The possibilities for control of two‐spotted spider mite Tetranychus urticae on field‐grown strawberries in the UK by predatory mites

The potential of two species of predatory phytoseiid mites to control the two‐spotted spider mite, Tetranychus urticae, on unprotected field‐grown strawberries in the UK was investigated. Typhlodromus pyri, a native species, was able to control T. urticae in some circumstances, but was less effective under hot, dry conditions. Natural colonization by this species is likely to be too slow in plantations of 1–2 years life. Attempts to introduce this predator to strawberry fields on cut apple shoots were unsuccessful. The exotic predator Phytoseiulus persimilis, which is available from commercial sources, gave very good control of T. urticae when released onto strawberry plants in June. A release earlier in the year was less successful, so to prevent early build‐up of mites and possible plant damage it may sometimes be necessary to reduce spider mite numbers early in the year with an acaricide, before a later release of P. persimilis. The success of this integrated control strategy was demonstrated.     

The possibilities for control of two‐spotted spider mite tetranychus urticae on field‐grown strawberries in the UK by predatory mites

Numerous field trials have been undertaken in order to obtain a deeper understanding of the behavior (persistence, dispersion, etc.) of Bacillus thuringiensis serovar. israelensis (B.t.i.) formulations when treating rivers or streams for blackfly control. After an extensive sampling of water and natural substrates (periphyton, sediments, moss), freezing is a useful procedure to prevent enzymatic deterioration or bacterial growth in samples before bioassays are to be performed. Using Aedes triseriatus neonate larvae, we quantified the effect on potency of freezing and thawing of B.t.i. suspensions at operational field concentrations. In addition, as samples varied in their content of natural substrates we tested the hypothesis that the presence of such suspended solids affected the mortality response of larvae. Our results showed that these parameters are of significant importance and should be accounted for when comparing bioassays performed on previously frozen or turbid samples.     

Efficacy,prey stage preference and optimum predator–prey ratio of the predatory mite,Neoseiulus longispinosus Evans (Acari: Phytoseiidae) to control the red spider mite,Oligonychus coffeae Nietner (Acari: Tetranychidae) infesting tea

The predatory mite, N. longispinosus preys up on red spider mite, O. coffeae infesting tea in south India. An attempt has been made to determine the predatory potential, prey stage preference and optimum predator–prey ratio of N. longispinosus under laboratory and green house conditions. When 50 adult female O. coffeae were given, the number of adults reduced by eight days along with an increase in the number of predators. The larvae hatched from the eggs laid by O. coffeae were fed by predatory mite. N. longispinosus preyed up on all life stages with a preference to larvae and nymphs of red spider mite. Predator–prey ratios of 1:33 and 1:50 were effective in lab, and 1:25 was found to be effective in green house. These results revealed that N. longispinosus could be used as a successful biocontrol candidate of O. coffeae in tea through augmentation or mass rearing and field release.     

Assessment of the efficacy of parasiticides for the control of tick infection in dogs under field conditions: what's new?

For their biological and ecological characteristics, ticks are vectors of the widest variety of pathogens causing tick-borne diseases (TBDs). Little information is available about the ways in which time spent by ticks to feed on hosts, transmission times and TBD prevention are related and it is exclusively limited to laboratory reports on adult stages. In particular, the time required by immature stages to transmit pathogens has not been determined for most TBDs. Considering their importance for animal and human health, effective control of immature ticks is advisable to reduce the damage ticks cause. Recently, the efficacy of a combination of imidacloprid 10%/permethrin 50% was compared with that of fipronil 10%/S-methoprene 9% against ticks when administered to naturally infected dogs. A semi-quantitative method was used to assess the methodological parameters to calculate drug efficacy on immature stages. On adult ticks, the efficacy of both products was high and overall very similar, whereas for the immature stages the combination of imidacloprid 10% and permethrin 50% had a higher efficacy than fipronil 10% and methoprene 9% throughout the observation period (statistically significant difference on day + 28 only). The semi-quantitative method proposed for the evaluation of immature stages can be considered a useful tool for calculating the efficacy of a drug in the field. Due the important role of immatures in the spread of TBDs, the immature tick load should be calculated to assess the efficacy of acaricidal products both under laboratory and field conditions.     

