广西兴安地区褐飞虱发生动态及迁飞轨迹分析

为明确广西兴安地区单双季稻混作模式下褐飞虱发生规律,采用灯光诱捕和田间系统调查的方法研究了该地区早、中、晚稻田褐飞虱发生动态,并运用大气质点轨迹分析平台HYSPLIT 4.8对2011年褐飞虱迁飞高峰进行了迁飞轨迹分析。广西兴安地区褐飞虱种群数量随季节变化明显,年发生6代,迁飞活动主要集中在7月上旬至9月上旬。褐飞虱发生高峰期与单季中稻生长期吻合,在单季中稻田的发生量最大。2011年广西兴安褐飞虱5—6月迁入虫源主要来自海南稻区以及泰国、越南和老挝中部稻区;7—8月迁入虫源来自广西南部、东南部和广东西部稻区;回迁虫源来自湖南西南部和江西西部;10月从本地迁出的虫群主要迁向广西中部和贵州南部。研究表明,偏南方向的低空急流为褐飞虱的大规模迁入提供了运载气流,降雨是迫使稻飞虱降落的主要原因。     

广西兴安地区稻纵卷叶螟早期迁入虫源分析

运用大气质点轨迹分析平台HYSPLIT 4.8对2007-2011年广西兴安地区早期灯下稻纵卷叶螟Cnaphalocrocis medinalis Guenée主要迁入峰进行了轨迹模拟,并运用气象图形处理软件GrADS对迁飞高峰期进行气象背景分析。结果显示,广西兴安地区稻纵卷叶螟于5月初开始零星迁入,迁入高峰期集中在5月下旬至6月下旬,最大迁入峰集中在6月中下旬。诱虫量及迁入峰次年度间存在差异。广西兴安地区稻纵卷叶螟5月迁入虫源主要来自海南中部、西南部,老挝和泰国北部,广西南部、广东西南部也能提供部分虫源。6月迁入虫源主要集中在广西南部、广东西南部、海南中部、老挝中部稻区,越南中部稻区也能提供部分虫源。稻纵卷叶螟迁入峰期925 hPa等压面上气流方向均为较强的西南或偏南气流。降雨和气流的垂直扰动导致稻纵卷叶螟大规模迁入降落。     

水稻种植制度变化对褐飞虱暴发种群形成的影响

自20世纪90年代以来,江南稻区北部(涉及江苏、浙江、安徽、江西、湖南、湖北六省)不同程度地开展了双季改单季的水稻种植制度的调整,为了阐明水稻种植制度变化对褐飞虱暴发种群形成的影响,2007、2008年在怀宁县和潜山县采用田间调查与卵巢解剖等方法研究了单季中稻、双季晚稻中褐飞虱的种群动态及世代虫源性质。结果表明:安庆地区单季稻大面积种植后,6月中旬至7月下旬迁入的褐飞虱可以直接降落在单季中稻本田,并能连续繁殖,种群增殖倍数可高达数百倍,单季中稻褐飞虱的发生量高于双季晚稻;卵巢解剖确定了单季中稻及双季晚稻中褐飞虱各世代的虫源性质,单季中稻褐飞虱迁出盛期在8月下旬至9月中旬,可以为长江三角洲后期迁入提供虫源,也可以在本地作近距离的扩散迁移,加重对双季晚稻的危害。皖南地区单季稻种植面积的扩大,不但显著增加了本地单季中稻、双季晚稻中褐飞虱的种群数量和危害程度,而且也导致了近年来长江三角洲地区频繁出现褐飞虱的后期迁入。因此,水稻种植制度的变化对褐飞虱暴发种群的形成具有决定性的作用。     

基于WRF-FLEXPART模式的广西兴安县白背飞虱迁入过程分析

为明确白背飞虱Sogatella furcifera(Horváth)迁入种群的中小尺度虫源地和降落机制,提高白背飞虱异地预测的精确度,2012年在广西兴安县应用探照灯诱虫器对白背飞虱进行了分时段监测;选取2012年6月4日至6月10日广西稻区的一次白背飞虱北迁过程作为典型个例,并运用中尺度气象预报WRF模式和FLEXPART模式进行大气背景分析和白背飞虱迁飞轨迹模拟。结果表明:低空急流为此次迁飞过程提供运载气流,下沉气流、降雨、气温屏障使白背飞虱聚集降落;此次迁入白背飞虱虫源地主要包括越南北部的木州、原平和平卢,以及广西的博白县和上思县。表明通过WRF-FLEXPART模拟平台进行白背飞虱迁飞路径的研究是可行的。     

