Abstract

1 The European spruce bark beetle Ips typographus is a damaging pest on spruce in Europe. Beetle interactions with tree species originating outside the natural range of the beetle are largely unknown and may be unpredictable because trees without a co-evolutionary history with the beetle may lack effective defences. 2 The terpenoid composition and breeding suitability for I. typographus of the historic host Norway spruce Picea abies were compared with two evolutionary naïve spruces of North American origin that are extensively planted in North-West Europe: Sitka spruce Picea sitchensis and Lutz spruce Picea glauca x lutzii. 3 The bark of all three species had a similar chemical composition and similar levels of total constitutive terpenoids, although Norway spruce had higher total induced terpenoid levels. 4 Beetles tunnelling in the three spruce species produced similar amounts of aggregation pheromone. Controlled breeding experiments showed that I. typographus could produce offspring in all three species, with a similar offspring length and weight across species. However, total offspring production was much lower in Sitka and Lutz spruce. 5 Overall, the results of the present study suggest that I. typographus will be able to colonize Sitka and Lutz spruce in European plantations and in native spruce forests in North America if introduced there.

Abstract

Volatiles emitted by plants convey an array of information through different trophic levels. Animals such as host-seeking herbivores encounter plumes with filaments from both host and non-host plants. While studies showed a behavioral effect of non-host plants on herbivore host location, less information is available on how a searching insect herbivore perceives and flies upwind to a host-plant odor plume within a background of non-host volatiles. We hypothesized here that herbivorous insects in search of a host-plant can discriminate plumes of host and non-host plants and that the taxonomic relatedness of the non-host have an effect on finding the host. We also predicted that the ratio between certain plant volatiles is cognized as host-plant recognition cue by a receiver herbivorous insect. To verify these hypotheses we measured the wind tunnel response of the moth Argyresthia conjugella to the host plant rowan, to non-host plants taxonomically related (Rosaceae, apple and pear) or unrelated to the host (Pinaceae, spruce) and to binary combination of host and non-host plants. Volatiles were collected from all plant combinations and delivered to the test insect via an ultrasonic sprayer as an artificial plume. While the response to the rowan as a plant was not affected by the addition of any of the non-host plants, the attraction to the corresponding sprayed headspace decreased when pear or apple but not spruce were added to rowan. A similar result was measured toward the odor exiting a jar where freshly cut plant material of apple or pear or spruce was intermixed with rowan. Dose-response gas-chromatography coupled to electroantennography revealed the presence of seven field attractive and seven background non-attractive antennally active compounds. Although the abundance of field attractive and of some background volatiles decreased in all dual combinations in comparison with rowan alone, an increased amount of the background compounds (3E)-4,8-Dimethyl-1,3,7-nonatriene ((E)-DMNT) and (Z)-3-hexenyl acetate was found in the rowan-apple and rowan-pear but not in the rowan-spruce headspace. A higher ratio between the abundance of each field attractive component and that of (E)-DMNT and (Z)-3-hexenyl acetate was measured for rowan and rowan-spruce in contrast to rowan-pear and rowan-apple headspaces. Our result suggests that the ratio between field attractive and background antennaly active volatiles encodes host-plant recognition in our study system.

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Abstract

Sewage sludge is an important amendment that enriches soils with organic matter and provides plants with nutrients such asnitrogenandphosphorus.However,knowledgeonthe fateandeffectsof organic pollutants presentin the sludge on soilorganisms is limited.In the present study, the uptake of triclosan, galaxolide, and tonalide in the earthworm Dendrobaena veneta was measured 1 wk afteramendment of agricultural soil with sewage sludge, while elimination kinetics were assessed over a 21-d period after transferring worms toclean soil. After 1-wk exposure, earthworms had accumulated 2.6  0.6 mgg1galaxolide, 0.04  0.02 mgg1tonalide, and0.6  0.2 mgg1triclosan. Both synthetic musks were efficiently excreted and below the limit of quantification after 3 and 14 d ofdepuration for tonalide and galaxolide, respectively. Triclosan concentrations, on the other hand, did not decrease significantly over thedepuration period, which may lead to the transfer of triclosan in the food web.

Abstract

Nonylphenols (NP) are a group of alkylphenols, formed upon degradation of nonylphenol ethoxylates such as nonylphenol monoethoxylate (NP1EO) or nonylphenol diethoxylate (NP2EO), which have been broadly used as non-ionic surfactants. Both NP and their ethoxylates are often present in the sewage, despite being banned and substituted by less toxic alcohol ethoxylates in many countries. There is a number of degradation studies of nonylphenol in the soil environment, but there is a lack of understanding on how plants and soil organisms such as earthworms can affect the degradation. In our study, we investigated the degradation of 4-nonylphenol (4-NP) in a mineral field soil in the presence of barley (Hordeum vulgare) and earthworms (Aporrectodea caliginosa). Soil was spiked with 4-NP at a concentration of 12.5 mg kg-1 d.w. soil. Results showed that the degradation of 4-NP in soil was rapid during the 28 days after spiking, with remaining concentration of 0.397 mg kg-1 d.w. soil on day 28. Degradation was much slower between days 28 and 120, with a remaining concentration of 0.214 mg kg-1 d.w. soil on day 120. No significant difference in the degradation of 4-NP in the presence of either plants or worms was observed, but sampling after 28 days of exposure revealed transfer of 4-NP to worms (worm tissue concentration = 0.79 μg g-1), which increased with time (1.66 μg g-1 after 120 d). The calculated transfer factor after 28 (TF28) and 120 days (TF120) was 0.07 and 0.13 respectively. No toxicity or accumulation in plants was observed at the concentration tested herein. Concentration of 4-NP in the rhizosphere was not statistically different from that in the bulk soil.

