几种农田作物害鼠经济阈值的测定

1 引言 农田害鼠的危害经济阈值是害鼠防治的依据,也是害鼠管理的一个重要指标,王华弟等及邢林等曾报道过这方面的研究,但未能考虑害鼠群落中各种鼠的数量组成比例和危害强度的不同,1983年,在山东     

Transitional sublethal and lethal effects of insecticides after dermal exposures to five economic species of wireworms (Coleoptera: Elateridae)

During an insecticide toxicity study involving field-collected dusky wireworm, Agriotes obscurus (L.) (Coleoptera: Elateridae), wireworms exposed dermally to six classes of insecticides exhibited characteristic transitional symptoms of toxicity. These symptoms, collectively termed "morbidity," were categorized as "writhing," "leg and mouthpart movements," or "mouthpart-only body movements." These symptoms could persist for long periods, depending on insecticide and dose, with morbid wireworms ultimately recovering or dying. Additional LC50 and LD50 toxicity studies showed that these stages of morbidity also occurred in four other wireworm species, notably Agriotes sputator (L.), Limonius canus LeConte, Ctenicera pruinina (Horn), and Ctenicera destructor (Brown). In addition, all species exposed dermally to clothianidin moved in significant numbers to the surface of soil in posttreatment holding cups. This movement was not observed when these species were exposed to chlorpyrifos or the control solvent. These findings suggest that toxicity trials involving wireworms should include observations on morbidity, and the duration of trials should continue until symptoms of morbidity cease. The long-term morbidity and potential recovery or death of wireworms exposed to certain insecticides has implications for how laboratory and field studies can be better designed and interpreted in the future.     

The biology and management of wireworms (Agriotes spp.) on potato with particular reference to the U.K.

1 This paper reviews and interprets relevant work on the biology and management of wireworms (Agriotes spp.) within the context of potato production in Europe, with particular reference to the U.K. Although the review concentrates on Agriotes spp., the extensive world literature on other Elateridae of economic importance is also drawn upon. 2 Possible reasons for the apparent increase in the importance of wireworms on the potato crop are discussed, followed by a review of wireworm biology, risk assessment techniques (soil sampling, bait trapping and adult pheromone trapping), crop damage, and cultural, biological and chemical control methods. 3 It is clear that the process of site risk assessment followed by appropriate control measures (usually insecticide use) will remain the mainstay of wireworm management programmes. However, there is considerable scope for adopting new risk assessment techniques, such as pheromone trapping of adult beetles. 4 These control measures will need to be underpinned by a greater understanding of wireworm biology, particularly adult dispersal. Factors affecting the initiation and maintenance of wireworm populations in individual fields also require further study. The current use of insecticides could also be optimized by a better appreciation of the interactions between insecticide use, potato variety choice and harvest dates.     

Food habits of pasture wireworm,Conoderus exsul (Coleoptera: Elateridae)

Abstract

The food preferences and rates of growth of the omnivorous pasture wireworm, Conoderus exsul (Sharp) were studied. Larvae of soil-living insects were preferred to germinating maize seed, and wireworm growth rate was greater on insect compared with plant food. In glasshouse pot trials, wireworms increased their attack rate as the density of grass grub (Costelytra zealandica (White)) or white-fringed weevil (Graphthognathus leucoloma Boheman) larvae was increased. In field experiments that compared grass grub numbers in cages accessible to wireworms or protected from predators, predation varied with season from a low of 15% in late summer up to 82% in late autumn. White-fringed weevil larval mortality was increased by addition of wireworms in two field experiments, but not affected in a third trial where initial white-fringed weevil density was low. Grass grub mortality was increased by the presence of wireworms in field plots. Adult C. exsul were observed feeding on sweetcorn pollen.     