我国西南稻区白背飞虱,褐稻虱的迁飞和发生特点

由于西南稻区的地理位置、地势、地形、气候和水稻种植制度等因素的影响,白背飞虱和褐稻虱的迁飞和发生情况与我国东部稻区相比较,有其不同的特点: 迁飞特点有:贵州东南部迁入期较早,全区迁入虫量大,白背飞虱为春季迁入的优势种;云南境内,从南向北地势逐步抬升,迁入期和主要为害时期亦逐渐推迟,虫种由褐稻虱较多而变成白背飞虱为优势虫种;四川盆地迁入始期和主要迁入期由东向西推进;主害代的迁入虫源路径多;夏季短、中距离的迁飞频繁,有的年分在中稻上常造成两次主害时期等。发生特点有:常年三省的东、南部地区发生程度重,三省的西、北部地区发生程度轻;近期迁入虫量是中稻或晚稻上主害代的主要虫源;虫量相应集中,加重为害程度;另方面天敌种类多,数量较大,对飞虱种群数量有一定的抑制作用。上述迁飞和发生特点可作为拟定西南稻区对两种稻飞虱预测预报和防治策略的理论依据。     

桂东北稻区褐稻虱、白背飞虱发生规律研究

桂东北稻区包括桂林地区、桂林市及柳州和梧州两地北部稻区,稻田面积四百多万亩,南部为双季稻区,北部以双季稻为主并有一定面积的中稻,属单双混栽区,由于本稻区地理位置、生态环境、气候条件特殊,褐稻虱、白背飞虱大发生频率高,已成为主要为害区.是水稻上急待解决的问题,近年来,通过全国科研协作,探明了褐稻虱、白背飞虱均属迁飞性害虫,本稻区既承受外地褐稻飞、白背飞虱迁入为害,又是继续迁往长江流域广大稻区的虫源基地,为此,从1983年起,笔者在主持南岭稻区迁飞性害虫科研协作工作的同时,对桂东北稻区褐稻虱、白背飞虱在早晚稻的消长规律、种群数量变动规律,以及迁飞规律都进行了研究.尤其是探明9月回迁峰次比8月份频率高.9月上中旬回迁虫源在晚稻上仍能繁殖一代,对主害代发生量有一定影响.9月底回迁虫源因北部稻区晚稻已基本成熟,营养条件不利,加之,10月上中旬气温逐渐降低对稻飞虱生长发育不利,因而,这部分回迁虫源对晚稻为害损失不大,但对南部稻区迟熟品种仍有一定影响.从而对测预预报和防治提供了科学依据.     

未雨绸缪运筹帷幄大打有备之战——2007年广西早稻"两迁"害虫防控纪实

发生概况稻飞虱具有大区域迁飞、暴发性和灾害性特点，是广西水稻上诸多病虫害中发生面积最大、为害最重的农业有害生物。据有关专家研究结果：中南半岛的越南为迁入我国的褐飞虱的主要虫源地，早春稻飞虱随西南气流从越南北部迁入广西，经繁殖后，产生的长翅型成虫逐渐北迁至长江流域、淮河流域等地；8月下旬至10月上旬，随南向气流逐渐从江淮、长江稻区往南回迁。稻飞虱在广西一年可发生7～8代，有明显的世代重叠现象。近年来，由于气候变异、耕作制度改变等综合因素的影响，稻飞虱在广西暴发频率增加。今年5月上中旬，广西桂东南、桂西南…     

对智能无人直升机防控稻飞虱的初步评价

稻飞虱是水稻的主要害虫,大冶地区一年发生5代,种类以褐飞虱和白背飞虱为主,灰飞虱为辅.常年第三(1)代白背飞虱、褐飞虱主峰迁入在5月～6月,以迁入量和种群比例决定当年的发生程度;第四(2)代稻飞虱发生期为6月下旬至7月中旬,以白背飞虱为优势种群,常造成迟熟早稻穿顶、枯秆;第五(3)代稻飞虱发生期正值高温季节,白背飞虱种群数量呈下降趋势,褐飞虱种群数量逐步上升,进入8月上旬以后,如盛夏不热,阵雨较多,田间短翅型成虫比例高,褐飞虱迅速繁殖成为优势种群;9月上、中旬,第六(4)代褐飞虱常在中稻田造成为害,出现中稻、一季晚稻大面积穿顶倒伏;第七(5)代褐飞虱发生情况较复杂,大多年份晚秋气温较高,有利本地虫源大量繁殖,加上北方中稻收割后大量褐飞虱向南回迁,遇适合气候条件大量成虫降落我市继续为害,常造成双季晚稻、迟熟一季晚稻大面积倒伏.     