Development, long-term survival, and the maintenance of fertility in Neoseiulus californicus (Acari: Phytoseiidae) reared on an artificial diet

The effectiveness of non-prey food items, such as pollen, honeydew, and microbes, in maintaining phytoseiid mite populations is widely accepted. However, the availability of such naturally occurring non-prey foods varies with the season and surrounding environment; thus, it is difficult to manipulate and maintain supplies of these food sources. A great deal of research has examined the development and reproduction of phytoseiid mites on artificial diets. Although phytoseiid mites frequently develop, several studies have detected low fecundities of adult females reared on artificial diets. Therefore, the use of artificial diets for commercial propagation is often difficult. However, the potential of artificial diets to maintain phytoseiid mite populations has not yet been evaluated. In this study, we investigated the developmental success and survival of Neoseiulus californicus (McGregor) on an artificial diet. This mite may be one of the most effective phytoseiid species used in agricultural systems for the control of spider mites. N. californicus successfully developed on the artificial diets: 93.5-100% of individuals reached adulthood 4-7 days after hatching. The survival rates of gravid adult females maintained on the AD-1 artificial diet composed of yeast components, saccharides, and egg yolk at 25 degrees C were 100, 80, and 48.9% over 36, 60, and 90 days, respectively. Moreover, >80% of the surviving females maintained on AD-1 for 36 or 60 days laid eggs after being switched to a diet of the spider mite Tetranychus urticae Koch, although they had laid few eggs during the maintenance periods on the artificial diet. Our results indicate that artificial diets can serve as a potentially useful food source for the long-term maintenance of N. californicus populations.     

Effects of inoculation methods on the incidence of ear-cockle and ‘tundu’ on wheat under field conditions

Wheat,Triticum aestivum L. cv. Mexipak was artificially inoculated withAnguina tritici (Steinb.) under field conditions. Nematode inocula: 0, 0.1, 0.2 and 0.3 g of seed galls/50 seeds or, germinated seeds of wheat (sown in a 1-m long row) were either added as intact seed galls or as a suspension of 2nd stage juveniles. Inoculation of ungerminated seeds with juveniles produced the highest incidence of ear-cockle disease. Whereas, intact seed galls inocula produced the highest incidence of tundu disease. Ear-cockle incidence was always greater than that of tundu at all treatments. The highest reduction in grain yield was associated with the treatments that caused the highest incidence of tundu disease.     

Plant spatial distribution and predator–prey ratio affect biological control of the twospotted spider mite Tetranychus urticae (Acari: Tetranychidae) by the predatory mite Phytoseiulus persimilis (Acari: Phytoseiidae)

A greenhouse experiment was conducted to determine the effect of plant spacing and predator–prey ratio on dispersal and foraging efficiency of the predatory mite, Phytoseiulus persimilis, on the twospotted spider mite, Tetranychus urticae. When predators were released at the end of spider mite-infested arrays of lima bean plants that had either no spacing or two different patterns of spacing among plant rows, plant damage was uniformly low throughout the experiment at both predator–prey ratios (1:10 and 3:10) in the treatment with no spacing. In contrast, damage was higher in both treatments where plant rows were interrupted by spacing. At the 1:10 ratio, more plants closer to the predator release point experienced moderate damage than at the 3:10 ratio where only the plant rows farthest from the release point had unacceptable damage. Our findings suggest that point releases of P. persimilis at the standard 1:10 predator–prey ratio should be effective within a diameter of at least 65?cm on mite-infested patches of plants where pots are touching. However, if gaps in plant rows exist, even large numbers of predators may not be sufficient to protect parts of the crop unless predators are released at shorter fixed points in the greenhouse crop.     

