Characterization of a Peruvian isolate of Metarhizium anisopliae var. acridum, a pathogen of grasshoppers

The objective of this study was to characterize the Peruvian isolate of Metarhizium anisopliae var. acridum, CG 863, obtained from the grasshopper Schistocerca interrita, a crop pest in Peru. The characterization was done by comparing this isolate with two other ones of M. anisopliae var. acridum, from Brazil and Australia, and with an isolate of M. anisopliae var. anisopliae. The three M. anisopliae var. acridum isolates had similar growth profiles in agar plates at 25°C and 37°C, and similar RAPD patterns according to the analysis of three primers. However, regarding these parameters and conidial size, these isolates were very distinct when compared to M. anisopliae var. anisopliae isolate. Bioassays indicated that the Peruvian isolate is as pathogenic as the Brazilian isolate against nymphs of Rhammatocerus schistocercoides.

Cross talk between 2,4-diacetylphloroglucinol-producing biocontrol pseudomonads on wheat roots.

The performance of Pseudomonas biocontrol agents may be improved by applying mixtures of strains which are complementary in their capacity to suppress plant diseases. Here, we have chosen the combination of Pseudomonas fluorescens CHA0 with another well-characterized biocontrol agent, P. fluorescens Q2-87, as a model to study how these strains affect each other's expression of a biocontrol trait. In both strains, production of the antimicrobial compound 2,4-diacetylphloroglucinol (DAPG) is a crucial factor contributing to the suppression of root diseases. DAPG acts as a signaling compound inducing the expression of its own biosynthetic genes. Experimental setups were developed to investigate whether, when combining strains CHA0 and Q2-87, DAPG excreted by one strain may influence expression of DAPG-biosynthetic genes in the other strain in vitro and on the roots of wheat. DAPG production was monitored by observing the expression of lacZ fused to the biosynthetic gene phlA of the respective strain. Dual-culture assays in which the two strains were grown in liquid medium physically separated by a membrane revealed that Q2-87 but not its DAPG-negative mutant Q2-87::Tn5-1 strongly induced phlA expression in a DeltaphlA mutant of strain CHA0. In the same way, phlA expression in a Q2-87 background was induced by DAPG produced by CHA0. When coinoculated onto the roots of wheat seedlings grown under gnotobiotic conditions, strains Q2-87 and CHA0, but not their respective DAPG-negative mutants, were able to enhance phlA expression in each other. In summary, we have established that two nonrelated pseudomonads may stimulate each other in the expression of an antimicrobial compound important for biocontrol. This interpopulation communication occurs in the rhizosphere, i.e., at the site of pathogen inhibition, and is mediated by the antimicrobial compound itself acting as a signal exchanged between the two pseudomonads.

RpoN (sigma54) controls production of antifungal compounds and biocontrol activity in Pseudomonas fluorescens CHA0.

Pseudomonas fluorescens CHA0 is an effective biocontrol agent of root diseases caused by fungal pathogens. The strain produces the antibiotics 2,4-diacetylphloroglucinol (DAPG) and pyoluteorin (PLT) that make essential contributions to pathogen suppression. This study focused on the role of the sigma factor RpoN (sigma54) in regulation of antibiotic production and biocontrol activity in P. fluorescens. An rpoN in-frame-deletion mutant of CHAO had a delayed growth, was impaired in the utilization of several carbon and nitrogen sources, and was more sensitive to salt stress. The rpoN mutant was defective for flagella and displayed drastically reduced swimming and swarming motilities. Interestingly, the rpoN mutant showed a severalfold enhanced production of DAPG and expression of the biosynthetic gene phlA compared with the wild type and the mutant complemented with monocopy rpoN+. By contrast, loss of RpoN function resulted in markedly lowered PLT production and plt gene expression, suggesting that RpoN controls the balance of the two antibiotics in strain CHA0. In natural soil microcosms, the rpoN mutant was less effective in protecting cucumber from a root rot caused by Pythium ultimum. Remarkably, the mutant was not significantly impaired in its root colonization capacity, even at early stages of root infection by Pythium spp. Taken together, our results establish RpoN for the first time as a major regulator of biocontrol activity in Pseudomonas fluorescens.

