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61.
环青海湖地区草地蝗虫发生测报的气候指标研究   总被引:7,自引:0,他引:7       下载免费PDF全文
采用次序统计量方法,以1988~1999年环青海湖地区草地蝗虫发生程度资料和气候资料研究了蝗虫灾害等级与当地气候指标的定量关系,建立了春季和夏季预测模型,并以此对2000~2003年该地区蝗虫发生状况进行了预测试验。结果表明,敏感气候因子有:上年11~12月气温、3~6月温度及5~6月降水量等。春季预测模型中的指标为:(1)T11<-6℃;(2)T12<-10℃;(3)T3>-4℃;(4)T4>2℃。夏季预测模型中的指标为:(1)(T11+T12)/2<-8.5℃;(2)(T3+T4)/2>-1.5℃;(3)(T5+T6)>7.5℃;(4)(R5+R6)<48mm。当模型中有3个或4个指标满足,则当年可能发生严重蝗虫灾害,当没有或只有1~2个指标满足,则不会发生严重蝗虫灾害。  相似文献   
62.
研究表明,台湾75毛豆病毒病主要由蚜虫传毒而致,其发生与蚜虫的成虫迁飞时间与发生量关系极为密切.若成虫高峰正遇毛豆1、2叶展平期,毛豆上落蚜量大,发生就重.所以早播的重于迟播的,露地栽培重于套播的.防治上应以栽培避蚜为主,药剂防治为辅,才可取得理想效果.  相似文献   
63.
山东苹果主要病虫害化学防治技术   总被引:2,自引:1,他引:2  
山东省苹果园害虫优势种群是蚜虫、桃小食心虫、苹小卷、金纹细蛾、害螨等 ;病害主要是斑点落叶病、轮纹病。根据不同病虫害的发生发展规律和烟台农科院多年来的化学防治试验研究 ,明确了不同苹果品种上适用的有效药剂和不同药剂的杀虫 (菌 )谱、用药适期、施药方法 ,制定了相应的防治策略 ,提出了合理用药、交替施药和安全喷药等诸多注意事项  相似文献   
64.
本文探讨了测算水稻病虫为害总损失、虫害损失、病害损失、挽回损失和实际损失等五组数据的田间试验设计和方法,并以此来评估水稻病虫为害损失情况,同时分析造成为害损失的病虫主次。  相似文献   
65.
Newcastle disease (ND) is a highly contagious viral disease of birds particularly domestic poultry. Switzerland is currently declared free from ND; since vaccination is prohibited, the detection of antibodies against ND virus (NDV) results in the destruction of the respective flock (stamping-out policy). However, in 1995 and 1996, antibody-positive flocks were detected and sporadic ND outbreaks even occurred in Switzerland. Therefore, a serosurvey was done to look for evidence of NDV infections in Swiss laying-hen flocks. The survey was designed to provide 95% confidence of detecting at least one seropositive flock if the flock prevalence were 1%. Thirty blood samples from each of 260 commercial laying-hen flocks were collected during 1996 in a central poultry slaughterhouse. Sera were screened for NDV antibodies with a commercial blocking enzyme-linked immunosorbent assay (ELISA). Samples with a questionable or positive test result were retested with the same ELISA. A stochastic computer model was applied to define a cut-off number of test-positive samples to help to differentiate between true- and false-positive flocks and to estimate the true flock prevalence of infection. Four flocks were identified as NDV-seropositive and the NDV true seroprevalence among commercial laying-hen flocks in Switzerland was most likely between 1.35 and 1.55%. This indicates that Swiss laying-hen and parental flocks with more than 150 animals have been in contact with strains of NDV that cause subclinical infection in chicken, because no clinical symptoms have been observed. In this context, computer simulation was a useful technique to interpret survey results.  相似文献   
66.
Radiographic evaluation of uterine enlargement is discussed and illustrated. Normal (pregnancy) and abnormal (pyometra, complications of pregnancy, neoplasma) causes of uterine enlargement are addressed. Special radiographic procedures for uterine evaluation are described.  相似文献   
67.
Abstract Cyclosporin has been increasingly used for the treatment of skin diseases in small animals. Reported uses include the treatment of atopy, cutaneous lupus erythematosus, feline acquired alopecia resembling pseudopelade of humans, pemphigus erythematosus, pemphigus foliaceus, perianal fistulae and sebaceous adenitis. In addition, cyclosporin has been used anecdotally for several other skin diseases. Few side effects have been noted at doses therapeutic for dermatologic diseases. Current suggestions for monitoring, and the value of trough cyclosporin serum concentrations for prediction of toxicity and efficacy are discussed.  相似文献   
68.
宁夏苜蓿病虫害发生现状及防治对策   总被引:33,自引:10,他引:23  
通过2001—2002年的田间调查和室内鉴定,明确了宁夏苜蓿病虫害的发生种类、分布和危害程度。目前,在宁夏苜蓿生产中大面积发生并引起灾害性损失的害虫为蚜虫、蓟马、草地螟、象甲和潘叶蝇,病害为苜蓿褐斑病、霜霉病、白粉病和花叶病,并提出相应的防治对策。  相似文献   
69.
Analysis was made of dsRNA in 37 cultivars and species of Ribes, that were healthy, naturally affected with the virus-like diseases, blackcurrant yellows, blackcurrant infectious variegation, gooseberry veinbanding or blackcurrant reversion, or graft-inoculated with scions from such diseased plants. Various dsRNA species, differing in size (from ca. 2 to 11kbp), number and staining intensity in gels, were detected in some or all assays of all plants, including those held as virus-tested stock. In different plant tissues from individual plants, the dsRNA species were usually similar in size and number but, in some sources, the dsRNA profile from flowers and/or bark differed greatly from the profiles of dsRNA obtained from leaves. No dsRNA species were associated consistently with any of these diseases. A 499kbp cDNA probe was obtained that in Northern blot analysis was specific to a ca. 5kbp dsRNA species present in the blackcurrant cv. Baldwin. It also detected a similarly sized dsRNA species in plants of many other blackcurrant cultivars, but it did not react with a similarly sized dsRNA species in redcurrant and gooseberry tissues. The 156 amino acid sequence encoded by the cDNA was very similar to sequences in the RNA-directed RNA polymerases of virus species in the family Totiviridae, especially Saccharomyces cerevisiae viruses L-1 and L-A. The significance of these findings and the possible origin of these dsRNA species are discussed.  相似文献   
70.
生物技术在畜牧业上的应用研究   总被引:1,自引:0,他引:1  
从生物技术与畜禽品种、动物遗传育种,动物饲料资源开发,动物疫病的预防与诊断几个方面,论述了其在畜牧业中的应用,以期用生物技术来推动我国畜牧业的更快发展。  相似文献   
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