新型杀蜂螨烟剂蜂乐1号的研究     

姜立纲 《华北农学报》1990,5(1):117-123

蜂乐1号烟剂是一种最近研制成功的新型杀蜂螨药剂,其有效成分为溴螨酯.经室内外试验结果,对蜂螨有较强杀伤力,对蜜蜂十分安全.烟剂中的溴螨醋对雅氏大蜂螨的LC_(50)为0.26克/米~3,LC_(95)为2.92克/米~3 对蜜蜂则分别为71.45克/米~3和218.70克/米~3,二者分别相差274.8倍和74.9倍.一平箱蜂群一次用含0.45克有效成分的药,对蜂体上大蜂螨的防除效果平均93%以上.对蜂群每隔5天施药一次,经3次施药后蜂群状况正常.在施药3次后对所取蜜样进行检测,其中溴螨酯的残留量远远低于联合国粮农组织所规定的参考限量.该烟剂适于在蜂箱外施药,比目前国内一般的开箱施药方法提高工效15倍以上,更适用于许多过去不便用药的场合.  相似文献   

A seroepidemiological study on bluetongue virus in dairy cattle in the central valley of California     

I. J. Uhaa  H. P. Riemann  M. C. Thurmond  C. E. Franti 《Veterinary research communications》1990,14(2):99-112

A seroepidemiological study on bluetongue virus (BTV) infection in California dairy cattle was conducted to estimate the prevalence and distribution by age and season of BTV group-reactive antibodies and to look for possible associations between the presence of antibodies and cattle age or breed and farm. Between December 1985 and March 1987, a sample of cattle was tested at approximately two-month intervals for BTV group-reactive antibodies using an enzyme-linked immunosorbent assay (ELISA). Data taken during the month of December 1986 were used to evaluate possible associations between a positive antibody test and certain intrinsic (age, breed) and extrinsic (farm) factors.Univariate and multivariate statistical analyses using the -square test for associations and multiple logistic regression, respectively, were carried out for possible associations between positive antibody tests to BTV and each factor of interest. The strengths of the associations were determined using estimates of the odds ratio.Of the 3774 serum samples tested, 238 (6.3%) were from calves, 1045 (27.6%) were from heifers and 2492 (66.0%) were from cows. Seroprevalence varied from nil in calves on two occasions to over 90% on several occasions in cows. Cows consistently had higher prevalence rates than heifers or calves across all test dates (p<0.05). The seroprevalence of BTV group-reactive antibodies also showed a seasonal fluctuation, with the highest rates occurring during the warmer months of the year. These highest prevalence rates coincided with heavy activity of the known vector of BTV, Culicoides spp. Breed and farm effects were not statistically significant (p>0.05). With the exception of one farm, all cattle were of the Holstein breed, which reduced confidence in assessing any breed effect in this study. Relative estimates of the sensitivity and specificity of BTV ELISA were 87% and 100% respectively, compared to the standard agar gel immunodiffusion (AGID) test.The observations support previous findings of seasonal distribution of BTV antibodies and suggest an age relationship, whereby older cattle are more likely to be positive to BTV group-reactive antibodies than younger cattle.  相似文献   

The effect of some Frescon analogs on the aquatic snail,Lymnaea stagnalis: II. Correlation of neurotoxicity to Molluscicidal effectiveness     

B.L. Brezden  D.R. Gardner 《Pesticide biochemistry and physiology》1980,13(2):178-188

Although the molluscicide Frescon is a strong neurotoxin to the Lymnaea stagnalis central nervous system in vitro, it is probable that the exposure of the whole animal to this molluscicide fails to result in central nervous system abnormalities: Frescon does not appear to reach the brain in sufficient quantity to disrupt its normal activity. However, only those Frescon analogs found to be neurotoxic were molluscicidal, suggesting some related mode, if not site, of action. Frescon and its analogs may act by affecting excitable tissues other than the nervous system (e.g., the snail musculature) by altering certain functional and/or structural membrane properties.  相似文献   

