity.
45 citations
TL;DR: The study highlights the interplay of biotic stressors within the terpenoid metabolism and identifies compounds emitted particularly in response to a multiple infestation (cyclohexadecane, dodecane, aromadendrene, and β-elemene).
Abstract: Tomato is susceptible to pest infestations by both spider mites and aphids. The effects of each individual pest on plants are known, whereas multiple-pest infestations have received little interest. We studied the effects of single- versus multiple-pest infestation by Tetranychus urticae and Myzus persicae on tomato biochemistry (Solanum lycopersicum) by combining a metabolomic approach and analyses of carotenoids using UHPLC-ToF-MS and volatiles using GC-MS. Plants responded differently to aphids and mites after 3 weeks of infestation, and a multiple infestation induced a specific metabolite composition in plants. In addition, we showed that volatiles emissions differed between the adaxial and abaxial leaf epidermes and identified compounds emitted particularly in response to a multiple infestation (cyclohexadecane, dodecane, aromadendrene, and β-elemene). Finally, the carotenoid concentrations in leaves and stems were more affected by multiple than single infestations. Our study highlights and discusses the interplay of biotic stressors within the terpenoid metabolism.
42 citations
TL;DR: Some varieties of flint corn and popcorn can be considered as potential maize varieties to be used to reduce postharvest loss of maize in tropical countries due to natural resistance to S. zeamais infestation.
36 citations
TL;DR: This study documented the first records of Dacus ciliatus (Loew) and Trirhithrum nigerrimum (Bezzi) in northern Ghana although both species have been previously reported in other parts of the country.
Abstract: An important aspect of fruit fly management is accurate information on the species and their host spectrum. Studies were conducted between October 2011 and September 2013 to determine the host range and species diversity of pest fruit flies in the northern savannah ecology of Ghana. Fruit samples from 80 potential host plants (wild and cultivated) were collected and incubated for fly emergence; 65 (81.5%) of the plant species were positive to fruit flies. From records in Africa, 11 plant species were reported to be new hosts to the African invader fly, Bactrocera invadens (Drew, Tsuruta and White, 2005). This study documented the first records of Dacus ciliatus (Loew) and Trirhithrum nigerrimum (Bezzi) in northern Ghana although both species have been previously reported in other parts of the country. Infestation by B. invadens was higher in the cultivated fruits; Ceratitis cosyra dominated in most wild fruits. Cucurbitaceae were mainly infested by three species of Dacus and Bactrocera cucurbitae, a specialized cucurbit feeder. Among the commercial fruit species, the highest infestations were observed in mango, tomato, sweet pepper and watermelon, whereas marula plum, soursop, tropical almond, sycamore fig, African peach, shea nut, persimmon, icacina and albarillo dominated the wild host flora. The widespread availability of host plants and the incidence of diverse fly species in the ecology call for particular attention to their impact on commercial fruits and the development of sustainable management strategies against these economically important pests in Ghana.
33 citations
TL;DR: It is confirmed that an intact beak is important for reducing ectoparasite infestations and preening in laying hens, and there was no correlation between preening and mite load.
TL;DR: The current state of knowledge of the behavioral effects of each chemical with respect to the various herbivorous insects and natural enemies is summarized and this information will facilitate quantitative studies on how different pest and beneficial insects respond to plant volatiles in polycultures.
