海南西瓜枯萎病防治的现状和展望

西瓜枯萎病是一种土传病害,在世界各地均有发生,成为西瓜生产的主要限制因子。作者根据多年实践并参考有关资料,对海南西瓜枯萎病的防治现状和未来发展方向进行了综述。     

养殖农户报告动物疫情行为意愿及影响因素分析——以湖北地区养殖农户为例

养殖农户拥有动物健康状况信息,是否主动报告动物疫情直接影响动物疫病从发现到大规模爆发的时间间隔,进而影响重大动物疫情的传播速度和严重性。运用有序Logistic模型对影响养殖户上报疫情行为意愿的因素进行实证研究,结果表明:责任分散效应、扑杀补偿激励不足、防疫意识淡薄是养殖户不上报疫情的主要原因;饲养规模较大、对动物疾病情况较为了解的养殖户上报动物疫情行为意愿较弱;具有较高文化程度、接受了当地畜牧部门培训、参加了养殖协会、对动物产品安全较为忧虑、认为政府扑杀补贴能较大程度弥补扑杀带来的损失等特征的养殖农户上报疫情行为意愿较强。     

香蕉束顶病的研究 Ⅰ.病害的发生、流行与分布

香蕉束顶病广泛分布于福建省漳州、厦门、泉州、莆田、福州及龙岩等地(市)所辖的大部分县(市)的香蕉产区,达23个县(市、区)之多,分布北界已达福州,且有继续向西、向北推移之势。发病率因地区、年份不同以及是否采取防治措施等而有差异,从零星发病至30％—50％不等,严重者达70％-80％,甚至不得不毁园再植或改种其它作物。该病发生一般以4～6月份最烈,系发病高峰期。病害发生的轻重与品种类型、蕉苗质量、种植年限、生育龄期、蕉蚜数量、栽培管理措施、气候、土壤和地理位置等均有关系。大量种植带病蕉苗是病区迅速扩展的直接原因;介体蕉蚜活动猖獗和管理粗放是病害严重发生和流行的主导因素。     

Effects of heavy metals and acid irrigation on the birch rust,Melampsoridium betulinum

Effects of simulated acid rain and heavy metals on the occurrence of Melampsoridium betulinum in naturally infected mountain-birch trees and seedlings (Betula pubescens subsp. tortuosa) were studied in a subarctic area where background polution levels are low. The short term (2 years) effects of copper, nickel and sulphuric acid, and long term (8 years) effects of nitric- and sulphuric-acid deposition on birch-rust infection were determined.     

Spatial patterns of leprosis and its mite vector in commercial citrus groves in Brazil

In order to describe the dissemination of Citrus leprosis virus (CiLV) and Brevipalpus phoenicis , the Tenuipalpidae mite which transmits it, as well as to generate data for future development of better sampling and disease control procedures, analyses were conducted at three levels of spatial hierarchy. Over 100 distribution maps of mite-infested plants and plants with CiLV symptoms were constructed after evaluation of 174 sweet orange commercial grove blocks from four citrus regions of São Paulo State, Brazil. Spatial correlation between maps of mite-infested plants and those with CiLV symptoms was very low and mostly not significant. Spatial dependency between adjacent plants was incipient as ordinary runs analysis showed that percentages of aggregated sequences within or across rows were very low for both mite-infested and diseased plants. Index of dispersion ( D ) values for all quadrat sizes suggested aggregation of plants with symptoms within quadrats, but much less aggregation for mite-infested plants. Values of log( A ) and b were higher than 0 and 1, respectively, indicating a general and significant aggregation of infested/diseased plants inside quadrats. However, the degree of aggregation of plants with symptoms was higher than that of infested plants. Aggregation in each grove was positively correlated to the incidence of infested/diseased plants. Spatial autocorrelation also showed a higher strength of aggregation for plants with symptoms than for infested ones. This is the first time that spatial patterns of leprosis and B. phoenicis have been described.     

