Mercury, arsenic, and cadmium in fish, water, and sediment of American Falls Reservoir, Idaho, 1974.

Mercury and cadmium were found in fish, water, and sediment of American Falls Reservoir (AFR), Idaho. Mercury and cadmium levels in some fish exceeded human health standards set by the Food and Drug Administration, U.S. Department of Health, Education and Welfare, and the World Health Organization. Analyses performed on the flesh of rainbow trout showed mercury residues of up to 1.20 mg/kg, which were higher than residues previously reported in trout collected in 1970 and 1971 from AFR. Cadmium residue levels were as high as 0.80 mg/kg. Although arsenic was found in reservoir sediment at levels of 1.36-2.40 mg/kg, it was not detected in fish.     

Pests,Predators, and Parasites

Abstract

The development of resistance to insecticides and the hazards inherent in their use present ever-increasing problems in insect control today. The difficulties and dangers have given impetus to research on other means of combating pests. Australia has always been prominent in the field of biological control, and the CSIRO Division of Entomology is an important centre, keenly seeking controls for both insects and weeds. Progress in the search for and establishment of parasites of Sirex, the pine pest, was described in Rural Research 64. This article reviews six other projects of particular interest, namely those involving potato moth, buffalo fly, white wax scale, green vegetable bug, lantana, and skeleton-weed.     

Intestinal uptake,metabolism, and transport of naphthol: In vitro capacity,requirements, and inhibition

The metabolism and transport of [¹⁴C]-naphthol were investigated in sacs of rat small intestine to better understand metabolism of the pesticide carbaryl (which contains naphthol) in the intestine. The capacity to synthesize polar ¹⁴C-labeled metabolites was approximately saturated at 50 μM naphthol. The metabolic capacity of the cranial small intestine was about two times the capacity of the caudal. Anaerobic incubation severely suppressed naphthol metabolism. Sodiumfree medium suppressed metabolism only slightly but altered transport of water and of the polar ¹⁴C-labeled metabolites to serosal and mucosal fluids; the effect on metabolite transport cannot be explained by the effects of sodium on water movements, however. Calcium-free medium did not affect metabolism or metabolite transport; 2,4-dinitrophenol, and possibly phlorizin, but not ouabain, suppressed naphthol metabolism in specific regions of the intestine. Each of the three inhibitors altered metabolite transport. It is concluded that the capacity to conjugate naphthol in the small intestine is greater in the cranial than caudal regions; the quantity of naphthol taken up from the medium is proportional to the rate of formation of the polar metabolite, naphthyl glucuronide; addition of 2,4-dinitrophenol, phlorizin, or ouabain, or deletion of sodium, perturbed the transport of the polar metabolite, but the perturbance could not be explained by the effect on rate or direction of fluid transfer and indicated an effect on cellular permeability or on transport mechanisms; the effect of the three inhibitors and possibly of elevated naphthol concentrations (to 520 μM) in the medium on metabolite transport may be by a sodium interaction; the latter suggests that naphthol may be toxic to the intestine at concentrations approaching 100 to 1000 μM.     

Species, Cultivars, Rootstocks and Environment

World apricot production by no means meets the total need of the international market (fresh and processed fruits) and is far below the potential in view of the existing favourable geographic, climatic and agrotechnical conditions. The cause for this insufficient world production of apricots, particularly in certain countries which have favourable conditions for apricot culture and its expansion, should be investigated using scientific and technical concepts concerning the apricot decline syndrome (apoplexy, sudden wilting, withering of apricots). After the mutual assistance of research workers from different disciplines in investigating this complex disease, the economic security of apricot growing can be improved and apricot decline reduced to an acceptable level. Special attention must be paid to selecting appropriate cultivars, rootstocks or interstocks, locations and cultivation techniques.     