Abstract: An experiment was conducted to manage the eggplant (brinjal) shoot and fruit borer Leucinodes orbonalis Guenee (Lepidoptera: Crambidae), the leafhopper Amrasca biguttula biguttula (Ishida) (Hemiptera: Cicadellidae), and the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) during kharif, the southwest monsoon season (Jul-Oct), in 2010 and 2011 at an experimental farm at the Division of Entomology, Indian Agricultural Research Institute, New Delhi. The experiment consisted of 7 different treatments with brinjal or eggplant ‘Pusa Kranti’, Solanum melongena L. (Solanales: Solanaceae), as the main crop and coriander, marigold or mint as intercrops, along with a border crop (maize or cowpea) acting as refuge crops. Treatment T1 (maize as border crop and coriander as intercrop) harbored the smallest cumulative mean leafhopper population (6.90 insects per 3 leaves per plant) and the next to smallest mean whitefly population (9.64 insects per 3 leaves per plant) during monsoon season of 2010 and 2011. Treatment T3 (maize as border crop and marigold as intercrop) was second best in reducing the leafhopper population (7.27 insects per 3 leaves per plant), while it was the best treatment in reducing the whitefly population (8.36 insects per 3 leaves per plant). The sole crop (T7) harbored the largest whitefly (20.17 insects per 3 leaves per plant) and leafhopper (12.61 insects per 3 leaves per plant) populations among the 7 treatments. The lowest mean percentage fruit infestation was recorded from treatment T1 (by number: 27.72; by weight: 27.81). All the treatments involving intercrops showed significantly lower percentage fruit infestation by L. orbonalis than eggplant alone (T7, control), which showed 37.73% infestation by number of fruits and 38.13% by weight of the fruits. The greatest mean number of coccinellids (1.25 per plant) and largest Shannon-Wiener indices were recorded from treatment T1 (maize and coriander). The smallest mean number of coccinellids (0.37 per plant) and smallest Shannon-Wiener indices were recorded from the sole crop control, T7. Various plant volatiles present in the intercrop were identified by the thermal desorption technique. Twenty one volatile compounds were present in coriander, 7 in marigold, and 18 in mint. The current state of knowledge of the behavioral effects (repellency, attractancy, no effect) of each chemical with respect the various herbivorous insects and natural enemies is summarized and this information will facilitate quantitative studies on how different pest and beneficial insects respond to plant volatiles in polycultures.
TL;DR: The incidence of infestation by emerald ash borer and lilac borer on white fringetree is compared to that of its Asian congener, Chinese fringETree, Chionanthus retusus, and a North American relative, devilwood, to determine the suitability of these hosts for EAB larvae.
Abstract: We compared the incidence of infestation by emerald ash borer (EAB) and lilac borer on white fringetree to that of its Asian congener, Chinese fringetree, Chionanthus retusus, and a North American relative, devilwood, Osmanthus americanus. We also conducted laboratory bioassays to determine the suitability of these hosts for EAB larvae. At Spring Grove Cemetery and Arboretum in Cincinnati, Ohio, 9 of 28 white fringetrees examined were infested by EAB. Most of the white fringetrees had lilac borer infestation, and most of the trees infested by EAB also had lilac borer infestation. None of the 11 Chinese fringetrees examined were infested by either EAB or lilac borer. Each of the five devilwood individuals examined was infested by lilac borer, but not EAB. At The Morton Arboretum in Lisle, Illinois, 7 of 16 white fringetrees examined were infested by EAB, while none of the seven Chinese fringetrees examined were infested by either insect. A 40-d bioassay confirmed that white fringetree was an acceptable host, producing fourth-instar larvae that were smaller than those produced on a highly susceptible cultivar of green ash, Fraxinus pennsylvanica. No larvae survived on Chinese fringetree, and neonates were largely incapable of feeding on it. Two larvae survived on devilwood, reaching the second instar and excavating extensive galleries. Future work should be aimed at biotic and abiotic factors influencing the susceptibility of white fringetree, as well as further examination of close relatives for their vulnerability to EAB.
TL;DR: Analysis of the spatiotemporal distribution of infested trees for a 5‐year period from 2008 to 2012 using a generalised linear model approach shows that spread and infestation risk were significantly affected by distance of suitable hosts from the nearest infested Trees, number of infestation trees in the surroundings, and annual variation.