The diel imprint of leaf metabolism on the δ13 C signal of soil respiration under control and drought conditions

Recent (13) CO(2) canopy pulse chase labeling studies revealed that photosynthesis influences the carbon isotopic composition of soil respired CO(2) (δ(13) C(SR)) even on a diel timescale. However, the driving mechanisms underlying these short-term responses remain unclear, in particular under drought conditions. The gas exchange of CO(2) isotopes of canopy and soil was monitored in drought/nondrought-stressed beech (Fagus sylvatica) saplings after (13) CO(2) canopy pulse labeling. A combined canopy/soil chamber system with gas-tight separated soil and canopy compartments was coupled to a laser spectrometer measuring mixing ratios and isotopic composition of CO(2) in air at high temporal resolution. The measured δ(13) C(SR) signal was then explained and substantiated by a mechanistic carbon allocation model. Leaf metabolism had a strong imprint on diel cycles in control plants, as a result of an alternating substrate supply switching between sugar and transient starch. By contrast, diel cycles in drought-stressed plants were determined by the relative contributions of autotrophic and heterotrophic respiration throughout the day. Drought reduced the speed of the link between photosynthesis and soil respiration by a factor of c. 2.5, depending on the photosynthetic rate. Drought slows the coupling between photosynthesis and soil respiration and alters the underlying mechanism causing diel variations of δ(13) C(SR).     

Effect of breeding season on fertility of sheep following estrus synchronization and fixed-time artificial insemination under field conditions in semi-arid tropical region

Accelerated lambing system is heavily reliant on reproductive technologies meant to enable off the season breeding in sheep. Therefore, the present study was programmed to assess the effect of breeding season (BS) on fertility of sheep following estrus synchronization (ES) and fixed time artificial insemination (FTAI). A total of 248 and 365 ewes were synchronized and inseminated during the BS (Febuary–March and July–September) and non-breeding season (NBS) respectively, during 2012–14. Synchronization of estrus was done by AVIKESIL-S, intra-vaginal progesterone sponges kept in situ in vagina for 12 days. 200 IU eCG was administered intramuscularly on 12th day after sponge withdrawal. FTAI was performed twice in ewes exhibiting signs of estrus at 48 and 56h after sponge removal, using liquid chilled semen of Patanwadi/Malpura rams containing 100 million sperm. Breeding season had no significant (p<0.05) effect on estrus synchronization. The estrous responses during the BS and NBS were 84.68% and 83.29% respectively. The lambing percentage during BS was 66.67%, which is significantly (p<0.05) higher than the lambing percentage of NBS (57.57%). Although, the lambing percentage in NBS maneuvered ewes were lower than the BS ewes but still the technology can be used to offset the effect of anestrus and to augment production in sheep.     

Evaluation of the effect of accounting method,IPCC v. LCA,on grass-based and confinement dairy systems’ greenhouse gas emissions

Life cycle assessment (LCA) and the Intergovernmental Panel on Climate Change (IPCC) guideline methodology, which are the principal greenhouse gas (GHG) quantification methods, were evaluated in this study using a dairy farm GHG model. The model was applied to estimate GHG emissions from two contrasting dairy systems: a seasonal calving pasture-based dairy farm and a total confinement dairy system. Data used to quantify emissions from these systems originated from a research study carried out over a 1-year period in Ireland. The genetic merit of cows modelled was similar for both systems. Total mixed ration was fed in the Confinement system, whereas grazed grass was mainly fed in the grass-based system. GHG emissions from these systems were quantified per unit of product and area. The results of both methods showed that the dairy system that emitted the lowest GHG emissions per unit area did not necessarily emit the lowest GHG emissions possible for a given level of product. Consequently, a recommendation from this study is that GHG emissions be evaluated per unit of product given the growing affluent human population and increasing demand for dairy products. The IPCC and LCA methods ranked dairy systems’ GHG emissions differently. For instance, the IPCC method quantified that the Confinement system reduced GHG emissions per unit of product by 8% compared with the grass-based system, but the LCA approach calculated that the Confinement system increased emissions by 16% when off-farm emissions associated with primary dairy production were included. Thus, GHG emissions should be quantified using approaches that quantify the total GHG emissions associated with the production system, so as to determine whether the dairy system was causing emissions displacement. The IPCC and LCA methods were also used in this study to simulate, through a dairy farm GHG model, what effect management changes within both production systems have on GHG emissions. The findings suggest that single changes have a small mitigating effect on GHG emissions (<5%), except for strategies used to control emissions from manure storage in the Confinement system (14% to 24%). However, when several management strategies were combined, GHG emissions per unit of product could be reduced significantly (15% to 30%). The LCA method was identified as the preferred approach to assess the effect of management changes on GHG emissions, but the analysis indicated that further standardisation of the approach is needed given the sensitivity of the approach to allocation decisions regarding milk and meat.     