Insecticidal activity of N,N-diethyl-, N,N-dipropyl-, N,n-di-isopropyl-, and n,n-di-isobutylalkanamides against mosquito larvae

N,N-Diethyl-, N,N-dipropyl-, N,N-di-isopropyl, and N,N-di-isobutylalkanamides in which the acyl moiety ranged from C₈ to C₂₁ were synthesised, and their larvicidal activity was determined against the first-instar larvae of the southern house mosquito Culex quinquefasciatus Say. The four homologous series of amides generally showed an increase in their larvicidal activity as the carbon number in the acyl moiety of the amides increased, until the activity reached a maximum. Subsequently, an increment of carbon number resulted in declining activity in the higher homologues, until the activity disappeared. N,N-Diethyltetradecanamide, N,N-dipropylundecanamide, N,N-di-isopropylundecanamide, and N,N-di-isobutlynonanamide or -dodecanamide were the most active compounds in their respective homologous series of amides; however, they were less active than their analogous N,N-dimethylalkanamides previously studied.     

Persistence and residual activity of an organophosphate, pirimiphos-methyl, and three IGRs, hexaflumuron, teflubenzuron and pyriproxyfen, against the cowpea weevil, Callosobruchus maculatus (Coleoptera: Bruchidae)

Three insect growth regulators (IGR), the chitin synthesis inhibitors (CSI) teflubenzuron and hexaflumuron and the juvenile hormone mimic (JHM) pyriproxyfen, as well as the organophosphate (OP) pirimiphos-methyl, were evaluated for their activity against the cowpea weevil, Callosobruchus maculatus (F), in cowpea seeds stored for up to 8 months post-treatment. The initial activity data showed that, based on LC50 level, teflubenzuron had strong ovicidal activity (LC50 = 0.056 mg kg(-1)) followed by pirimiphos-methyl (1.82 mg kg(-1)) and pyriproxyfen (91.9 mg kg(-1)). The residual activity data showed that none of the IGRs tested had strong activity when applied at 200 mg kg(-1) in reducing the oviposition rates of C maculatus at various storage intervals up to 8 months post-treatment. However, teflubenzuron reduced adult emergence (F1 progeny), achieving control ranging from 96.2% at 1 month to 94.3% at 8 months. Hexaflumuron showed a similar trend in its residual activity, ranging between 93.8% control at 1 month to 88.2% control at 8 months post-treatment. However, pyriproxyfen was more active than the CSIs tested and caused complete suppression (100% control) of adult emergence at all storage intervals. Unlike the IGRs tested, pirimiphos-methyl applied at 25 mg kg(-1) was more effective in reducing oviposition rates of C maculatus up to 8 months post-treatment. A strong reduction of adult emergence was also observed at various bimonthly intervals (98.6% control at 1 month to 91.6% control at 8 months post-treatment). The persistence of hexaflumuron and pirimiphos-methyl in cowpea seeds was also studied over a period of 8 months. The loss of hexaflumuron residue in treated cowpeas (200 mg kg(-1)) was very slow during the first month post-treatment (4.43%). At the end of 8 months, the residue level had declined significantly to 46.4% of the initial applied rate. The loss of pirimiphos-methyl residue in treated cowpeas (25 mg kg(-1)) was relatively high during the first month post-treatment (36.7%) and increased to 81.6% after 8 months.     

Dieldrin residues in soybeans in Illinois, 1965, 1966, 1967, 1971, and 1974

The Illinois soybean crop was monitored in 1965, 1966, 1967, 1971, and 1974 for dieldrin residues resulting from aldrin applied to corn in the years before soybean cultivation. Residue levels of dieldrin in soybeans increased between 1965 and 1974. The percent of fields which had soybeans with a dieldrin level above 0.03 ppm increased between 1965 and 1974. Dieldrin residue levels in soybeans grown in Illinois are expected to decline now that the use of aldrin has diminished and will soon cease. No significant correlation was evident between the dieldrin levels in soybeans and the area of the State where they had grown, the date of planting, or the variety.     

DDT and BHC residues in some body tissues of goats, buffalo, and chickens, Lucknow, India

Muscle, liver, brain, and abdominal body fat samples of goats, buffalo, and chickens, all common meat sources in India, were analyzed by gas-liquid chromatography (GLC) for residues of DDT and benzene hexachloride (BHC). A few samples of goat and buffalo bone marrow were also included. Relatively high residue levels were found in body fat and bone marrow compared with other tissues. DDT and BHC residue levels were highest in chicken body fat, averaging 4.157 ppm sigma DDT and 3.879 ppm BHC. DDT content was much higher in goat and buffalo bone marrow than in the corresponding body fat. DDT levels in brain samples were highest (0.138 ppm) in buffalo. p,p'-TDE levels were higher than p,p'-DDE levels in buffalo; overall DDT levels were lowest in goats. BHC residues were generally low in buffalo; alpha-BHC accounted for most BHC residues in brain tissues. Greater accumulations of DDT and BHC were found in leg muscles than in breast muscles of chickens.     