Abstract: The Asian longhorned beetle (ALB), Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), is recognised as potentially one of the most damaging invasive insects in Europe and North America. International trade has increased the risk of accidental introduction of ALB. An eradication programme was initiated in Northeast Italy in June 2009, when an ALB infestation was discovered. The infestation was monitored by annual surveys of all host-tree species growing in the eradication area. Infested trees were cut down and chipped. This study analyses the spatiotemporal distribution of infested trees for a 5-year period from 2008 to 2012 using a generalised linear model approach. The results show that spread and infestation risk were significantly affected by (1) distance of suitable hosts from the nearest infested trees, (2) number of infested trees in the surroundings, and (3) annual variation. The significant differences in beetle dispersal between years reflect to some extent the onset of the eradication programme. The model allowed the estimation of arbitrary probability-based management boundaries surrounding ALB-infested trees. For example, the model estimated a 0.1% probability of attack on a suitable host tree 1 910 m from an existing attack.
TL;DR: The degree-day model based on minimum and maximum temperatures reliably described the population dynamics in the protected crop, and estimated the completion of 7.4 generations per year under open-field Mediterranean conditions.
Abstract: The population structure and dynamics of the tomato leafminer Tuta absoluta were investigated in a protected tomato crop and on potato and tomato crops and Solanum nigrum plants under open-field Mediterranean climatic conditions (Sardinia) by captures in pheromone-baited traps and visual inspection of host plants. In the greenhouse crop, male captures and leaf infestation were low in winter and increased steadily in spring up to 797.3 males/trap/week and 6.4 mines/leaf, respectively. Under open-field conditions, males were captured all year round with a peak in early September, concurrently with highest mean daily temperatures. Pest density in potato crops was very low (<0.3 mines/leaf), as well as on S. nigrum (0.16 mines/leaf). Conversely, high pest infestation was observed in tomato leaves (3.8 mines/leaf) and fruits (27% damaged fruits). Eggs, larvae and adults were detected over two consecutive winters, indicating that T. absoluta can develop continuously over the year under natural conditions. Parasitoids were recorded throughout the survey at low rates (≤16.1%). The most active beneficials were Necremnus tutae and Neochrysocharis formosa in protected and open-field crops, respectively. The tomato leafminer completed 6 generations in the greenhouse tomato crop during the winter-spring growing season, whereas in open-field crops the pest completed two generations on winter potato and 4-5 in spring-summer tomato. The degree-day model based on minimum and maximum temperatures reliably described the population dynamics in the protected crop, and estimated the completion of 7.4 generations per year under open-field Mediterranean conditions.
TL;DR: Evidence to prioritize rural households for improvement to prevent house infestation with Triatoma dimidiata in Central America is shown, and house wall materials and signs of infestation were among the most important predictive factors.
Abstract: The interruption of vectorial transmission of Chagas disease by Triatoma dimidiata in central America is a public health challenge that cannot be resolved by insecticide application alone. In this study, we collected information on previously known household risk factors for infestation in 11 villages and more than 2,000 houses in Guatemala, Honduras, and El Salvador, and we constructed multivariate models and used multimodel inference to evaluate their importance as predictors of infestation in the region. The models had moderate ability to predict infested houses (sensitivity, 0.32-0.54) and excellent ability to predict noninfested houses (specificity higher than 0.90). Predictive ability was improved by including random village effects and presence of signs of infestation (insect feces, eggs, and exuviae) as fixed effects. Multimodel inference results varied depending on factors included, but house wall materials (adobe, bajareque, and palopique) and signs of infestation were among the most important predictive factors. Reduced models were not supported suggesting that all factors contributed to predictions. Previous knowledge and information from this study show that we have evidence to prioritize rural households for improvement to prevent house infestation with Triatoma dimidiata in Central America. House improvement will most likely have other health co-benefits.
TL;DR: To determine its seasonal phenology, adult beetle longevity, density of successful emergence, infestation age and overwintering life history, field and laboratory studies were conducted on an A. glabripennis infestation in Northern Italy from 2010 to 2012.