安庆地区南方水稻黑条矮缩病田间发生特征研究

对南方水稻黑条矮缩病田间症状类型、症状表现时间、不同时间种植类型水稻发病差异、当前主要发病品种(或组合)、白背飞虱在本地发生规律、田间病丛分布特征等进行了初步研究.结果表明,南方水稻黑条矮缩病的症状有典型和非典型、重症和轻症之分;在双季早稻、中稻、单季晚稻和双季晚稻混栽地区,以中稻、单季晚稻和双季晚稻发生较普遍,早稻发病较轻,这与白背飞虱在本地的发生期同各种时间种植类型水稻易感病生育期吻合程度有关;不同类型水稻发病程度不同,籼型杂交稻发病重于常规梗、糯稻,似与白背飞虱嗜食杂交稻的习性有关;品种间发病程度有差异,如奥两优28、华安3号等部分品种发病严重;病丛(株)在田间呈聚集分布.     

河池市稻飞虱的发生与防治简报

在河池市危害水稻的稻飞虱主要有白背飞虱、褐飞虱。早春主要虫源由东南亚随西南气流迁入,秋季随东北气流由北回迁。褐飞虱和白背飞虱在河池一年可发生7～8代,其中主要危害代为第2～6代,对水稻造成危害重、损失大,不防治的田块可颗粒无收。第1代发生在3月份,第2代发生在4～5月间,第3、4代发生在6月中旬至7月上旬,这时正值早稻孕穗、抽穗、灌浆期,第5、6代发生在8月下旬至9月中旬或10月上旬,     

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.     

彭泽县2005年棉铃虫的发生特点及分析

2005年彭泽县的棉铃虫在棉田的发生表现出发生时间早、产卵密度前期偏高,后期则明显偏低、各代间蛾、卵的消长关系极不平衡、发生面积小、发生程度轻的特点,其主要受其种群的消长、气候及棉田的管理等因素的综合影响。     

Effects of temperature onPhytophthora porri in vitro,in planta,and in soil

Cardinal temperatures for mycelial growth ofPhytophthora porri on corn-meal agar were <5 (minimum), 15–20 (optimum) and just above 25 °C (maximum). The number of infections after zoospore inoculation of young leaf plants was relatively low at supra-optimal temperatures, but was not affected by sub-optimal temperatures. Even at 0 °C plants were infected. The incubation periods needed for symptom formation were 36–57 d at 0 °C, 13–18 d at 5 °C, and 4–11 d at > 11 °C, and were fitted to temperature between 0 and 24 °C with a hyperbolical model (1/p=0.00812^*T+0.0243). Oospore germination, reported for the first time forP. porri, was strongly reduced after 5 h at 45 °C, and totally absent after 5 h at 55 °C. Soil solarization for six weeks during an exceptionally warm period in May–June 1992 in The Netherlands raised the soil temperature at 5 cm depth for 17 h above 45 °C, but did not reduce the initial level of disease in August significantly.     

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.     

中国鼠害防控需求的差异、矛盾、挑战与对策

绝大多数啮齿动物种类为植食性的小型哺乳动物，其生物学特性导致了鼠类危害的复杂性。当前，面对日益提高的生态安全需求，粮食安全、人民健康和生物安全以及生态安全对鼠害控制需求的差异造成了中国鼠害防控策略制定及实施的困扰。尤其在草原地区，如何在应急性灭杀和长效缓控之间找到一个平衡点是目前鼠害防控面临的一个巨大挑战。针对这些矛盾和挑战，该文分析了我国鼠害监测防控的现状、主要瓶颈与短板，并从技术层面提出“精准监测指导精准防控”可能会是解决这些矛盾的有效途径，是在有效控制鼠害暴发对粮食生产和人民健康安全威胁的前提下，推进生态保护和修复的有效途径。     

Metabolism of the methoxychlor isostere,dianisylneopentane, in mouse,insects, and a model ecosystem

Dianisylneopentane or 1,1-bis(p-methoxyphenyl)-2,2-dimethylpropane was metabolized largely by O-demethylation to form mono- and diphenol derivatives. Only a small percentage was degraded by α-hydroxylation and rearrangement. In the model ecosystem, dianisylneopentane reacted very similarly to methoxychlor, accumulating in fish to about the same extent and yielding a slightly higher ratio of polar to nonpolar metabolites. The neopentyl group proved to be approximately as stable in biological systems as the isosterically equivalent trichloromethyl group.     