四种常用三唑类杀菌剂在香蕉上残留行为及使用评价研究

采用田间试验研究了戊唑醇、氟环唑、苯醚甲环唑、丙环唑等4种常用三唑类杀菌剂在香蕉上的残留行为, 并比较了戊唑醇在套袋与不套袋情况下的最终残留量。研究结果表明：香蕉上戊唑醇、氟环唑、苯醚甲环唑、丙环唑的降解半衰期分别为10.8~14.1、8.1~9.5、7.9~12.9、9.4~15.6 d。在试验剂量条件下, 末次施药后42 d时, 戊唑醇(不套袋)、戊唑醇(套袋)、氟环唑、苯醚甲环唑、丙环唑在蕉肉中的残留量分别为：0.01~0.04、<0.01、0.01~0.08、≤0.01 mg/kg和0.02~0.07 mg/kg; 在全蕉上的残留量分别为0.05~0.47、<0.01、0.10~0.36、0.03~0.19 mg/kg 和0.05~0.32 mg/kg。香蕉果肉占全果的比例约为55%~75 %, 全果的残留量约为果肉2~19倍, 表明香蕉中戊唑醇、氟环唑、苯醚甲环唑、丙环唑主要残存在果皮上。戊唑醇防治香蕉叶斑病, 在套袋情况下可以显著地减少其在收获期香蕉上的残留。     

施肥对小麦、玉米和大豆连作土壤微生物群落功能多样性的影响

为了明确长期施肥和不施肥条件下作物连作对土壤微生物群落功能多样性的影响,以典型黑土为研究对象,选取长期定位实验站长期施肥和不施肥条件下的小麦、玉米和大豆连作处理,通过稀释平板法和Biolog Eco微平板法,测定土壤细菌、真菌、放线菌数量、碳源代谢活性等指标,为建立合理的农田管理措施提供数据支撑和理论依据。结果表明:长期施肥条件下大豆、小麦和玉米连作土壤细菌、真菌和放线菌数量均高于不施肥处理,且均以大豆连作处理细菌和真菌数量最高。不施肥条件下小麦和玉米连作土壤细菌总数较大豆连作处理分别下降了24.8%和31.0%,真菌总数分别下降了64.0%和51.2%;施肥条件下小麦和玉米连作土壤细菌总数则较大豆连作处理分别下降了29.0%和45.5%,真菌总数分别下降了26.7%和31.5%。Biolog结果表明,不施肥条件下小麦连作处理的平均颜色变化率(AWCD)高于玉米和大豆连作处理,施肥条件下则是大豆连作处理的AWCD值高于小麦和玉米连作处理。不施肥条件下大豆、玉米和小麦连作处理利用最多的碳源是碳水化合物类,施肥后不同连作处理利用最多的是碳水化合物类和多聚物类。大豆和小麦连作不施肥条件下土壤微生物利用率最高的碳源均是α-D-乳糖,施肥条件下利用率最高的碳源均是D,L-α-甘油,而不论施肥与否,玉米连作条件下土壤微生物利用率最高的碳源均是D-半乳糖醛酸;葡萄糖-1-磷酸盐和γ-羟基丁酸是农田黑土微生物群落特异利用的关键碳源。主成分分析得出,施肥对土壤微生物碳源代谢能力的影响大于作物的影响。     