Abstract: The Asian longhorn beetle Anoplophora glabripennis is highly polyphagous and widely spread over regions with different climates. Determining the key life-history traits is important for understanding how local conditions affect its successful establishment and to develop adaptive management strategies. 2 Field and laboratory studies were conducted from 2010 to 2012 on an A. glabripennis infestation in Northern Italy, aiming to determine its seasonal phenology, adult beetle longevity, density of successful emergence, infestation age and overwintering life history. 3 Adult beetle emerged from infested trees from 22 May to 28 June. Ninety percent of emergence was reached around 20 July. The first 1% of emergence was accurately predicted by an accumulated degree-day model. 4 In the laboratory, the mean longevity of males and females developed under natural conditions was 27.8 ± 1.7 and 24.9± 1.8 days, respectively. In northern Italy, A. glabripennis largely overwinter as mature larvae in the xylem. The mean density of exit holes was 24.0 ± 2.7 holes/m 2 of bark, with successful emergence from branches as small as 3.2 cm in diameter. Although the infestation was discovered in June 2009, the oldest exit hole found in infested trees dated from 2005.
TL;DR: The regulated area free of A. glabripennis was declared in early April 2013, after five years of negative survey results within the regulated area, and a private citizen found an adult beetle on a vehicle parked at his work site in an industrial area in Mississauga.
Abstract: The native range of the Asian longhorned beetle, Anoplophora glabripennisMotschulsky (Coleoptera: Cerambycidae), is limited to China and the Korean Peninsula (Lingafelter and Hoebeke 2002). For decades, wood infested by A. glabripennis had been used as packaging material or dunnage to transport goods exported from China (Haack and Cavey 1997; Haack 2006; Haack et al. 2010). Some of these larvae survived the trek and thus, populations of this polyphagous wood-borer arrived and established in several cities in North America and Europe (Hu et al. 2009; Haack et al. 2010). In September 2003, the Canadian Food Inspection Agency (CFIA) reported the discovery of an A. glabripennis breeding population at the boundary of Toronto and Vaughan (Hopkin et al. 2004). The agency implemented an eradication program against the beetle and established a regulated area of 152 km in January 2004. This program called for the removal of all infested trees and of all trees belonging to genera considered suitable for the complete development of the beetle that were within 400 m of an infested tree. In 2003, these genera were Acer L. (Sapindaceae), Aesculus L. (Sapindaceae), Albizia Durazz (Fabaceae), Betula L. (Betulaceae), Celtis L. (Cannabaceae), Platanus A. Dietrich (Platanaceae), Populus L. (Salicaceae), Salix L. (Salicaceae), Sorbus L. (Rosaceae), and Ulmus L. (Ulmaceae) (Haack et al. 2010). Upon completion of that treatment, the agency carried out continual intensive detection surveys of the regulated area and annual yet less intensive area-wide detection surveys outside the perimeter of the regulated area. The last infested tree was found in December 2007. The CFIA declared the regulated area free of A. glabripennis in early April 2013, after five years of negative survey results within the regulated area (www.inspection.gc. ca/about-the-cfia/newsroom/news-releases/2013-0405/eng/1365168144940/1365168154936). A few months later, another infestation was discovered in Ontario. On 13 August 2013, a private citizen found an adult beetle on his vehicle that was parked at his work site in an industrial area in Mississauga (43.6981° N, 79.6180° W). This parking lot was about 2 km outside the area that had been regulated between 2003 and 2013, nearly 10 km from the epicenter of the 2003 infestation, and slightly more than 7.5 km from the closest tree with an exit hole. The citizen recognized the beetle as the one
TL;DR: It is suggested that host plant infestation by aphids may induce production of secondary metabolites that deter B. tabaci from settling on its host plants, and also for manipulating WF behaviour to improve IPM in chilli.