Is the predatory mite <Emphasis Type="Italic">Kampimodromus aberrans</Emphasis> a candidate for the control of phytophagous mites in European apple orchards?

The most important biocontrol agents of phytophagous mites (mainly Tetranychidae) in European apple orchards are the predatory mites Amblyseius andersoni, Typhlodromus pyri and Euseius finlandicus (Phytoseiidae). A similar situation is found in Trentino (north-eastern Italy), an important apple production area in Europe. Another phytoseiid mite, Kampimodromus aberrans, can be dominant in neglected fruit orchards but is rare in commercial orchards because of its susceptibility to pesticides. However, pesticide resistant strains of K. aberrans have recently been found in vineyards. In the late 1990s, one of these resistant strains was successfully released on an experimental farm in Trentino. Kampimodromus aberrans spread to an apple orchard, despite the fact that it was colonized by T. pyri, A. andersoni and E. finlandicus, and became the dominant species. Since K. aberrans’ colonization appeared to be affected by apple cultivars, experiments were conducted on potted plants of three selected apple cultivars (Golden Delicious, Red Chief, Reinette du Canada). The results stressed the effect of cultivars on apple colonization by K. aberrans and suggested the role of leaf morphology in influencing this phenomenon. Field releases of K. aberrans were successfully performed in four commercial apple orchards. The incidence of K. aberrans in the total phytoseiid population increased over time and the predator became dominant in the season following its release in two orchards. Kampimodromus aberrans persists in these orchards as the dominant species. The adaptation of K. aberrans to varying environmental conditions, its tolerance to pesticides, and its competitiveness towards other phytoseiid species suggest a potential role of this species in the biological control of phytophagous mites in European apple orchards. Handling editor: Eric Lucas.     

Neoseiulus idaeus (Acari: Phytoseiidae) as a potential biocontrol agent of the two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae) in papaya: performance on different prey stage – host plant combinations

Development, reproduction, and life table parameters of the phytoseiid mite Neoseiulus idaeus Denmark & Muma preying on various stages of Tetranychus urticae Koch fed on papaya or snap bean plant were studied at 25 ± 2°C, 77 ± 2% RH and 12L:12D photoperiod. Most characteristics of the predator, including the duration of the immature stages, preoviposition and oviposition periods, and female longevity did not differ significantly among the different food combinations. During the adult stage, N. idaeus females survived up to 14 days. The net reproductive rate, the mean generation time, and the intrinsic rate of natural increase of N. idaeus were very similar on all T. urticae stage – host plant combinations, ranging from 5.15 to 6.61 females, 10.15 to 12.62 days, and 0.150 to 0.168, respectively. These results indicate that T. urticae reared either on papaya or snap bean is an adequate prey for the development and reproduction of N. idaeus. Moreover, the current findings demonstrate that the host plant of T. urticae did not affect the predator. The implications of these results for the success of N. idaeus as a biological control agent of T. urticae in papaya orchards are discussed.     

Outbreaks of Trialeurodes vaporariorum (West.) (Hemiptera: Aleyrodidae) under field conditions in the State of São Paulo, Brazil

Trialeurodes vaporariorum (West.) is a pest of greenhouse vegetables and ornamentals and infests crops in Europe and in the American continent. In Brazil, just a few cases are known on economic crops, being all restricted to greenhouse crops. In 2003, in Itatiba and neighboring localities of State of S?o Paulo, Brazil, field infestations of T. vaporariorum were observed, mainly on tomato and green bean. So far, whitefly infestation in this area expanded to squash and kale also. Field studies are needed for determining interactions of T. vaporariorum with plants and natural enemies, injury levels, and methods of control.     