啶酰菌胺在南瓜、芦笋、山楂、芒果和木瓜上的膳食摄入风险评估

为明确啶酰菌胺在南瓜、芦笋、山楂、芒果和木瓜上使用可能产生的膳食摄入风险，通过进行规范田间残留试验，检测了南瓜、芦笋、山楂、芒果和木瓜中啶酰菌胺的最终残留量，结合国内和国际两种膳食消费量数据，评估了啶酰菌胺的长期膳食摄入风险，并就两种方法的评估结果进行了比较分析。样品采用QuEChERS方法前处理，液相色谱-串联质谱 (LC-MS/MS) 定量分析。结果表明:南瓜在0.01、0.1和3 mg/kg，芦笋在0.01、0.1和20 mg/kg，山楂在0.01、0.1和60 mg/kg，芒果在0.01、0.1和4 mg/kg，木瓜在0.01、0.1和10 mg/kg添加水平下，啶酰菌胺在空白样品中的平均回收率为79%~101%，相对标准偏差为2%~14%。采用 “中国居民营养与健康状况调查报告” 的膳食消费数据，计算得啶酰菌胺针对普通人群的国家估算每日摄入量 (NEDI) 为0.707 5 mg/(kg bw)，风险商 (RQ) 为28.1%；采用世界卫生组织 (WHO) 提供的每种农产品的单独膳食量进行计算，啶酰菌胺的每日摄入量为0.128 2 mg/(kg bw)，风险商 (RQ) 为5.1%。两种方法的评估结果均表明啶酰菌胺对一般人群的健康不会产生不可接受的风险，然而，采用不同膳食消费数据进行计算会导致风险评估结果存在较大差异，其原因主要是由于中国所采用的膳食消费数据是作物分类基础上的数据，而不是具体某种农产品的单独消费量，因而易导致中国的膳食摄入风险评估结果过于保守。因此建议相关部门进一步完善居民的营养与健康状况调查监测工作，提供具体到每一种农产品的膳食消费数据，以便于科学评价农药对人体健康的风险。     

Population dynamics of Rhizoctonia,Oculimacula, and Microdochium species in soil,roots, and stems of English wheat crops

This study aimed to elucidate the population dynamics of Rhizoctonia, Oculimacula, and Microdochium species, causing the stem base disease complex of sharp eyespot, eyespot, and brown foot rot in cereals. Pathogen DNA in soil, roots, and stem fractions, and disease expression were quantified in 102 English wheat fields in two seasons. Weather data for each site was collected to determine patterns that correlate with assessed diseases. Oculimacula spp. (66%) and R. solani AG 2-1 (63%) were most frequently detected in soil, followed by R. cerealis (54%) and Microdochium spp. (33%). Oculimacula spp. (89%) and R. cerealis (56%) predominated on roots and soil but were not associated with root rot symptoms, suggesting that these species used soil and roots for survival and as inoculum source. M. nivale was more frequently detected than M. majus on stems up to GS 21–30 and co-occurred on plant samples with O. acuformis. O. yallundae had higher DNA concentration than O. acuformis at the lower 5 cm basal region at GS 37–45. R. cerealis predominated in the upper 15 cm above the base beyond stem extension. Brown foot rot by Microdochium spp. was favoured by cool and wet autumns/winters and dominated in English wheat. Eyespot and sharp eyespot disease index by Oculimacula spp. and R. cerealis, respectively, correlated with wet/humid springs and summers. Results suggested that stem base pathogens generally coexisted; however, their abundance in time and space was influenced by favourable weather patterns and host development, with niche differentiation after stem extension.     

Action of some herbicides on growth,respiration, plasmalemma integrity,and proton extrusion of Acer pseudoplatanus cells: II. Amides,diphenyl ethers,nitriles, phenols,triazines, and uracils

The activity of 15 herbicides from different families was assayed on nonphotosynthetic Acer pseudoplatanus cells, in batch suspension culture. They inhibited growth, stimulated the oxygen consumption by cells, and changed the pH evolution of the culture medium. Amides did not seem to disturb the membrane properties. Some diphenyl ethers and phenols directly modified the proton compartmentation of cells whereas some other diphenyl ethers, nitriles, triazines, and uracils altered permeabilities to potassium and leucine. Changes in membrane permeabilities to protons and medium constituents were discussed.     

Contamination, error, and nonspecific molecular tools

ABSTRACT Random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) are widely used in studies of genetic variation. Although it is recognized that contamination should be avoided in DNA samples, little is known about the potential hazards of low level bacterial contamination of samples from which DNA is extracted for RAPD or AFLP analyses. We found that contamination of Aphanomyces cochlioides cultures with a prokaryote at visibly undetectable levels markedly altered the results of RAPD and AFLP analyses. The contamination resulted in seven contaminant-specific RAPD products and in the suppression of eight products characteristic of uncontaminated A. cochlioides cultures. Prokaryote contamination resulted in 39 contaminant-specific AFLP products, but did not cause suppression of AFLP products. Comparing A. cochlioides samples with outgroup A. euteiches did not clearly indicate the presence of contaminant DNA, because uneven product suppression in RAPD analysis increased the apparent similarity between contaminated samples and A. euteiches and because a high proportion of the contaminant-specific amplified products comigrated with products from A. euteiches in both RAPD and AFLP analyses. Work with organisms that are prone to contamination should employ techniques such as restriction fragment length polymorphism or DNA sequence comparisons rather than relying solely on RAPD or AFLP analyses.     