Abstract: The sweetpotato whitefly (WF), Bemisia tabaci, is a major pest that damages a wide range of vegetable crops in Malaysia. WF infestation is influenced by a variety of factors, including previous infestation of the host plant by other insect pests. This study investigated the effects of previous infestation of host chilli plants by the green peach aphid (Myzus persicae) on the olfactory behavioural response of B. tabaci, using free-choice bioassay with a Y-tube olfactometer. We analysed volatile organic compounds (VOCs) emitted by non-infested and M. persicae-infested chilli plants using solid-phase microextraction and gas chromatography-mass spectrometry. Our results showed that female WFs preferred non-infested to pre-infested plants. Collection and analysis of volatile compounds emitted by infested plants confirmed that there were significant increases in the production of monoterpenes (cymene; 1,8-cineole), sesquiterpenes (β-cadinene, α-copaene), and methyl salicylate (MeSA) compared to non-infested plants. Our results suggest that host plant infestation by aphids may induce production of secondary metabolites that deter B. tabaci from settling on its host plants. These results provide important information for understanding WF host selection and dispersal among crops, and also for manipulating WF behaviour to improve IPM in chilli.
TL;DR: The obtained results show an important long lasting effect on house protection against triatomine infestation in a region of known pyrethroid resistant populations of T. infestans, as the result of the slow release of the active ingredients, protected by the formulation microcapsule.
Abstract: Triatoma infestans, the main vector of Trypanosoma cruzi (causative agent of Chagas disease) has been successfully eliminated over much of its original geographic distribution over the southern cone countries of South America. However, populations of the species are still infesting houses of rural communities of the Gran Chaco region of Argentina and Bolivia. This study reports for the first time a large-scale effect of a vector control intervention using a microencapsulated formulation of organophosphates and insect growth regulator on house infestation by T. infestans, in the southwestern region of Santa Cruz de la Sierra Department, within the Bolivian chaco. The vector control intervention included the treatment and entomological evaluation of 1626 individually coded and georeferenced houses with the microencapsulated formulation. House infestation by T. infestans was evaluated by active searches with fixed capture effort carried out before and after two, 16 and 32 months of the treatment application. House infestation prevalence was 30.5% before the intervention, spatially aggregated in two clusters of 38 and 25 localities that showed 41% and 38% house infestation by T. infestans. Infestation prevalence was reduced to 2.4% two months after the intervention and remained very low (1.7%) until the end of the study after 32 months of the control intervention, without any other additional vector control intervention. The obtained results show an important long lasting effect on house protection against triatomine infestation in a region of known pyrethroid resistant populations of T. infestans, as the result of the slow release of the active ingredients, protected by the formulation microcapsule.
TL;DR: To determine the prevalence of helminth infestation during pregnancy and the associated risks of adverse maternal and infant outcomes, a large number of women were surveyed in Northern Ireland.
TL;DR: Results suggest that total stand mortality demonstrated strong temporal dynamics and the magnitude of N mineralization and N₂O and CH₄ fluxes may continue to increase beyond the initial 5 yr of monitoring because litter-derived labile N will probably contribute to the second pulse of N Mineralization.
Abstract: The unprecedented scale of recent mountain pine beetle (Dendroctonus ponderosae, MPB) infestation in lodgepole pine (Pinus contorta ex Loudon var. latifolia Engelm. ex S. Watson) forests of western North America may significantly impact the role of forest soils as important sinks for global C and N. The aim of this study was to explain soil and litter N responses in stands experiencing total mortality during the first 5 yr of MPB outbreak. Four-year monitoring (2009–2012) of needlefall deposition, soil water-filled pore space (WFPS), NH₄, NO₃, potentially mineralizable N (PMN), dissolved organic N (DON), N₂O, and CH₄ was established in Medicine Bow National Forest in stands of different infestation histories (infested in 2007, 2008, and uninfested). Results suggest that total stand mortality demonstrated strong temporal dynamics. First-year soil responses included increases in PMN and were followed by WFPS and NH₄ increases in the second year, NO₃ increase in the third year, and DON increase in in the fourth year of the infestation. Litter NH₄ increased within 1 yr, but litter PMN, NO₃, and DON increased 3 yr after the infestation, suggesting enhanced litter decomposability. Soil N₂O and CH₄ fluxes also started to increase 4 yr after the infestation. These changes were indicative of ongoing disequilibrium for the period of at least 5 yr after MPB infestation. The magnitude of N mineralization and N₂O and CH₄ fluxes may continue to increase beyond the initial 5 yr of monitoring because litter-derived labile N will probably contribute to the second pulse of N mineralization.