Wireworm (Coleoptera: Elateridae) identity, monitoring and damage in sugarcane

Abstract Wireworms (Coleoptera: Elateridae) damage the eyes and young shoots of germinating cane setts in many growing regions. Insecticides can be applied at planting to avoid damage. However, there are no guidelines for deciding on whether treatment is warranted and a sampling method to detect wireworms before planting has not been developed. Baits of rolled oats were tested as a method for detecting wireworms in preplant fallows. In 1995 at Bundaberg, the reduction in crop establishment when treatment was withheld was positively correlated with the catch of wireworms at baits before planting. However, no similar relationship was seen in 1996 or at Mackay in either 1995 or 1996: severe damage was recorded on one farm at Mackay where no wireworms had been found. A sampling plan was developed to estimate wireworm numbers at baits with a fixed level of precision. Wireworms collected at the baits and in samples from established canefields in Queensland and New South Wales included five named and 21 unnamed species from five genera, the most abundant being Agrypnus , Conoderus and Heteroderes . Possible barriers to the adoption of baiting as a decision-support tool are discussed. Development of a reliable monitoring system would require considerably more research, which could not be justified at present.     

Preventive application of an entomopathogenic fungus in cover crops for wireworm control

Efficacy of the Metarhizium brunneum Petch (Hypocreales: Clavicipitaceae) strain ART2825 for control of wireworms (Agriotes obscurus (L.), Coleoptera: Elateridae) was examined in a semi-field pot experiment. Pots were treated in late summer during sowing of spring oat as a cover crop. Survival of wireworms was assessed four weeks after their release in October 2013, and 30 weeks after release in April 2014. Viability and persistence of the fungus was determined by counting colony forming units from substrate samples and microsatellite analyses of recovered Metarhizium isolates. The number of colonies detected in the substrate in October 2013 increased with increasing concentrations of applied conidia, and no significant reduction was observed at the second evaluation date in April 2014. Increasing conidia application rates significantly increased mycosis and reduced wireworm survival, to a level comparable to that of treatment using insecticide-coated oat seeds. The preventive application of M. brunneum conidia to reduce wireworm populations in cover crops, preceding a damage-sensitive crop like potatoes, may be a promising biocontrol strategy.     

经遗传修饰生物体的研究进展及其释放后对环境的影响

８０年代以来,以基因工程为代表的生物技术突飞猛进。转移不同性状的转基因作物在美国被批准进入大田试验的有４０个以上的作物,包括小麦、玉米和水稻等４种谷类粮食作物,主要的纤维作物棉花,蔬菜种类１０种以上,水果９种,其它还有油料作物,牧草和花卉等。到１９９６年６月已被批准进入市场的已有１８种,还有一批有待批准商业化。今年２月,美国农业部已第一次批准一种喂饲其它螨的转基因螨进入大田试验。第一个转基因线虫也正在申请向环境释放。已至少有２５个发展中国家,１０个以上作物转基因成功,ＧＭＯｓ作大田释放的总数在１６０次以上。基因工程能带来巨大的经济效益和社会效益。但是有不少数量的科学家或如“有关科学家联盟”等一些非政府组织指出基因工程的产物向环境释放会可能带来生态或环境危险。发达国家中,美国与欧洲国家的政府对ＧＭＯｓ批准释放的态度也是一样的,后者要比前者慎重得多。最近丹麦科学家已证实转基因油菜中的抗除草剂基因已经转入杂草中;由美国一种子公司开发的转基因大豆被证实对人体过敏而其产品决定不向市场投放。要有充分的科学实验,自然科学家与社会科学家相结合,对经遗传修饰生物体可能带来巨大经济效益和造成环境或生态危机进行充分的评估。在这基础上作出权衡,供政府决策者能作出正确的决策。这不仅在中国而是在全世界范围内已到了一个关键时刻。因此,生物安全问题是每次《生物多样性公约》缔约国会议的主要讨论议题。     

Effects of crop rotation and fertilization on catalase activity in a soil of the southeastern United States

Summary Catalase activity of a loamy sand under a 3-year crop rotation in the southeastern U.S.A. was monitored. Corn (Zea mays L.), cotton (Gossypium hirsutum L.), and soybean [Glycine max (L.) Merr.] were the summer crops in the rotation. Winter wheat (Triticum aestivum L.) was planted after corn, and soybean was followed by a winter fallow period. Cotton was followed by a mixture of common vetch (Vicia sativa L.) and crimson clover (Trifolium incarnatum Gibelli & Belli) which was eventually plow-incorporated as a green manure. Highest mean catalase activities were recorded in soil under the wheat, soybean, and winter legume crops; lowest activities were found in soil bearing corn and cotton, and during the winter fallow period. The fertilization regime influenced soil catalase activity independently of the crop. Soil deficient in any of the major elements showed low enzyme activity. Highest activity was found in soil fertilized with P and K, and with N supplied by a winter legume crop. Addition of supplementary mineral nitrogen to this regime reduced catalase activity. Elimination of the winter legume crop from an otherwise complete fertilization regime resulted in a drastic reduction in enzyme activity. In soil receiving a complete fertilization regime there was a close correlation between soil catalase and xylanase activities. A similar correlation between these two enzymes was not found in soil receiving incomplete fertilization.     

