外施硅肥与灌溉方式对草地早熟禾白粉病病情的影响

为探索硅肥与灌溉方式对草地早熟禾(Poa pratensis)白粉病的防治效果,试验通过室内盆栽研究了外施硅肥与根灌对草地早熟禾白粉病病情的影响。结果表明,根灌对草地早熟禾白粉病病害的抵制作用不明显并具分异性;对于患病较重的禾草,根灌会使病情加重。外施SiO2溶液可以显著减轻草地早熟禾白粉病的病情指数和病害程度(P＜0.05)。在试验设定的硅肥梯度(0、31、92、275 mg/m2)内,随着施硅量的增加,病情的减轻愈显著。     

木醋液对有机烟草产质量及病害的影响

通过田间小区试验,将木醋液施入植烟土壤和叶面喷施,研究了木醋液对有机烟草产量和品质的影响,探讨木醋液对有机烟草生长及品质改善方面的作用。研究结果表明：施用木醋液增加了有机烟草产量和产值,根施150 kg/hm²和叶面喷施稀释1000倍木醋液处理效果最好,分别使产量增加了32.0%和25.4%,产值增加了52.0%和32.4%。对有机烟草的茎围没有明显影响,但在烟草打顶期可增加烟草的株高和最大叶面积。明显提高了有机烟叶钾含量,叶面喷施稀释1000倍木醋液处理比对照增加了1.44%,并且叶面喷施的效果要优于根施,有机烟叶的有机物质总糖、还原糖、烟碱含量适中,化学成分比例更协调。明显降低了有机烟草普通花叶病和黑胫病的发病率,对烟草白粉病没有影响。     

暗纹东方鲀集约化养殖中的几种常见疾病的诊断、治疗及防治

本文报道了1995～1998年间作者在暗纹东方鲀集约化养殖中,对小瓜虫病、鲀异钩虫病、指环虫病、车轮虫病及细菌性疾病进行的诊断、治疗及防治方法,同时描述了各病的典型症状。本文为鉴别、治疗、防范暗纹东方鲀鱼病提供了依据,在集约化养殖中具有一定的应用价值。     

贵州马铃薯病害调查研究

为了明确贵州马铃薯生产中病害的发生和流行规律,2008-2010年对贵州马铃薯主产区病害发生及流行情况进行调查研究。结果发现,有19种的病害为害马铃薯,包括真菌病害8种,细菌病害4种,病毒病4种,放线菌病害1种,非侵染性病害2种。其中发生较为普遍的病害有晚疫病、生理性叶斑病、早疫病、病毒病（潜隐花叶病毒病）、青枯病、炭疽病和生理性早衰等7种,其中马铃薯晚疫病发生和危害最重。各种病害的发生时间与严重程度取决于当地气候条件、品种特性和播种时期。     

炸片专用马铃薯高产品种引进筛选与性状比较试验研究

为了生产符合炸片加工对薯块块茎品质的特殊要求的炸片专用优质马铃薯品种,采用品种筛选与性状比较的方法,研究多种马铃薯品种的炸片品质。结果表明‘大西洋’品种具有较好的加工特性和丰产性,但是抗病性与抗逆性较弱;‘夏波蒂’、‘东农305’、LK99等品种综合品质仅次于‘大西洋’品种。从块茎外观、品质、炸片质量、丰产性、抗病性、生育期等性状综合评价,‘大西洋’品种仍然是炸片马铃薯的当家品种,更适合于马铃薯加工。     

肉用雏鸡新城疫血清抗体与免疫保护关系研究

采用鸡新城疫强毒F48E9,对新城疫血清HI效价分别为1：64-1：8的9日龄健康雏鸡进行攻毒,观察各组雏鸡的发病和死亡情况。根据所得数据确定ND抗体保护的临界范围。     