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Abstract

This project evaluated whether the principles of combined toxicity assessment (CTA) and cumulative risk assessment (CRA) can be used to predict the toxicity of ecologically-relevant mixtures of plant protection products (PPPs) in surface waters receiving run-off from Norwegian agricultural areas. A combination of testing solid phase extracts (SPE), whole surface water and a synthetic mixture in an algal bioassay and predicting combined toxicity using CTA models were conducted on selected samples from the Heia catchment (Råde, Norway). The results demonstrated that designing and testing synthetic mixtures on the basis of measured concentrations of PPPs was the best method for the accurate determination of combined toxicity due to confounding factors introduced by whole water and SPE testing. Combined toxicity models based on Concentration Addition (CA) successfully predicted the toxicity of the complex synthetic mixture and verified that a mixture of PPPs acted in an additive manner. Tiered assessment of the cumulative risk of active PPP substances and PPP formulations proposed by the European Food Safety Authority (EFSA) were considered applicable also for the CRA of complex environmental mixtures and could potentially aid the identification of relevant mixtures, risk drivers and susceptible species as input to the assessment and approval of PPPs.

Abstract

This paper investigated the possibility of leaving out the traditional clean-up step in the QuEChERS procedure and analysing non-cleaned extracts from fruit, vegetables and cereals with a combination of gas chromatography-tandem mass spectrometry (GC-MS/MS), back-flush technology and large-volume injection. By using calibration standards in cucumber matrix, recovery and precision were calculated in lettuce, orange and wheat for 109 pesticides at 0.01 and 0.1 mg kg−1 in two sets of samples: one with and one without clean-up. For both spiking levels, 80–82% of the pesticides in the non-cleaned extracts and 80–84% of the pesticides in the cleaned extracts were within the acceptable recovery range of 70–120%. Precision data for both levels showed that 95% of the pesticides in the non-cleaned extracts and 93–95% of the pesticides in the cleaned extracts had RSDs below 20%. Recovery and precision data were determined using a two tailed t-test (p = 0.05). By using calibration standards in the respective matrix, we studied if the non-cleaned calibration standards gave an extra matrix effect compared with the cleaned standards by using the slope from calibration graphs and plotting the calculated extra matrix effect minus 100 for each compound. The results showed that for 79% of the pesticides, the extra matrix effect minus 100 was within the acceptable range of −20% to 20%. Five European Union proficiency tests on rye, mandarin, rice, pear and barley, respectively, from 2010 to 2012 were reanalysed omitting the clean-up step and showed satisfactory results. At least 70 injections of non-cleaned extracts were made without detecting any increased need for maintenance during the experimental period. Analysing non-cleaned QuEChERS extracts of lettuce, orange and wheat are possible under the conditions described in this paper because recovery, precision and specificity showed satisfactory results compared with samples subjected to traditional dispersive clean-up.

Abstract

The gas chromatography mass spectrometry (GC-MS) deconvolution reporting software (DRS) from Agilent Technologies has been evaluated for its ability as a screening tool to detect a large number ofpesticides in incurred and fortified samples extracted with acetone/dichloromethane/light petroleum(Mini-Luke method). The detection of pesticides is based on fixed retention times using retention timelocking (RTL) and full scan mass spectral comparison with a partly customer built automated massspectral deconvolution and identification system (AMDIS) database. The GC-MS was equipped with a programmable temperature vaporising (PTV) injector system which enables more sample to be injected.In a blind study of 52 real samples a total number of 158 incurred pesticides were found. In addition to the 85 pesticides found by manual interpretation of GC-NPD/ECD chromatograms, the DRS revealed 73 morepesticides (+46%). The DRS system also shows its potential to discover pesticides which are normally notsearched for (EPN in long beans from Thailand). A spiking experiment was performed to blank matricesof apple, orange and lettuce with 177 different pesticides at concentration levels 0.02 and 0.1 mg/kg. The samples were analysed on GC-MS full scan and the AMDIS match factor was used as a mass spectralquality criterion. The threshold level of the AMDIS match factor was set at 20 to eliminate most of thefalse positives. AMDIS match factors from 20 up to 69 are regarded only as indication of a positive hit andmust be followed by manual interpretation. Pesticides giving AMDIS match factors at ≥70 are regarded as identified. To simplify and decrease the large amount of data generated at each concentration level,the AMDIS match factors ≥20 was averaged (mean AMF) for each pesticide including the commodities and their replicates. Among 177 different pesticides spiked at 0.02 and 0.1 mg/kg level, the percentage of mean AMF values ≥70 were 23% and 80%, respectively. For 531 individual detections of pesticides (177pesticides×3 replicates) giving AMDIS match factor 20 in apple, orange and lettuce, the detection rates at 0.02 mg/kg were 71%, 63% and 72%, respectively. For the 0.1 mg/kg level the detection rates were 89%,85% and 89%, respectively. In real samples some manual interpretation must be performed in addition. However, screening by GC-MS/DRS is about 5-10 times faster compared to screening with GC-NPD/ECDbecause the time used for manual interpretation is much shorter and there is no need for re-injection on GC-MS for the identification of suspect peaks found on GC-NPD/ECD.