TL;DR: This study has identified, for the first time, several potential metabolic pathways for acclimatization and defense mechanisms against BPH infestation in Thai Jasmine rice.
Abstract: Brown planthopper (BPH; Nilaparvata lugens) is a phloem feeding insect which is one of the most serious threats to rice crops in many countries throughout Asia. 1H NMR spectroscopy, combined with chemometrics, was used to analyze the polar metabolome from leaf extracts of Thai Jasmine rice (brown planthopper (BPH)-susceptible KD) and its BPH resistant isogenic lines (BPH-resistant IL7 and BPH-resistant+ IL308 varieties) with and without BPH infestation at various time points (days 1, 2, 3, 4 and 8). Physiological changes of the rice isogenic lines were different based on the quantitative trait loci of BPH resistance. Multivariate models were capable of distinguishing between the susceptible and the resistant rice varieties throughout the infestation. The concentration of 10 metabolites were significantly altered (p < 0.05) between the infested and the control groups of each examined rice variety. Metabolic pathway analysis suggested that BPH infestation could perturb transamination during the early stages of infestation (days 1–3) for all rice varieties. In addition, the IL7 and IL308 varieties responded earlier (day 3) than the KD variety (day 8) by perturbing amino acid metabolism, shikimate and gluconeogenesis pathways. By day 8 of the infestation, the KD cultivar responded by activating the amino acid-mediated-de novo pathway whereas the IL308 variety activated the purine and pyrimidine compound-mediated-salvage pathway for nucleotide biosynthesis. This study has identified, for the first time, several potential metabolic pathways for acclimatization and defense mechanisms against BPH infestation. These findings provide a valuable, first insight into BPH resistance mechanisms in Thai Jasmine rice.
TL;DR: It is suggested that aboveground whitefly infestation elicits systemic defence responses throughout the plant, providing new insights into insect-mediated leaf-root intra-communication and a framework to understand interactions between three organisms: whitefly, N. benthamiana and Agrobacterium.
Abstract: Summary � Agrobacterium tumefaciens causes crown gall disease. Although Agrobacterium can be popularly used for genetic engineering, the influence of aboveground insect infestation on Agrobacterium induced gall formation has not been investigated. � Nicotiana benthamiana leaves were exposed to a sucking insect (whitefly) infestation and benzothiadiazole (BTH) for 7 d, and these exposed plants were inoculated with a tumorigenic Agrobacterium strain. We evaluated, both in planta and in vitro, how whitefly infestation affects crown gall disease. � Whitefly-infested plants exhibited at least a two-fold reduction in gall formation on both stem and crown root. Silencing of isochorismate synthase 1 (ICS1), required for salicylic acid (SA) synthesis, compromised gall formation indicating an involvement of SA in whiteflyderived plant defence against Agrobacterium. Endogenous SA content was augmented in whitefly-infested plants upon Agrobacterium inoculation. In addition, SA concentration was three times higher in root exudates from whitefly-infested plants. As a consequence, Agrobacterium-mediated transformation of roots of whitefly-infested plants was clearly inhibited when compared to control plants. These results suggest that aboveground whitefly infestation elicits systemic defence responses throughout the plant. � Our findings provide new insights into insect-mediated leaf–root intra-communication and a framework to understand interactions between three organisms: whitefly, N. benthamiana and Agrobacterium.
TL;DR: Independent, direct negative density feedbacks on immunity and parasite exposure in adults are found, supporting the hypothesis of energy constraints and/or physiological stress acting on immunity at high density and highlighting the importance of investigating the pathways among host density, host immunity, and parasite infestation.