Induced-feeding bioassays for detection of Bacillus thuringiensis insecticidal activity against Epilachna paenulata (Coleoptera)

The objective of this work was to establish and test the induced-feeding bioassay in order to detect Bacillus thuringiensis insecticidal activity against Epilachna paenulata (Coleoptera: Coccinellidae). Larvae were induced to swallow high concentrations of spore-crystal suspensions of seven exotic and 30 Argentine B. thuringiensis strains. The great majority of strains showed no toxicity to E. paenulata larvae, and observed mortality was lower than 30%. Induced-feeding bioassay is feasible, and should be used for prospecting strains that produce right combinations of Cry proteins needed to an efficient pest control.

Egg parasitoid wasps as natural enemies of the neotropical stink bug Dichelops melacanthus

The objective of this work was to determine the potential of five species of Scelionidae wasps - Telenomus podisi, Trissolcus basalis, Trissolcus urichi, Trissolcus teretis and Trissolcus brochymenae - as natural enemies of the neotropical stink bug Dichelops melacanthus, and to determine if the presence of eggs of other stink bug species influences the parasitism and development of the parasitoids. Two kinds of experiments were done in laboratory: without choice of hosts (eggs of D. melacanthus) and with choice (eggs of D. melacanthus and of Euschistus heros). Biological parameters, including proportion of parasitism, immature survivorship, progeny sex ratio, immature stage development period, and host preference were recorded. All the evaluated parasitoids can parasitize and develop on D. melacanthus eggs. The first choice of eggs did not influence the proportion of D. melacanthus eggs parasitized by Tr. basalis, Tr. teretis or Tr. brochymenae. However, D. melacanthus eggs as the first choice of Te. podisi and Tr. urichi increased, respectively, 9 and 14 times the chance for parasitism on eggs of this species. Behavioral and ecological aspects of parasitoids should be considered prior to their use in biological control programs.

Toxicity of allyl esters in insect cell lines and in Spodoptera littoralis larvae

We investigated the effects of five allyl esters, two aromatic (allyl cinnamate and allyl 2-furoate) and three aliphatic (allyl hexanoate, allyl heptanoate, and allyl octanoate) in established insect cell lines derived from different species and tissues. We studied embryonic cells of the fruit fly Drosophila melanogaster (S2) (Diptera) and the beet armyworm Spodoptera exigua (Se4) (Lepidoptera), fat body cells of the Colorado potato beetle Leptinotarsa decemlineata (CPB) (Coleoptera), ovarian cells of the silkmoth Bombyx mori (Bm5), and midgut cells of the spruce budworm Choristoneura fumiferana (CF203) (Lepidoptera). Cytotoxicity was determined with use of MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] and trypan blue. In addition, we tested the entomotoxic action of allyl cinnamate against the cotton leafworm Spodoptera littoralis .The median (50%) cytotoxic concentrations (EC50s) of the five allyl esters in the MTT bioassays ranged between 0.25 and 27 mM with significant differences among allyl esters (P = 0.0012), cell lines (P < 0.0001), and the allyl estercell line interaction (P < 0.0001). Allyl cinnamate was the most active product, and CF203 the most sensitive cell line. In the trypan blue bioassays, cytotoxicity was produced rapidly and followed the same trend observed in the MTT bioassay. In first instars of S. littoralis, allyl cinnamate killed all larvae at 0.25% in the diet after 1 day, while this happened in third instars after 5 days. The LC50 in first instars was 0.08%. In addition, larval weight gain was reduced (P < 0.05) after 1 day of feeding on diet with 0.05%. In conclusion, the data provide evidence of the significant but differential cytotoxicity among allyl esters in insect cells of different species and tissues. Midgut cells show high sensitivity, indicating the insect midgut as a primary target tissue. Allyl cinnamate caused rapid toxic effects in S. littoralis larvae at low concentrations, suggesting further potential for use in pest control.

