Blackshaw Research and Consultancy

Devon, United Kingdom

Blackshaw Research and Consultancy

Devon, United Kingdom
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Blackshaw R.P.,Blackshaw Research and Consultancy | van Herk W.G.,Agriculture and Agri Food Canada | Vernon R.S.,Agriculture and Agri Food Canada
Agricultural and Forest Entomology | Year: 2017

A study was conducted to determine the attractive range of traps baited with Agriotes obscurus pheromone to male beetles in both still air and wind conditions. This information is crucial for evaluating the potential of mass trapping when aiming to reduce beetle populations. Groups of 10 beetles were released at 14 points spaced 1m apart along a linear track, at one end of which was a pheromone and wind source. Beetle response to the pheromone and/or wind was recorded 150s after release and characterized as orienting either towards or away from the pheromone and/or wind source. Data analysis indicated the attraction range of the sex pheromone is <5m in still air, which is considerably lower than estimates from previous studies and emphasizes the challenge of mass trapping this species in the field. The attraction range increased when there was air flow. Unexpectedly, not all male beetles respond to the pheromone, and beetles are inclined to move downwind even in the presence of pheromone. The latter finding suggests that wind direction may influence beetle dispersal and mate finding in the field. The implications of these results for determining the efficacy of mass trapping as a management approach are discussed. © 2017 The Royal Entomological Society.

Rutgers M.,National Institute for Public Health and the Environment RIVM | Orgiazzi A.,European Commission - Joint Research Center Ispra | Gardi C.,European Commission - Joint Research Center Ispra | Gardi C.,University of Parma | And 25 more authors.
Applied Soil Ecology | Year: 2016

Existing data sets on earthworm communities in Europe were collected, harmonized, collated, modelled and depicted on a soil biodiversity map. Digital Soil Mapping was applied using multiple regressions relating relatively low density earthworm community data to soil characteristics, land use, vegetation and climate factors (covariables) with a greater spatial resolution. Statistically significant relationships were used to build habitat-response models for maps depicting earthworm abundance and species diversity. While a good number of environmental predictors were significant in multiple regressions, geographical factors alone seem to be less relevant than climatic factors. Despite differing sampling protocols across the investigated European countries, land use and geological history were the most relevant factors determining the demography and diversity of the earthworms. Case studies from country-specific data sets (France, Germany, Ireland and The Netherlands) demonstrated the importance and efficiency of large databases for the detection of large spatial patterns that could be subsequently applied at smaller (local) scales. © 2015 Elsevier B.V.

Pope T.,Harper Adams University College | Gundalai E.,Harper Adams University College | Elliott L.,Harper Adams University College | Blackshaw R.,Blackshaw Research and Consultancy | And 5 more authors.
Journal of Berry Research | Year: 2015