The porous-membrane technique for root studies of field-grown crops

A porous-membrane technique has been successfully used in root studies of field-grown soybean,Glycine max L. Merr., for several years. In order to evaluate this technique on other crops, a study was conducted to compare growth parameters of individual soybean, cotton,Gossypium hirsutum L., and corn,Zea mays L., plants grown with and without their root systems confined within porous membranes. Results indicate that plant species respond differently to root confinement.Root confinement reduced all shoot growth and yield parameters of the crop species, however the reduction was generally greatest for cotton. Apparently, cotton is less adaptable to the restricted rooting volume. Root confinement reduced levels of potassium and phosphorus in soybean and nitrogen in corn and cotton. Fertilizer rates higher than soil test recommendations should be applied to membrane-grown plants to prevent reductions in nutrient levels. It may be possible that modifying the size or shape of the membrane may enhance root and shoot growth of specific crop plants like cotton and increase the ability of this technique to be used on a broader spectrum of crop plants.     

Survey of indigenous bacterial endophytes from cotton and sweet corn

The genotypic diversity of indigenous bacterial endophytes within stems and roots of sweet corn (Zea mays L.) and cotton (Gossypium hirsutum L.) was determined in field trials throughout one growing season. Strains were isolated from surface-disinfested tissues and identified by fatty acid analysis. Gram-negative bacteria comprised 70.5% of the endophytic bacteria and 27 of the 36 genera identified. The most frequently isolated groups from sweet corn roots, were Burkholderia pickettii and Enterobacter spp.; from sweet corn stems, Bacillus megaterium. Bacterial genera present in sweet corn roots were also generally present in sweet corn stems. However, Burkholderia gladioli, Burkholderia solanacearum and Enterobacter cloacae were isolated much more frequently from sweet corn roots than stems, whereas Methylobacterium spp. were found more frequently in sweet corn stems than roots. Agrobacterium radiobacter, Serratia spp. and Burkholderia solanacearum, were the most frequently isolated groups from cotton roots; and Bacillus megaterium and Bacillus pumilus from cotton stems. Acinetobacter baumannii and Arthrobacter spp. were present in cotton stems but not in cotton roots. There were 14 taxonomic groups present in cotton roots that were not in cotton stems; all but one were Gram-negative. These included, Agrobacterium radiobacter, Bacillus megaterium, Bacillus pumilus, Enterobacter asburiae, Pseudomonas chlororaphis, Serratia spp. and Staphylococcus spp. Rhizobium japonicum and Variovorax paradoxus were isolated, almost exclusively, from the roots of both crops. Bacterial taxa present in both sweet corn and cotton early in the season were generally present late in the season. The diversity of bacteria was greater in roots than stems for each crop.     

Wireworm populations in relation to crop production: I. A large-scale flotation method for extracting wireworms from soil samples and results from a survey of 600 fields

The wireworm survey in the Eastern Counties revealed many cases where the observed wireworm damage failed to correspond with the estimated field population. A possible explanation for this was the inaccuracy of counts made by picking wireworms out of the soil samples by hand. Tests showed that such methods recovered an extremely variable proportion of the wireworms in the- samples and, on the average, only two-fifths of the larvae were obtained. A modified form of the washing and flotation technique used by Salt & Hollick (1944) was introduced for large-scale work and is described. By this method, ten samples of soil (4 in. diam. and 6 in. deep) bulked together are examined at a time and can be dealt with at the rate of 13 samples per man per hour with an efficiency of 95-100% in the extraction of wireworms. The populations estimated on 600 fields sampled between December 1942 and May 1943 have thrown more light on the size and composition of the wireworm population in grass and arable fields. Inspection of the crop results on fields tested by the washing process showed a much closer relationship between wireworm population and wireworm damage than had been obtained by the hand-sorting method in the previous year.     