Noctuidae-induced plant volatiles: current situation and prospects

Noctuids are phytophagous lepidopterans with some species causing significant damage to agriculture. The host plants, in turn, have developed defense mechanisms to cope with them, for instance chemical defenses. In this study we review the literature on plant volatiles induced by noctuids, and discuss the methodologies used to induce the production of volatiles that are usually employed in plant defense mechanisms. Future prospects involving this line of research in pest control are also discussed.

Aktiivisten magneettilaakereiden ohjauslaitteiston vaatimusmäärittely ja toteutus

Aktiivinen magneettilaakeri on järjestelmä joka mahdollistaa pyörivän kappaleen, esimerkiksi sähkökoneen roottorin, leijuttamisen magneettikentässä ilman fyysistä kontaktia vastakappaleiden välillä. Tekniikalla on joitain merkittäviä etuja muihin laakerointijärjestelmiin verrattuna erityisesti suurnopeuksisissa tai puhdastiloissa käytettävissä sähkökäytöissä. Magneettilaakereiden yleistymistä nopeuttaisi ja niiden hintaa laskisi mikäli laakereiden säätöön ja tehonsyöttöön voitaisiin käyttää standardeja teollisuusautomaatiolaitteita erityisesti tätä käyttötarkoitusta varten kehitettyjen laitteiden sijaan. Tässä työssä luodaan menetelmä määrittää vähimmäisvaatimukset aktiivisen magneettilaakerin säätöalgoritmien suorittamiseen käytetylle säätöjärjestelmälle ja anturoinnille sekä laakerin toimintaan tarvittavalle tehoelektroniikalle. Näiden vaatimusten perusteella luodaan katsaus soveltuviin laitteisiin ja kootaan esimerkkikokoonpanot kahdelle erilaiselle magneettilaakeroitavalle kohteelle. Lisäksi työssä esitellään LUT:ssa vuosina 2014-2015 kehitetty magneettilaakerin teholähdeprototyyppi ja selvitetään edellytykset käyttää laitetta laakerijärjestelmän osana.

Développement, application et validation d’une nouvelle stratégie de mesure des indicateurs biologiques de l’exposition aux pyréthrinoïdes et aux pyréthrines chez l’humain