Abstract: When effective immune defenses against parasites are costly and resources limited, individuals are expected to alter their investment in immunity in response to the risk of infection. As an ecological factor that can affect both food abundance and parasite exposure, host density can play an important role in host immunity and host-parasite interactions. High levels of intraspecific competition for food and social stress at high host density may diminish immune defenses and increase host susceptibility to parasites. At the same time, for contagious and environmentally transmitted parasites, parasite exposure often increases with host density, whereas in mobile parasites that actively search for hosts, parasite exposure can decrease with host density due to the "encounter-dilution effect." To unravel these multiple and potentially opposing effects of host density on immunity, we manipulated density of the common lizard Zootoca vivipara and measured local inflammation in response to PHA injection and levels of infestation by the tick Ixodes ricinus, a mobile ectoparasite for which we expected an encounter-dilution effect to occur. Local inflammation strongly decreased with lizard density in adults, but not in yearlings. Tick infestation (abundance and prevalence) was negatively correlated with lizard density in both age classes. Using path analyses, we found independent, direct negative density feedbacks on immunity and parasite exposure in adults, supporting the hypothesis of energy constraints and/or physiological stress acting on immunity at high density. In contrast, for yearlings, the best path model showed that density diluted exposure to parasites, which themselves down-regulated immune defenses in lizards. These results highlight the importance of investigating the pathways among host density, host immunity, and parasite infestation, while accounting for relevant individual traits such as age.
TL;DR: In this paper, a subset of Bacillus spp, namely Bacillus flexus, B. subtilis, Bacillus megaterium and B. aryabhattai, was evaluated against the most devastating root-knot nematode, Meloidogyne incognita (Kofoid and White) Chitwood infestation and essential oil yield enhancement in Ocimum basilicum var. CIM-Soumya (Sweet basil).
Abstract: Despite the vast exploration of bioinoculants for disease resistance and crop yield enhancement, knowledge about their impact on quality and quantity of essential oil as well as induction of antioxidant is scarce, especially in medicinal and aromatic crops. In the present two-year field experimentation, a subset of Bacillus spp., namely Bacillus flexus, B. subtilis, B. megaterium and B. aryabhattai, was evaluated against the most devastating root-knot nematode, Meloidogyne incognita (Kofoid and White) Chitwood infestation and essential oil yield enhancement in Ocimum basilicum var. CIM-Soumya (Sweet basil). The plants treated with B. subtilis showed significant (P < 0.05) enhancement in fresh biomass (42%), essential oil content (121%), nutrient uptake (83%) and reduced root-knot infestation (54%) as compared to untreated control. The defence afforded by bioinoculants was observed based on augmentation of the phenolic (97%), flavonoid (93%), free radical scavenging activity (34%) and total antioxidant (33...
TL;DR: It is observed that infested bees are less involved in tending larvae and dealing with hive duties compared to their uninfested mates, and some hypotheses which could be tested using the infestation method presented here are drawn.
Abstract: Honeybee colonies (Apis mellifera) host a number of parasites, among which the mite Varroa destructor has been implicated in colony losses recorded around the world in recent years. Although many studies have been carried out on the direct and indirect damage caused by the mite to its host, the possible influence of mite infestation on the in-hive behaviour of honeybees has received little attention so far; moreover, to our knowledge, no behavioural study has been performed on adult bees infested during the pupal stage, which is when the mite causes most of its detrimental effects. In order to assess any possible consequence of infestation on the in-hive behaviour of honeybees, we carried out detailed observations on adult bees artificially infested during the pupal stage. We recorded a higher proportion of inactive bees among the infested ones; moreover, we observed that infested bees are less involved in tending larvae and dealing with hive duties compared to their uninfested mates. These results allow to draw some hypotheses which could be tested using the infestation method presented here.
TL;DR: The ticks distribution on the body surface of infested ruminants the highest infestation was found in the udder and tail (21 %) in cattle, ear (42.5 %) and tail in sheep and ear (63 %)and tail (17 %" in goats, while the lowest number of ticks inBody surface of ruminant was observed in the ear and shoulder (2 %).