BACKGROUND: Vine weevil (Otiorhynchus sulcatus) is a major pest of soft fruit and ornamental crops. There is an urgent needto improve control of vine weevil and in particular to provide growers with effective Integrated Pest Management-compatible controls with which to target the adult stage of this pest. One approach would be to exploit the behaviour of adult vine weevil to disseminate spores of an entomopathogenic fungus placed within the crop environment in artificial refuges. To be effective this approach requires that the weevils move through the crop environment and in doing so spread the pathogen from the artificial refuges. OBJECTIVE: Use passive radio frequency identification (RFID) tags to study the movement of adult vine weevil within crop environments. METHOD: A series of laboratory bioassays were completed in which the effect of attaching RFID tags using a thermoplastic or a cyanoacrylate adhesive on survival and movement, on both horizontal and vertical surfaces, of adult vine weevil was determined. An outdoor field experiment was then completed at Harper Adams University in order to test the potential of this technique for studying vine weevil movement within crop environments. RESULTS: Attaching RFID tags using the thermoplastic adhesive did not result in any weevil deaths over a 21 day period. In contrast, just over half (53%) of the weevils to which the RFID tag was attached using the cyanoacrylate adhesive died over the same period. The mean of weevil horizontal movement speed was significantly slower when an RFID tag was attached using a thermoplastic (1.01 cm/s) or a cyanoacrylate (0.29 cm/s) adhesive compared with untagged weevils (1.83 cm/s). However, weevils that were tagged using the thermoplastic adhesive were significantly faster than weevils tagged using the cyanoacrylate adhesive. Mean vertical movement speed was also significantly slower when weevils were tagged using the thermoplastic adhesive (0.18 cm/s) compared with untagged weevils (0.37 cm/s). Weevils tagged using the cyanoacrylate adhesive were unable to climb vertical surfaces. In the field experiment, weevils moved away from their release points. Nine days after the start of the experiment weevils were on average 3.38m from their release points indicating a speed of movement of 0.38 m/day. The mean distance of movement from their release points did not increase further during the rest of the experimental period, but remained relatively constant at between 2.50 and 3.28 m. As such, for weevils that remained within the crop environment, there is no evidence of dispersal behaviour, with movement behaviour observed more likely to be driven by resource utilisation. However, not all weevils remained within the crop area. Indeed, 15 (38%) of released weevils and/or RFID tags left the crop area, indicating possible long range dispersal by these individuals or evidence of predation of the weevils. A total of 11 (28%) of the RFID tagged weevils released into the crop were recovered alive and with the tag still attached after 35 days. These weevils were estimated to have moved a distances of between 2.65 and 17.30m (average distance moved 7.50 m) during this period. These distances are likely to underestimate the distance moved by each weevil as they assume that each weevil took the most direct route between each point and did not move other than this. In total eight of the RFID-tagged weevils moved both along and between rows of strawberry grow-bags. At the start of the experiment the 11 RFID tagged weevils occupied 11 (14%) of the strawberry grow-bags. If these weevils took the most direct route between each position within the crop where they were detected these weevils would have crossed, and potentially laid eggs in, 44 (58%) of the grow-bags during the 35 days of the experiment. If they had taken a more indirect route the weevils could have potentially laid eggs in a higher number of the grow-bags. CONCLUSIONS: Results presented here indicate that RFID tags can be used to study the movement of vine weevil adults within crop environments. However, the weight and size of currently available tags significantly slows the movement of weevils under laboratory conditions and frequency of detection may affect estimates of actual distance moved. Despite this, the rate at which vine weevil dispersed through the strawberry crop was comparable to the speed of movement recorded previously by others when weevils were released into an urban environment. Use of RFID tags also resulted in detection rates far higher than those reported in studies by others using traditional mark-release-recapture techniques. Use of RFID tags in the present study indicates that adult vine weevil have the potential to disperse spores of a suitable entomopathogenic fungus from artificial refuges throughout the crop environment. Use of this technique could also be applied to investigate the effect of other plant protection products as well as the impact of different cropping systems on vine weevil movement and survival. © 2015 - IOS Press and the authors. All rights reserved.

Murchie A.K.,Agri Food and Biosciences Institute of Northern Ireland | Blackshaw R.P.,Blackshaw Research and Consultancy | Gordon A.W.,Agri Food and Biosciences Institute of Northern Ireland | Christie P.,Agri Food and Biosciences Institute of Northern Ireland
Applied Soil Ecology | Year: 2015

Livestock farming produces slurry, which is normally recycled by land-spreading; but this raises questions about the long-term impact of slurry on soil fauna and soil processes. To examine the long-term effects of slurry on earthworms, cattle and pig excreta slurries and inorganic fertiliser were applied to a ryegrass silage sward for 33 years in a replicated experiment, and earthworms sampled for four consecutive years at three seasonal intervals (March, May and October). Animal slurries were applied at three rates (50, 100 and 200m3ha-1yr-1) and inorganic fertiliser as 200kgN, 32kgP and 160kgKha-1yr-1. Epigeic earthworms, Lumbricus rubellus, Lumbricus juveniles, and the endogeic Allolobophora chlorotica responded strongly and positively to cattle slurry inputs. In the case of L. rubellus, biomass was five times greater in the highest input cattle slurry plots than in the untreated controls. In contrast to Al. chlorotica adults, other endogeic earthworms and juvenile Allolobophora were more associated with the inorganic fertiliser treatment. Aporrectodea juveniles, in particular, had significantly greater biomass in the inorganic fertiliser treatment. However, no such response was demonstrated by adult Aporrectodea caliginosa, the commonest species found, suggesting niche separation between adults and juveniles. Pig slurry applications produced relatively little change in earthworm biomass compared to controls, despite residual copper concentrations; suggesting that organic matter input was counterbalancing the sublethal effects of copper. © 2015 Elsevier B.V.

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