Les pyréthrinoïdes et les pyréthrines sont des insecticides neurotoxiques auxquels on attribue également des effets néfastes sur les systèmes immunitaire, hormonal et reproducteur. Ils sont abondamment utilisés en agriculture, mais aussi en horticulture, en extermination et dans le traitement d’infestations parasitaires humaines et animales (gale, poux). Il y a donc un intérêt en santé environnementale à connaître l’ampleur de l’exposition humaine à ces pesticides. La mesure des métabolites urinaires des pyréthrinoïdes et des pyréthrines apparaît une approche de choix pour arriver à cette fin puisqu’elle permet, en théorie, d’obtenir un portrait global de l’exposition. Or,traditionnellement et par soucis de simplicité les concentrations volumiques ou ajustées pour la créatinine) de ces biomarqueurs dans des urines ponctuelles sont déterminées, mais l’effet de l’utilisation de ces unités sur la validité des estimations de dose quotidienne absorbée n’a jamais été vérifié. L’objectif général de cette thèse était donc de développer, appliquer et valider une nouvelle stratégie de mesure et d’analyse de biomarqueurs pour améliorer la précision et la fiabilité des évaluations de l’exposition individuelles et populationnelles aux pyréthrinoïdes et pyréthrines. Les objectifs spécifiques étaient : i) de caractériser l’exposition humaine à ces contaminants en région urbaine et rurale au Québec et ii) de comparer la validité de la nouvelle stratégie de mesure et d’analyse de biomarqueurs urinaires proposée avec les autres méthodes plus usuelles utilisées pour estimer l’exposition individuelle et populationnelle et les doses absorbées de pyréthrinoïdes. Des adultes et des enfants, recrutés dans la population de l’Île de Montréal et de la Montérégie ont recueilli leurs urines pendant une période d’au moins douze heures et complété un questionnaire documentant les sources potentielles d’exposition. Les quantités de métabolites de pyréthrinoïdes et pyréthrines (pmol) mesurées dans les urines ont été ajustées pour une période de douze heures exactement et pour le poids corporel. Les quantités excrétées en région urbaine ont été comparées à celles excrétées en région rurale et les données individuelles et populationnelles ont été comparées à celles qui auraient été obtenues si des concentrations volumiques ou ajustées pour la créatinine avaient été mesurées. Les résultats montrent que l’exposition à ces pesticides est ubiquiste puisque plus de 90% des participants excrétaient les principaux métabolites de pyréthrinoïdes et pyréthrines à un niveau supérieur au seuil de détection analytique. Les résultats suggèrent que l’alimentation pourrait être à l’origine de ce niveau de base puisque les autres sources d’exposition connues n’ont été que rarement rapportées. Au Québec, l’exposition en milieu rural apparaissait légèrement plus importante qu’en milieu urbain et certains facteurs d’exposition, comme l’utilisation de pesticides domestiques, ont été rapportés plus fréquemment en milieu rural. Enfin, il a été démontré que la mesure des concentrations volumiques ou ajustées pour la créatinine de biomarqueurs est une approche qui peut entraîner des biais importants (jusqu’à 500% d’erreur et plus) en particulier lors de l’évaluation de l’exposition individuelle. Il est évident que les autorités de santé publique et de santé environnementale employant des biomarqueurs urinaires afin d’évaluer l’exposition aux pyréthrinoïdes et aux pyréthrines (ainsi qu’à d’autres molécules ayant des demi-vies d’élimination similaire)devraient diriger leurs efforts vers la mesure des quantités excrétées pendant une période d’au moins douze heures pour obtenir un portrait le plus valide possible de l’exposition. Il serait aussi souhaitable de mieux documenter la toxicocinétique de ces molécules chez l’humain afin d’établir avec une plus grande confiance la relation entre les quantités excrétées de biomarqueurs et les doses absorbées de ces contaminants.

Processing, procurement and marketing of pepper with particular reference to co-operative sector

The present Study is designed to gather, record and analyse data on history of pepper, pepper production, procurement and marketing with particular reference to Kerala. The main emphasis is given to study the'role of cooperative sector with regard to procurement and export efforts and also the services rendered by cooperative sector agencies under MARKETFED and NAFED to pepper trade. The scope of the Study covers the botany, methods of cultivation, fertilizer application, pest control management and other related aspects of pepper. Taking into consideration Kerala's supremacy in pepper cultivation and production, detailed study of its production, procurement, internal and export marketing with reference to Kerala has been given importance. As Kerala accounts for 96 per cent1 of the pepper cultivation and 94 per cent of the pepper production, the present study is entirely confined to Kerala

Factors influencing the use of selected inputs in yam production in Nigeria and Ghana

In West Africa, yam can be an important crop to reduce poverty and hunger if Research and Development measures identify and properly engage its key production factors for enhanced outputs and better income. Data from 1400 households in Ghana and Nigeria were collected in a multistage random sampling survey (and complementary data from 76 farm family fields) with a structured questionnaire and qualitative interview questions. The results showed that yam is produced mainly with crude inputs/technologies to reduce high dependence on labour, seed production and control of pests and diseases. Yam is produced widely with purchased inputs including seed yam and hired labour; chemical fertiliser, herbicide and pesticides are less often used. Analyses of determinants of use of purchased inputs reveal three serious impediments to expansion in yam production: the increasing scarcity and high cost of hired labour, shortage of suitable land and poor farm roads. As employment opportunities for unskilled labour in urban centres are presently expanding, increased yam production will be hard to achieve without labour-saving inputs for at least some of the production tasks, especially seedbed preparation and weeding, and without improvement in infrastructure.