Guilty by association: an evaluation of millipedes as pests of carrot and sweet potato

An evaluation of the pest potential of millipede species occurring in Ontario sweet potato and carrot fields was conducted in response to recent grower concerns about the presence of millipedes in close proximity to damaged vegetables. This study is the first North American survey of millipedes on arable soils and the first evaluation of North American millipede damage to sweet potatoes and carrots. Through field surveys, Cylindroiulus caeruleocinctus was found to be the dominant millipede species in Ontario sweet potatoes and carrots. Fields were surveyed over the growing season, and the factors important to each species’ abundance were evaluated using Minimum AIC Estimation (MAICE). Post‐harvest damage assessments were performed, and MAICE analysis was used to determine which arthropod and environmental parameters were most important in explaining damage to sweet potatoes and carrots. Wireworm (Elateridae) abundance was consistently found to explain root damage better than C. caeruleocinctus abundance, and it is concluded that the majority of field‐observed damage was caused by wireworms. C. caeruleocinctus was negatively correlated with both wireworms and damage in carrot fields and is not likely to be a pest of that vegetable. However, abundance of C. caeruleocinctus in sweet potatoes was positively correlated with both wireworms and damage. This species may cause some damage to sweet potato tubers under field conditions, but management tactics should focus on wireworms as the primary source of damage.     

Overwintering of Heliothis virescens (F.) and Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) in cotton fields of northeast Mississippi

Following the 1995-2001 crop seasons, population densities of pupae of tobacco budworm, Heliothis virescens (F.), and corn earworm, Helicoverpa zea (Boddie), overwintering in cotton fields, Gossypium hirsutum L., in Monroe County, MS, were estimated by digging a total of 43,542 m-row. Densities of pupae varied greatly among years with the highest densities occurring in years with low rainfall in the late summer and early fall. The sex ratio of pupae was variable and significantly male-biased in some years. The total area-wide, tobacco budworm population emerging from all overwintering sites was estimated from catches in pheromone traps whose absolute efficiency is known. After the introduction of Bacillus thuringiensis Berliner (Bt)-transgenic cotton in 1996 but before a several-fold increase in use of herbicide resistant (HR)-transgenic cotton cultivars in 2001, local cotton fields accounted for <2% of the total overwintered tobacco budworm population. In the pretransgenic cotton production era, it is estimated cotton fields typically accounted for <10% of the overwintered tobacco budworm population. Driving surveys of the tillage status of cotton fields and pheromone trapping to determine the timing of adult emergence in the spring indicate that--until the 2000 crop season--postseason tillage destroyed most tobacco budworm and corn earworm pupae overwintering in cotton fields. Adoption of HR-transgenic cultivars has quintupled cotton field area planted no-till, but the contribution of cotton fields to overwintered tobacco budworm populations has remained low. Preemptive tillage of cotton fields to kill overwintering tobacco budworm pupae would not appreciably suppress in-season population densities of this pest. However, the absence of such tillage might increase the rate at which the tobacco budworm develops resistance to insecticides and counteradaptation to antibiotic host plant resistance traits including the Bt-transgenic trait.     

Influence of Selected Plant Species on Hatching of Eggs and Development of Juveniles of Heterodera glycines

The influence of selected plant species on egg hatch and subsequent development of Heterodera glycines race 3 was investigated. Plants tested included four soybean cultivars, red clover, alfalfa, hairy vetch, field corn, sweet corn, cabbage, tobacco, cotton, and wheat. Soybean stimulated egg hatching more than any of the other plant species, with H. glycines-resistant cultivars being more stimulating than susceptible ones. Hairy vetch also increased hatch. Roots of cabbage, red clover, alfalfa, and hairy vetch were readily penetrated by juveniles of H. glycines. Maturation to adult occurred only on soybean and hairy vetch.     