Response of black, cranberry, kidney, and white bean to linuron

Dry bean producers in Ontario, Canada, have few herbicide options available for annual broad-leaved weed management and there is little information on the tolerance of dry bean to linuron. The tolerance of black, cranberry, kidney, and white bean to the pre-emergence (PRE) application of linuron at the rates of 0, 500, 1000, 1500, 2000, and 2500 g ai ha⁻¹ was evaluated in field studies conducted in 2005 and 2006 at Exeter and in 2006 at Ridgetown, Ontario. The four market classes differed in their response to linuron. Cranberry and kidney bean were more tolerant to the PRE application of linuron than black and white bean. Linuron applied PRE caused as much as 12% injury in cranberry and kidney bean, 47% injury in black bean, and 56% injury in white bean. Linuron applied PRE at 500–2500 g ai ha⁻¹ had no effect on the height of cranberry and kidney bean but decreased the height by 7, 8, and 15% in black bean and by 10, 13, and 23% in white bean at 1500, 2000, and 2500 g ai ha⁻¹, respectively. Linuron applied PRE at the rates evaluated did not cause any adverse affect on the yield of cranberry, kidney, and white bean but black bean yield was reduced by 16% at 2500 g ai ha⁻¹. Based on these results, there is not an adequate margin of crop safety for the PRE application of linuron in black and white bean at rates >1000 g ai ha⁻¹. However, there is a potential for the use of linuron PRE for weed management in cranberry and kidney bean at the rates evaluated.     

毒死蜱、吡虫啉、螺虫乙酯及其代谢物和苯醚甲环唑在梨中的残留消解动态

利用仪器分析方法和田间试验法，研究了毒死蜱、吡虫啉、螺虫乙酯及其代谢物和苯醚甲环唑在梨中的残留消解动态。样品经乙腈提取，氯化钠盐析净化，毒死蜱采用气相色谱-质谱联用仪检测，其他3种农药采用液相色谱-质谱联用仪检测，外标法定量。结果表明:毒死蜱、吡虫啉、螺虫乙酯及其代谢物和苯醚甲环唑4种农药在梨中的消解动态均满足一级反应动力学方程，半衰期分别为4.4、12.2、13.1和10.3 d。施药后7 d至收获期，4种农药在梨中的最终残留量均未超出中国国家标准中规定的最大残留限量值，按照推荐剂量及其操作规范在梨上施用是安全的。     

Morphology,phylogeny, and pathogenicity of Trichothecium,Alternaria, and Fusarium species associated with panicle rot on Chenopodium quinoa in Shanxi Province,China

Quinoa panicle rot (QPR) is a novel disease that poses a significant threat to quinoa production in China. Typical symptoms on panicles include a film of pale pink, grey-white, or dark brown mould on the grains during the grain-filling stage. Furthermore, QPR causes quinoa grain discolouration, unfilling, and malformation. In total, 37 isolates were identified as belonging to three species: Trichothecium roseum (nine isolates), Alternaria alternata (12), and Fusarium citri (16) based on morphology, and phylogenetic and pathogenicity characterization. The present study shows for the first time that T. roseum, A. alternata, and F. citri are the pathogens responsible for QPR. An evaluation of the growth and germination rates revealed a significant difference among the three species, with T. roseum and F. citri isolates having higher fitness in warmer (25–30℃) and humid conditions (water activity ≥0.98). However, A. alternata preferred cooler (20–25℃) and more arid conditions, and germinated in a wide range of water activities (water activity of 0.90–1.00). Among the three species, T. roseum and F. citri are probably responsible for the pink and grey diseased grains in humid regions, and A. alternata for the black-brown diseased grains in arid regions. Pathogenicity tests showed that all three species could infect the quinoa panicles. The results of this study provide a basis for the recognition and management of QPR.