唐松草作为小麦叶锈菌的转主寄主问题的研究

1984年在内蒙古卓资县白石头沟野外调查中发现4种唐松草和5种禾本科杂草都发生有叶锈病。但无迹象表明该地区自然界唐松草上发生的叶锈病与小麦叶锈病有关。在室内用小麦、华北剪股颖和无芒雀麦叶锈菌的冬孢子对亚欧和瓣蕊唐松草接种,都长出了锈孢子腔和锈孢子。用三种锈孢子分别对小麦、华北剪股颖和无芒雀麦回接,都产生了夏孢子,完成了生活循环。从此得出结论:亚欧和瓣蕊唐松草是小麦、叶锈菌的转主寄主,但在室外不起作用。而田间所见唐松草上的锈病主要与杂草上的锈病有关。     

Aster albescens Rust Caused by Aecidium asterum and Its Hyperparasitic Fungus Tuberculina persicina

Aster albescens is a medicinal plant. The rust caused by Aecidium asterum is a new record in China and an important disease of A. albescens in Feng Tong-zhai national reservation area. The percentages of diseased plant and the diseased leaf reach 100 and 28% respectively when the disease is serious. The disease results in leaf spot and leaf cast. Tuberculina persicina is a natural hyperparasite of A. asterum and is firstly reported in the world. The hyperparasite attacks aecium of A. asterum and hinderes the release of aeciospores. The symptom of the rust and the morphological characteristics of A.asterum is reported. The hyperparasitism of A. asterum and the morphological characteristics of the Tuberculina persicina are also reported.     

Landraces of cowpea, <Emphasis Type="Italic">Vigna</Emphasis><Emphasis Type="Italic">unguiculata</Emphasis> (L.) Walp., as potential sources of genes for unique characters in breeding

Cowpea landraces belonging to Vigna unguiculata (L.) Walp. subsp. unguiculata cv.-gr. unguiculata and cv.-gr. sesquipedalis collected from part of the Deccan Plateau and West Coast of India were evaluated to (i) identify the diverse source(s) of variation for improved characters like pods/peduncle and seed index (ii) study the response of landraces for adaptation to drought and heat stress and (iii) understand the breeding value of a landrace in the genetic improvement of a popular cowpea cultivar. Landraces were evaluated for various morphological characters, pods/peduncle, seed index and other economically important agronomic traits, rust resistance and drought and heat tolerance in different years and environments. Landraces were found as an important source of genetic variability for pods/plant, pods/peduncle, better pod filling ability (seed index), grain yield/plant as well as drought and heat tolerance and rust resistance. Hybridization between C 152 (cv.) and DWDCC 016 (landrace) resulted in release of new variation not present in the two parents. Thus the landrace, DWDCC 016, can be utilized to improve cultivated varieties by transferring to them the economically valuable traits like pods/peduncle and seed index thereby enhancing realisation of sink potential and ultimately grain yield in a sustainable way.     

4种猪繁殖障碍性疫病流行病学调研与分析

猪繁殖障碍性疫病严重危害养猪业的发展,为了查清山西省这些疫病的流行情况,对全省8个地市42个规模化种猪场进行了流行病学调查,发现因母猪繁殖障碍病造成死亡的仔猪数平均可以占到总产仔数的13.77%,同时采集病料组织257份,不同日龄猪群血清1776份,用不同病原的PCR和ELISA试剂盒对猪瘟、猪繁殖与呼吸综合征、猪伪狂犬病和猪圆环病毒2型等进行了病原和抗体检测,结果表明,猪瘟病毒感染率为28.4%,抗体阳性率为57.55%;猪繁殖与呼吸综合征感染率为3.89%;猪繁殖与呼吸综合征变异株感染率为39.69%,抗体阳性率为44.99%;猪伪狂犬病病毒感染率为10.12%;gE抗体阳性率为2.98%,gB抗体阳性率为76.35%;猪圆环病毒2型感染率为15.18%,抗体阳性率为56.98%,证明山西省种猪场4种疫病感染较为严重,并且常常发生混合感染,为今后山西省防控这些疫病提供了依据。