丛枝菌根真菌对植物根尖分生区和根冠细胞的侵染*

一般说来,从枝菌根（ＡＭ）真菌大多数是从植物根系根毛区（成熟区）侵入和扩展的,在显微镜下往往看不到根尖分生区和根冠表皮细胞被ＡＭ真菌侵染的特征。这就很容易给人们造成一种假象,似乎ＡＭ真菌不能侵染根尖分生区和根冠表皮细胞,即它们对ＡＭ真菌是免疫的。然而笔者多次于显微镜下看到ＡＭ真菌侵染根尖分生区和根冠表皮细胞,并形成典型的泡囊、丛枝、菌丝等结构。这一现象导致作者在温室盆栽和大田条件下研究了玫瑰红巨孢囊霉（ Ｇｉｇａｓｐｏｒａ　ｒｏｓｅａ Ｎｉｃｏｌ　＆ Ｓｃｈｅｎｃｋ）、珠状巨孢囊霉（Ｇｉｇａｓｐｏｒａ　ｍａｒｇａｒｉｔａ　Ｂｅｃｋｅｒ　＆　Ｈａｌｌ）、根内球囊霉（Ｇｌｏｍｕｓ　ｏｍｔｒａｒａｄｉｃｅｓ　ｓｃｈｅｎｃｋ　＆　Ｓｍｉｔｈ、摩西球囊霉（Ｇｌｏｍｕｓ ｍｏｓｓｅａｅ （Ｎｉｃｏｌ　＆ Ｇｅｒｄ．） Ｇｅｒｄｅｍａｎｎ　＆ Ｔｒａｐｐｅ）、地表球囊霉（ Ｇｌｏｍｕｓ ｖｅｒｓｉｆｏｒｍｅ（ Ｋａｒｓｔｅｎ）Ｂｅｒｃｈ）和弯丝硬囊霉（ Ｓｃｌｅｒｏｃｙｓｔｉｓ　ｓｉｎｕｏｓａ　Ｇｅｒｄｅｍａｎｎ　＆ Ｂａｋｈｉ）对棉花（Ｇｏｓｓｙｐｉｕｍ　ｈｉｒｓｕｔｕｍ　Ｌ．）、烟草（Ｎｉｃｏｔｉａｎａ　 ｔａｂａｃｕｍ Ｌ．）和白     

Influence of corn on stink bugs (Heteroptera: Pentatomidae) in subsequent crops

In southeastern United States farmscapes, corn, Zea mays L., is often closely associated with peanut, (Arachis hypogaea L.), cotton, (Gossypium hirsutum L.), or both. The objective of this 3-yr on-farm study was to examine the influence of corn on stink bugs (Heteroptera: Pentatomidae), Nezara viridula (L.), and Euschistus servus (Say), in subsequent crops in these farmscapes. Adults of both stink bug species entered corn first, and seasonal occurrence of stink bug eggs, nymphs, and adults indicated that corn was a suitable host plant for adult survival and nymphal development to adults. Stink bug females generally oviposited on cotton or peanut near the interface, or common boundary, of the farmscape before senescence of corn, availability of a new food, or both. Adult stink bugs dispersed from crop to crop at the interface of a farmscape in response to senescence of corn, availability of new food, or both. In corn-cotton farmscapes, adult stink bugs dispersed from senescing corn into cotton to feed on bolls (fruit). In corn-peanut farmscapes, adult stink bugs dispersed from senescing corn into peanut, which apparently played a role in nymphal development in these farmscapes. In the corn-cotton-peanut farmscape, stink bug nymphs and adults dispersed from peanut into cotton in response to newly available food, not senescence of peanut. Stink bug dispersal into cotton resulted in severe boll damage. In conclusion, N. viridula and E. servus are generalist feeders that exhibit edge-mediated dispersal from corn into subsequent adjacent crops in corn-cotton, corn-peanut, and corn-peanut-cotton farmscapes to take advantage of suitable resources available in time and space for oviposition, nymphal development, and adult survival. Management strategies for crops in this region need to be designed to break the cycle of stink bug production, dispersal, and expansion by exploiting their edge-mediated movement and host plant preferences.     