Optimización ambiental y sanitaria en los casinos del Club Campestre El Rancho en la ciudad de Bogotá

El plan de saneamiento básico empleado en el Club El Racho de la ciudad de Bogotá, busca primordialmente mejorar las operaciones dentro de los espacios de preparación de alimentos del club, brindando en si una serie de lineamientos y parámetros básicos para lograr un óptimo desarrollo del mismo. Dentro de este plan se estudian y se exponen una serie de fases que requieren no sólo una implementación adecuada, sino también un proceso de seguimiento posterior a dicha implementación, con el único objetivo de controlar y mitigar reacciones y posibles alteraciones del programa. Llevando a cabo programas de limpieza y desinfección, de manejo de residuos sólidos y de control de plagas en los casinos del club, se busca también, lograr una concientización general tanto en empleados como socios y demás usuarios de los establecimientos y así darle al plan de saneamiento básico una ruta exitosa que garantice, así mismo, un desarrollo sostenible y una responsabilidad social.

Functional benefits of predator species diversity depend on prey identity

1. Determining the functional significance of species diversity in natural enemy assemblages is a key step towards prediction of the likely impact of biodiversity loss on natural pest control processes. While the biological control literature contains examples in which increased natural enemy diversity hinders pest control, other studies have highlighted mechanisms where pest suppression is promoted by increased enemy diversity. 2. This study aimed to test whether increased predator species diversity results in higher rates of predation on two key, but contrasting, insect pest species commonly found in the rice ecosystems of south-east Asia. 3. Glasshouse experiments were undertaken in which four life stages of a planthopper (Nilaparvata lugens) and a moth (Marasmia patnalis) were caged with single or three-species combinations of generalist predators. 4. Generally, predation rates of the three-species assemblages exceeded expectation when attacking M. patnalis, but not when attacking N. lugens. In addition, a positive effect of increased predator species richness on overall predation rate was found with M. patnalis but not with N. lugens. 5. The results are consistent with theoretical predictions that morphological and behavioural differentiation among prey life stages promotes functional complementarity among predator species. This indicates that emergent species diversity effects in natural enemy assemblages are context dependent; they depend not only on the characteristics of the predators species, but on the identity of the species on which they prey.

The genetic basis of resistance to anticoagulants in rodents

Anticoagulant compounds, i.e., derivatives of either 4-hydroxycoumarin (e.g., warfarin, bromadiolone) or indane-1,3-dione (e.g., diphacinone, chlorophacinone), have been in worldwide use as rodenticides for > 50 years. These compounds inhibit blood coagulation by repression of the vitamin K reductase reaction (VKOR). Anticoagulant-resistant rodent populations have been reported from many countries and pose a considerable problem for pest control. Resistance is transmitted as an autosomal dominant trait although, until recently, the basic genetic mutation was unknown. Here, we report on the identification of eight different mutations in the VKORC1 gene in resistant laboratory strains of brown rats and house mice and in wild-caught brown rats from various locations in Europe with five of these mutations affecting only two amino acids (Tyr139Cys, Tyr139Ser, Tyr139Phe and Leu128Gln, Leu128Ser). By recombinant expression of VKORC1 constructs in HEK293 cells we demonstrate that mutations at Tyr139 confer resistance to warlarin at variable degrees while the other mutations, in addition, dramatically reduce VKOR activity. Our data strongly argue for at least seven independent mutation events in brown rats and two in mice. They suggest that mutations in VKORC1 are the genetic basis of anticoagulant resistance in wild populations of rodents, although the mutations alone do not explain all aspects of resistance that have been reported. We hypothesize that these mutations, apart from generating structural changes in the VKORC1 protein, may induce compensatory mechanisms to maintain blood clotting. Our findings provide the basis for a DNA-based field monitoring of anticoagulant resistance in rodents.