UV hazard on a summer’s day under Mediterranean conditions, and the protective role of a beach umbrella

Mediterranean beaches are very crowded during summer and, because of the high values of solar UV radiation, the potential risk for human health is relevant. In this study, all-day measurements of biologically effective global and diffuse UV radiation for skin (UVBE_eryt) and eye (UVBE_pker, UVBE_pconj, UVBE_cat) disorders were carried out on differently tilted surfaces on a summers day on a Mediterranean beach. The role played by beach umbrellas in protection from excessive sun exposure was also investigated. Erythema, photokeratitis and cataract seem to require almost the same exposure time to reach the risk threshold dose. Under full sunlight, the highest global and diffuse UV values are reached on surfaces normally oriented towards sunlight and on horizontal surfaces, respectively. Over vertical surfaces, at this northern hemisphere site, global and diffuse UV radiation reaches maxima values in the south-facing direction around noon, while maxima values are reached early in the morning and late in the afternoon over surfaces facing east and west, respectively. The quality of the beach umbrellas protection (efficiency in blocking solar UV radiation) varies with surface orientation; the highest efficiency for our specific site and geometrical conditions occurs over horizontal surfaces, with efficiency being least over vertical surfaces when incident radiation values are still relevant.     

Effects of a lipid environment on the fibrillogenic pathway of the N-terminal polypeptide of human apolipoprotein A-I, responsible for in vivo amyloid fibril formation

In amyloidosis associated with apolipoprotein A-I (ApoA-I), heart amyloid deposits are mainly constituted by the 93-residue ApoA-I N-terminal region. A recombinant form of the amyloidogenic polypeptide, named [1-93]ApoA-I, shares conformational properties and aggregation propensity with its natural counterpart. The polypeptide, predominantly in a random coil state at pH 8.0, following acidification to pH 4.0 adopts a helical/molten globule transient state, which leads to formation of aggregates. Here we provide evidence that fibrillogenesis occurs also in physiologic-like conditions. At pH 6.4, [1-93]ApoA-I was found to assume predominantly an α-helical state, which undergoes aggregation at 37°C over time at a lower rate than at pH 4.0. After 7 days at pH 6.4, protofibrils were observed by atomic force microscopy (AFM). Using a multidisciplinary approach, including circular dichroism (CD), fluorescence, electrophoretic, and AFM analyses, we investigated the effects of a lipid environment on the conformational state and aggregation propensity of [1-93]ApoA-I. Following addition of the lipid-mimicking detergent Triton X-100, the polypeptide was found to be in a helical state at both pH 8.0 and 6.4, with no conformational transition occurring upon acidification. These helical conformers are stable and do not generate aggregated species, as observed by AFM after 21 days. Similarly, analyses of the effects of cholesterol demonstrated that this natural ApoA-I ligand induces formation of α-helix at physiological concentrations at both pH 8.0 and 6.4. Zwitterionic, positively charged, and negatively charged liposomes were found to affect [1-93]ApoA-I conformation, inducing helical species. Our data support the idea that lipids play a key role in [1-93]ApoA-I aggregation in vivo.     

Assessing the control/eradication of an invasive species,the American mink,based on field data; how much would it cost?

Biological invasions are an important cause of biodiversity loss, American mink being one of the worst invasive species in Europe. We performed a 13-week control program of the species in the Butron river system (Northern Spain), where a natural population of the European mink is found. Three population estimates were considered: an absolute minimum, an intermediate scenario and a pessimistic one (n = 35, 49 and 70 animals, respectively). After 2,242 cage trap-nights, trapping success varied from 44 to 89% of these estimates. In addition, we evaluated the costs of eradicating the estimated populations; costs ranged between 652.5 and 2,970 € per mink, and would rise up to 83,462 € for the intermediate estimate under an exponential function linking captures and costs, or ca. 172.500 € to capture the highest estimate under a log-function. The implications of these numbers for the design and implementation of future control projects are discussed.     

Effects of conditions for obtaining sporangiospores of the inoculum on the morphology and productivity of the fungus Mucor circinelloides var. lusitanicus 12 M, a producer of γ-linolenic acid

Effects of the lipid composition of sporangiospores of the fungus Mucor circinelloides var. lusitanicus 12 M, obtained within diverse time frames using distinct nutrient media, on the morphology of the fungus in submerged cultures, the yield of the biomass, and its content of g-linolenic acid have been studied. The levels of base phospholipids and individual fractions of neutral lipids in sporangiospores correlated with the character of their germination. The spores that were characterized by a high rate of germination and gave rise to a well-developed mycelium contained more phosphatidylcholine and phosphatidylserine, but the level of diacylglycerols was low. The increase in diacylglycerols, free fatty acids, and sterols in lipids of sporangiospores of the inoculate was associated with deterioration in mycelium development, dimorphism, and a decreasing yield of the biomass of the fungus.