辽宁地区樗蚕的生物学特性及人工饲育技术研究

樗蚕(Samia cynthia Walker et Felde)是一种珍贵的泌丝及食用昆虫资源。通过室内及野外人工饲育的方法,观察分布在辽宁地区的樗蚕的形态特征和生活习性,发现与分布于其它地区的樗蚕存在不同程度的差异。辽宁地区的樗蚕年发生1-2代,喜食臭椿(Ailanthus altissima)、山花椒(Zanthoxylum schinifollum)、枣树(Zizyphus jujube)、黄檗(Phellodendron amu-rense)等的树叶,幼虫4眠5龄,龄期经过25-37d,饲料种类不同可造成龄期差异;以蛹滞育。人工饲育樗蚕可采用小蚕室内育,大蚕野外育的饲养形式;种茧保护可采用柞蚕(Antheraea pernyi)的种茧越冬保护技术与方法,春季种茧出库后在温度20～23℃、相对湿度75%～85%的条件下暖茧,成虫交配时间超过4h的卵孵化率较高;樗蚕的主要病害有细菌性软化病、白僵病、微粒子病,春、秋季野外饲养的樗蚕易被蚕饰腹寄蝇(Blepharip azebina)寄生危害。樗蚕茧丝的纤度为1.80～3.60dtex,茧层丝胶练减率平均为25%,茧丝中的丝素蛋白约78%。     

Variation in resistance to the Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) in Pietrain and Miniature pigs

Porcine reproductive and respiratory syndrome (PRRS) is one of the economically most important diseases of swine. Viraemia and the prolonged persistence of the virus are among the most critical factors. Virus replication and severity of disease vary with virus isolates, and there is rising evidence for a genetic component of the host susceptibility. Dissecting the genetic basis of resistance/susceptibility to PRRS virus (PRRSV) might lead to improved knowledge on the molecular mechanisms of PRRS and the establishment of genetic markers for future disease control. The aim of this study was to establish a porcine model with emphasized genetic differences in PRRSV susceptibility. Seven ‘Wiesenauer Miniature’ pigs (MI), a local German breed and eight commercial Pietrain (PI) pigs were challenged with 10⁵ TCID₅₀ of an attenuated PRRSV strain (Ingelvac^® PRRSV MLV). Clinical status, viraemia and seroconversion of the pigs were compared. No clinical signs were observed during the experiment. Viraemia peaked on day 6 p.i., with 100% of viraemic pigs in PI and on day 12 p.i with 87% of viraemic MI. Viraemia lasted for up to 35 days in MI and for at least 72 days in PI. This surprising result was confirmed by a second study with another four MI. MI and PI showed maximum virus titres of 10^2.5 TCID₅₀/ml of serum and 10^4.5 TCID₅₀/ml, respectively, indicating a virus replication in MI of approximately 3.3% that of PI over the complete period. MI were more efficient in antibody production. With such pronounced breed differences, the model is of high relevance for the genetic dissection of PRRS pathogenesis and susceptibility.     

Economic impact of Wheat streak mosaic virus in the Texas High Plains

Wheat streak mosaic virus, vectored by the wheat curl mite Aceria tosichella Keifer, is a major limiting factor in wheat production in the Texas Panhandle. It is the most frequently encountered virus in the region, affecting both shoot and root biomass, and consequently it can drastically reduce both forage and grain yield, and water-use efficiency of the plant. In light of the continuing decline of water levels in the Ogallala Aquifer, its effect on water-use efficiency has significant implications for irrigated fields, especially with regard to energy costs for pumping water. This article estimates the potential economic losses from the virus infection. To achieve this objective, partial budgeting techniques, based primarily on data from field experiments, were used. Results indicate that Wheat streak mosaic virus causes grain and forage yield losses that significantly affect profits from wheat production. In addition, irrigated wheat producers are more negatively affected by the disease due to the economic losses from reduced water-use efficiency of infected plants. The economic insights from this article provide important implications for wheat management and research priority-setting.     

麦烟套种综合利用研究

[目的]研究贵州省铜仁地区高产高效的粮经型栽培模式,实现植烟土地的合理利用。[方法]以川农麦1号为供试小麦品种,采用3行麦、2行烟的麦烟套种模式,研究麦烟套种对植烟环境和烟叶产量、产值及病虫害的影响。[结果]麦烟套种明显减轻烟株马铃薯Y病毒病（PVY）的发生,单作烟马铃薯Y病毒病的发病率是麦套烟发病率的近15倍;麦烟套种可增加纯收入1467.6元/hm2;秸秆覆盖与否对烟叶等级比例、产量、产值和均价没有明显的影响。[结论]在贵州铜仁地区采用麦烟套种技术可减少烟叶病虫害,增加经济收益,提高土地利用率。