Have emission reductions led to improvements in water quality at Loch Dee in Galloway?

A comprehensive study began in 1980, at the Loch Dee catchment (south west Scotland), to study the effects of acidification and coniferous afforestation on streamwater ecology. When the project started, acid emissions were high but have since declined and stabilised. Average rainfall pH did not change significantly during the study period but total sulphate concentrations declined by 30%. The Loch Dee basin has three main subcatchments. Almost 70% of the Green Burn subcatchment was planted with Sitka spruce, between 1973 and 1975 and canopy closure has occurred at lower altitudes. Comparison of the water chemistry of the Green Burn and the Dargall Lane was done with cusum plots. The pH in the Green Burn has fallen relative to the Dargall Lane, whereas total and non-marine sulphate concentrations have remained unchanged over the last 10 years.     

安徽省合肥市家禽高致病性禽流感血清学调查

2017年秋,我国开始采用高致病性禽流感(H5+H7)二价灭活疫苗,对家禽实行强制免疫。为评价该疫苗在合肥市家禽中的免疫效果,科学制定该地区免疫计划和防控措施,2017年10月—2018年10月,在春季和秋季集中强制免疫后,分别随机抽取养殖场、交易市场和自然村散养户家禽血清样品,进行3次集中抗体监测;在2018年春季集中免疫前和免疫后,选取22个固定家禽养殖场,开展定点抗体监测。集中监测结果显示:高致病性禽流感抗体场点合格率从2017年秋季的48.0%,分别提高到2018年春季的96.6%和秋季的95.5%,2018年的H5、H7亚型个体合格率均高于2017年秋季水平,差异均有统计学意义(P<0.01)。定点监测结果显示:免疫后21d,H5亚型禽流感抗体个体合格率由92.6%降到58.2%,但60d后又大幅回升到90.8%,差异极显著(P<0.01);而H7亚型抗体合格率却直线上升,个体合格率差异有统计学意义(P<0.01)。上述结果表明,高致病性禽流感(H5+H7)二价灭活疫苗防护效果较好,可显著提升H5和H7亚型抗体场点合格率和个体合格率,使其达到免疫保护水平,因此应继续加强该疫苗的免疫、监测,根据实际情况及时补免。     

Monitoring of Bark and Wood-Boring Beetles in France after the December 1999 Storms

After the December 1999 storms, two networks were set up over 2 years (2000 and 2001) to assess the scale and type of insect colonisation on storm damaged trees and to interpret these events for the future. The Level 1 network, was a large-scale survey that covered the entire storm area and provided qualitative observations on its 898 plots in which every major tree species was assessed. The Level 2 network, was a regional survey set up only in two regions: the 'Landes' region and the Northeast of France. The observations were intensive and quantitative, devoted only to maritime pine in the 'Landes' region and to Norway spruce in the Northeast of France. The Level 1 network indicated that less than 40% of the storm damaged trees were colonised by bark beetles in September 2000. No attacks were observed on standing trees in 2000 but many occurred during 2001 in spruce and maritime pine stands. The Level 2 network in the Vosges mountains showed a late colonisation in October and November 2000. The emerging population of Ips typographus on attacked trees reached 25 000–30 000 insects/m³. This huge population combined with the low rate of parasitism in 2001 leads to the expectation of increasing damage in spruce stands next year.     

A Monitoring System for Green Fluorescence Protein Gene-transformed Fusarium oxysporum in Melon Seedlings

Using melon seedlings at the cotyledon stage and genetically marked fungi, a system for monitoring pathogenic and nonpathogenic Fusarium oxysporum was devised in the present study. Protoplasts were prepared from three formae speciales (melonis, radicis-lycopersici and fragariae )of F. oxysporum and transformed with a synthetic gene for green fluorescence protein. Transformants were primarily isolated in the presence of hygromycin B and then screened by the emission of bright green fluorescence. Roots of melon seedlings were inoculated with fluorescing microconidia of these fungi, and fungal infection behavior was traced. Using fluorescence microscopy, we directly observed not only the fungus at the root surface, but also the mycelia elongating in the trachea of roots. Both pathogenic and nonpathogenic fungi germinated and hyphae elongated superficially on the surface of root. Only pathogenic fungi caused root necrosis at the inoculation site. Hyphae grew within the stem to induce constriction or cracking of lower hypocotyls, then causing wilting of the seedlings. Infection behavior of genetically marked pathogenic and nonpathogenic F. oxysporum could be successfully monitored after inoculation of cotyledons of seedlings. Received 6 June 2001/ Accepted in revised form 3 August 2001     