Induction, Regulation, and Role in Pathogenesis of Appressoria in Monilinia fructicola

ABSTRACT Monilinia fructicola, which causes brown rot in stone fruit, forms appressoria on plant and artificial surfaces. On nectarine, the frequency of appressoria produced by conidial germlings depends to a large degree on the stage of fruit development, with numerous appressoria formed on immature (stage II) nectarine fruit, and no appressoria observed on fully mature fruit (late stage III). On polystyrene surfaces, appressorium formation was increased from <10% of germinated conidia to >95% of germinated conidia when the conidia were washed to remove residual nutrients and self-inhibitors. M. fructicola appressorium formation also appears to be regulated by the topography of the plant surface. On fruit, appressoria formed on stomatal guard cell lips, on the grooves of lateral cells adjacent to stomata or between two epidermal cells, and on the convex surfaces of epidermal cells. Pharmacological effectors indicate that cyclic AMP-, MAP kinase-, and calcium/calmodulin-dependent signaling pathways are involved in the induction and development of appressoria. KN-93, an inhibitor of calmodulin-dependent protein kinase II, did not inhibit conidial germination but did inhibit appressorium formation and brown rot development on flower petals, suggesting that appressoria are required for full symptom development on Prunus spp. petals.     

Adsorption-desorption studies of alachlor, metolachlor, EPTC, chlorothalonil and pirimiphos-methyl in contrasting soils

Five soils with different organic matter contents ranging from 0.48 to 10.4% were used to study the adsorption and desorption of alachlor, metolachor, EPTC, chlorothalonil and pirimiphos-methyl in batch experiments. The isotherm shapes according to Giles classification were S-type for alachlor, metolachlor and chlorothalonil, changing to L-type for the latter as the level of soil organic matter increased, and L-type for EPTC and pirimiphos-methyl. The adsorption isotherms fitted the Freundlich equation x/m = KfCe1/n. The Kf values increased with the increase of organic matter content. The amounts of pesticides adsorbed over a range of concentrations of 0.1-20 mg litre-1 reached 63.1% for alachlor, 69.2% for metolachlor, 89.3% for EPTC, 98.4% for chlorothalonil and 96.3% for pirimiphos-methyl. The increase of the amounts desorbed with acetone indicated that the sorption of organic compounds onto organic matter occurred principally via weak London-type induction forces, or dispersion forces which are characteristics of the physical adsorption process.     

Establishment of, and preliminary impact studies on, the rust, Maravalia cryptostegiae, of the invasive alien weed, Cryptostegia grandiflora in Queensland, Australia

The rust fungus Maravalia cryptostegiae , from south-west Madagascar, was introduced into Australia in 1995 as a classical biological control agent against the highly invasive rubber-vine weed Cryptostegia grandiflora , a woody climber endemic to Madagascar. The rust was released at 69 sites between 1995 and 1997 and is now established throughout the plant's exotic range in Queensland, estimated at over 40 000 km². Dispersal was low in the first 3–4 months but was virtually linear thereafter, and the rust spread over 100 km within the first year; after 3 years it was recorded 550 km away from the nearest release site. Spraying both dry and aqueous inoculum of uredinioid teliospores from the ground using mist-blowers, as well as from the air by atomizing spore suspensions, resulted in rust-induced defoliation, producing an overall reduction in fecundity and biomass of the weed. In sites with low water tables, weed growth decreased markedly, with a reduction in plant volume from 9 m⁻³ to 1 m⁻³ over a 4-year period. Both rust- and drought-induced stress combined to cause up to 75% plant mortality at some sites, and at all monitored sites, seedling recruitment was virtually nil. Improved growth of indigenous grasses amongst rubber-vine thickets has increased fuel loads and created opportunities to use fire as a component of an integrated approach to the management of this economically and ecologically damaging weed.     

Organochlorine residues in fish, water, and sediment of American Falls Reservoir, Idaho, 1974.

Organochlorine residues of TDE, DDE, and PCBs as high as 1.96, 2.79, and 28.74 microgram/kg, respectively, have been found in sediments of American Falls Reservoir, Idaho. Residues of TDE, DDE, and dieldrin in the flesh of sport fish were as high as 52.3, 67.2, and 160.4 microgram/kg, respectively. Maximum organochlorine residue levels found in sucker taken in the commercial fishery were 1.1 mg PCBs/kg, 781.7 microgram TDE/kg, and 82.1 microgram DDE/kg.