Abstract: This survey was performed to find out the infestation rate of Ixodidae ticks in domestic ruminants in Ilam County during 21 March 2009 to 23 August 2009. Sampling was performed in 25 villages and 15 animal farm from different areas of this County. A total of 1,316 ticks were collected from 416 cattle, 208 sheep and 147 goats. The overall prevalence of ticks was recorded: 43, 23.5, and 49/6 % in cattle, sheep, and goats respectively. The number of ticks that collected from cattle, sheep, and goat were 328, 573, and 415 respectively. According to the host, Hyalomma anatolicum anatolicum (71.4 %), Hyalomma asiaticum asiaticum (17.6 %) and Rhipicephalus bursa (11 %) were collected from cattle. Hy. anatolicum (32.1 %), Rh. bursa (42.2 %), Rhipicephalus sanguineus (17.3 %) and Haemaphysalis inermis (8.4 %) were collected in sheep. Rh. bursa (41.5 %), Rh. sanguineus (43.2 %) and Ha. inermis (15.3 %) were observed in goats. In this study, ticks infestation rate of cattle, sheep and goat were (43 %), (23.5 %) and (49.6 %) respectively. In this survey the ticks distribution on the body surface of infested ruminants the highest infestation was found in the udder and tail (21 %) in cattle, ear (42.5 %) and tail (30 %) in sheep and ear (63 %) and tail (17 %) in goats. The lowest number of ticks in body surface of ruminants was observed in the ear and shoulder (2 %) in cattle, head and neck (2 %) in sheep and udder (7 %) in goats. Hy. anatolicum anatolicum, Rh. Sanguineus and Rh.bursa were dominant tick in domestic ruminants of Ilam County.
TL;DR: This report reports on ash regeneration and infestation at the epicentre of the initial EAB invasion in Canada (near Windsor, Ontario), and finds abundant ash regeneration in the impacted area up to 12 years after detection of the outbreak.
Abstract: The emerald ash borer (EAB), a wood-boring beetle native of Asia, has killed millions of ash trees in North America since its detection in 2002. The rapid spread of the infestation and the widespread distribution and importance of ash in North America, coupled with the genus’ high vulnerability raise the crucial question of ash regeneration capacity following EAB infestation and its potentially broad ecological implications. We report on ash regeneration and infestation at the epicentre of the initial EAB invasion in Canada (near Windsor, Ontario). Up to 12 years after detection of the outbreak, we found abundant ash regeneration in the impacted area. However, the likelihood of these stems reaching maturity appears low. Dissection of a subsample of saplings allowed us to confirm the presence of an active residual EAB population, with infestation in 19% of regenerating stems (including stems as small as 2 cm in basal diameter). A vigorous regenerating ash cohort comprising a large portion of stump resprout...
TL;DR: The results confirm that, even after correcting for temperature and salinity effects, in - festation pressure from salmon farms significantly increases the probability of lice infestation in wild salmonids, and found a signif- icant interaction between temperature and infestation pressure from Salmon farms.
Abstract: Ecological monitoring programmes should provide precise data to inform management, but the data quality is often limited by methodological challenges and the need for cost-effective sampling. Parasite infestations are particularly challenging to monitor due to complex interactions among hosts, parasites and the environment. In Norway, salmon lice infestations on wild salmonid fish have been mon- itored since 1992 to survey the potential transmission between farmed and wild salmonids. Here, we com- pared spatiotemporal variation in salmon lice levels with variations in local fjord conditions, including salinity, temperature and infestation pressure from salmon farms (measured as mean abundance of ma- ture female lice × number of farmed fish). We tested 3 different measures of infestation with different statis- tical properties. Our results confirm that, even after correcting for temperature and salinity effects, in - festation pressure from salmon farms significantly increases the probability of lice infestation in wild salmonids. The probability of infestation increases with fish body length, salmon farm infestation pres- sure and tem perature, and decreases with increasing freshwater influence. Furthermore, we found a signif- icant interaction between temperature and infestation pressure from salmon farms. When the infestation pressure from farms is low, temperature has a strong increasing effect on the probability of infestation, but as the infestation pressure from farms increases, tem- perature gradually becomes less important. The exact results vary somewhat depending on the measure of lice infestations used, but the same trend can be seen in all models. We discuss the statistical and biological complexities that make monitoring of salmon lice in wild populations challenging.