Relationships between watershed Stressors and sediment contamination in Chesapeake Bay estuaries

Three methods for assessing the relationships between estuarine sediment contaminant levels and watershed Stressors for 25 Chesapeake Bay sub-estuaries were compared. A geographic information system (GIS) was used to delineate watersheds for each sub-estuary and analyze land use pattern (area and location of developed, herbaceous and forested land) and point source pollution (annual outflow and contaminant loading) using three landscape analysis methods: (1) a watershed approach using the watershed of the estuary containing the sampling station. (2) a partial watershed approach using the area of the watershed within a 10 km radius of the sampling station and (3) a weighted partial watershed approach where Stressors within the partial watershed were weighted by the inverse of their linear distance from the sampling station. Nine sediment metals, 16 sediment organics and seven metals loading variables were each reduced to one principal component for statistical analyses. Relationships between the first principal components for sediment metals and organics concentrations and watershed stressor variables were analyzed using rank correlation and stepwise multiple regression techniques. For both metals and organics, the watershed method yieldedR ² values considerably lower than the partial and weighted partial watershed analysis methods. Regression models using Stressor data generated by the weighted partial watershed landscape analysis method explained 76% and 47% of the variation in the first principal component for sediment metals and organics concentrations, respectively. Results suggest that the area of developed land located in the watershed within 10 km of the sediment sampling station is a major contributing factor in the sediment concentrations of both metals and organics.     

安徽庐江褐飞虱的抗药性监测及不同杀虫剂对其田间防效评价

近年来,褐飞虱田间种群已对多种药剂产生了抗性,为筛选可防控褐飞虱的高效药剂,2020年-2022年采用稻茎浸渍法连续测定了安徽省庐江县褐飞虱种群对三氟苯嘧啶、呋虫胺、烯啶虫胺、吡蚜酮、氟啶虫胺腈等5种药剂的抗性水平,并在庐江县开展了不同药剂对褐飞虱田间防效试验。室内抗性监测结果表明,2020年-2022年褐飞虱种群对吡蚜酮始终处于高水平抗性(抗性倍数104.6~154.4倍),对呋虫胺的抗性从中等水平上升至高水平(抗性倍数77.7~157.2倍),对氟啶虫胺腈、烯啶虫胺处于中等水平抗性(氟啶虫胺腈抗性倍数21.3~64.5倍、烯啶虫胺抗性倍数14.6~22.6倍),对三氟苯嘧啶处于敏感状态。庐江单季稻试验田田间试验结果表明,在推荐高剂量下,20%三氟苯嘧啶WG、10%异唑虫嘧啶SC等介离子杀虫剂对褐飞虱速效性和持效性表现较好,除了药后1 d 20%三氟苯嘧啶WG防效为74.72%外,2种药剂3~14 d的防效都在80%以上;50%烯啶虫胺SG、22%氟啶虫胺腈SC防效次之,药后1 d防效在67.63%~71.61%,药后3 d至7 d防效有所提高,为77.16%~84.13%,而药后14 d防效降为71.52%~75.77%;50%吡蚜酮WG药后1~7 d防效均在约70%,而药后14 d下降为62.12%;20%氟啶虫酰胺SC、20%呋虫胺WG、10%醚菊酯SC速效性和持效性都表现较差,药后1~14 d防治效果都在80%以下。结合室内抗药性监测和田间防治效果,说明三氟苯嘧啶等介离子类杀虫药剂作为新型杀虫剂品种,可与新烟碱类、吡蚜酮及其混剂交替轮换使用,用于抗药性褐飞虱的治理。