The effects of crop rotation and fertilization on soil xylanase activity in a soil of the southeastern United States

Summary Xylanase activity was determined in soils from a 3-year rotation with corn, (Zea mays L.), cotton (Gossypium hirsutum L.), and soybean (Glycine max (L) Merr.) as summer crops at Auburn, Alabama, in the southeastern U.S.A. Winter wheat (Triticum aestivum L.) followed corn and a period of winter fallow as maintained after soybeans. A combination of common vetch (vicia sativa L.) and crimson clover (Trifolium incarnatum Gibelli & Belli) followed cotton during the winter months to serve as green manure. Highest xylanase activity was detected after soybeans and lowest after cotton among the summer crops. The culture of wheat and winter legumes resulted in increased soil xylanase activity wheareas winter fallowing reduced the activity. The effect of various fertilization schemes superimeposed on the rotation on soil xylanase activity was also studied. Seasonal fluctuations in soil xylanase activity were not affected by the fertilization regimes and highest xylanase activities were observed during crop periods and with fertilization treatments that resulted in high root densities but not necessarily in high yields.     

甘薯质体中的乙酰辅酶A羧化酶亚基基因accD的克隆与序列分析

依据烟草质体全基因组序列设计引物,以甘薯质体基因组DNA为模板,PCR扩增包含质体accD基因完整编码区在内的一段序列（GenBank登录号为GQ395771）。序列分析表明：该片段全长为2209bp,包括1548bp的nccD基因编码序列,推测编码515个氨基酸的蛋白质,该蛋白序列具有异质型β-CT中保守的锌指结构和C末端5个基元。同时绘制了该DNA片段的限制性酶切图谱。相似性比较显示,甘薯accD基因与大豆、马铃薯、拟南芥、人参、莴苣、葡萄、海岛棉、甘蓝、辣椒、菠菜、番茄和烟草的accD基因核苷酸相似性为72％-87％,氨基酸相似性为58％-83％。     

Stimulation of glutathione synthesis in photorespiring plants by catalase inhibitors

The effect of various herbicides on glutathione levels in barley (Hordeum vulgare L.), tobacco (Nicotiana tabacum L.), soybean (Glycine max [L.] Merr.), and corn (Zea mays L.) was examined. Illumination of excised barley, tobacco, and soybean plants for 8 hours in solution containing 2 millimolar aminotriazole (a catalase inhibitor) resulted in an increase in leaf glutathione from 250 to 400 nanomoles per gram fresh weight to 600 to 1800 nanomoles per gram fresh weight, depending on the species tested. All of this increase could be accounted for as oxidized glutathione. Between 25 and 50% of this oxidized glutathione was reduced when plants were darkened for 16 hours, but there was no significant decline in total glutathione. Another catalase inhibitor, thiosemicarbazide, was as effective as aminotriazole in elevating glutathione in soybean but was less effective in barley and tobacco. Glyphosate, an inhibitor of aromatic amino acid biosynthesis, had no significant effect on glutathione levels in any of the plants examined. Whereas methyl viologen (paraquat), which is a sink for photosystem I electrons, caused oxidation of leaf glutathione in all of the plants but did not increase the total amount of glutathione present.     

烟粉虱在烟株上的垂直分布及寄主选择性

烟粉虱是云南省农业生产上的重要害虫之一。通过田间系统调查和室内观察相结合,研究了烟粉虱在烟株上的垂直分布特性和在8种寄主作物上的取食、产卵趋性。（1）烟粉虱在烟株上的垂直分布特征为上部＞中部＞下部,8月中旬为种群高峰期,上、中、下部叶片的成虫密度分别为15．1、10．9、6．7头？片-1;（2）烟粉虱成虫的取食趋性表现为大豆＞南瓜＞甘薯＞番茄＞一品红＞茄子＞甘蓝＞烟草,各处理间差异不显著（P＞0．05）;（3）产卵趋性表现为一品红＞大豆＞南瓜＞甘薯＞番茄＞茄子＞甘蓝＞烟草,一品红与南瓜、甘蓝、茄子、甘薯、番茄、烟草处理间,以及大豆与烟草处理间存在显著差异（P＜0．05）,其他处理间差异不显著（P＞0．05）。在所测定的8种寄主植物中,烟粉虱成虫对烟草的选择性最差,烟区规划烟田种植范围时,应避免与大豆、南瓜、甘薯、番茄等作物间作或距离太近。