Age-related resistance to Pseudomonas syringae pv. tomato is associated with the transition to flowering in Arabidopsis and is effective against Peronospora parasitica     

C. Rusterucci  Z. Zhao  K. Haines  D. Mellersh  M. Neumann  R.K. Cameron   《Physiological and Molecular Plant Pathology》2005,66(6):120

As plants mature it has been observed that some become more resistant to normally virulent pathogens. The ability to manifest the Age-Related Resistance (ARR) response in Arabidopsis to Pseudomonas syringae pathovars tomato (Pst) coincided with the transition to flowering in plants both delayed and accelerated in the transition to flowering. ARR was also associated with a change in PR-1 gene expression, such that young plants expressed PR-1 abundantly at 3 days post inoculation (dpi) while mature plants expressed much less. The Arabidopsis ARR response requires SA accumulation via isochorismate synthase (ICS1) [24]. ICS1 was expressed one dpi with virulent and avirulent Pst in both young and mature plants. The ARR response was also effective versus avirulent Pst providing an additional 4-fold limitation in bacterial growth. Arabidopsis ARR was found to be ineffective against two necrotrophs, Erwinia carotovora subspecies carotovora (bacterium) and Botrytis cinerea (fungus) and one obligate biotroph, Erysiphe cichoracearum (fungus). However, mature wild type, SA-deficient sid2 and NahG plants supported little growth of the obligate biotrophic oomycete, Peronospora parasitica. Therefore ARR to P. parasitica appears to be SA-independent, however the level of ARR resistance was somewhat reduced in these mutants in some experiments. Thus, there may be numerous defence pathways that contribute to adult plant resistance in Arabidopsis.  相似文献   

早熟春甘蓝新品种春冠的选育     

丁万霞  李建斌 《中国蔬菜》2005,(10):30-31

春冠亲本之一493是将国外引进的资源96011、9502杂交后，经系统选育，采用露地越冬栽培加大耐先期抽薹性的选择强度选育出的自交不亲和系。另一亲本711是从国外引进的资源B-21经多代自交选育出的自交不亲和系。该品种耐寒，露地越冬不易先期抽薹，早熟，叶球尖桃形，肉质脆嫩，品质佳。单球质量1.5kg左右，每667m^2产量3500kg左右。在南方地区可露地越冬栽培，已在长江流域示范推广。  相似文献   

保护地番茄新品种苏粉8号的选育     

赵统敏  余文贵  徐鹤林 《中国蔬菜》2005,(10):37-38

苏粉8号系以GB9736为母本,TM9761为父本配制而成的适合保护地栽培的中熟番茄一代杂种.属无限生长型.果实高圆形,粉红色,果面光滑,果皮厚,耐贮运,品质佳,可溶性固形物含量5.0%,酸甜适中,单果质量200～250 g,产量6 000kg·(667 m2)-1以上.高抗ToMV-0,1株系、叶霉病,抗枯萎病,中抗CMV.已在江苏、山东、四川、浙江等地示范推广逾266.7 hm2.  相似文献   

茄子新品种湘杂早红的选育     

杨建国  姚元干  皮向红 《中国蔬菜》2005,(10):63-64

以南县紫圆茄的自交系92147为母本，陕西汉中紫茄的自交系96267为父本配制成一代杂种湘杂早红。从定植到始收约35d（天），果实紫红色，卵圆形，果肉白色，肉质细嫩，单果质量250g左右。对青枯病和绵疫病的抗性比湘早茄强。每667m^2产量3000—4500kg，适合春栽。  相似文献   

Breeding objectives for beef cattle used in different production systems: 2. Model application to production systems with the Charolais breed     

M. Wolfová  J. Wolf  J. P?ibyl  E. Krupa 《Livestock Production Science》2005,95(3):217-230

A general bio-economic model for beef cattle production was used to define breeding objectives for Charolais cattle to be utilized in a variety of linked production systems. Economic weights were calculated for 16 traits (some with both direct and maternal components) in three production systems (pure-breeding and terminal crossing with beef or dairy cows) and two marketing strategies (sale or fattening of weaned surplus calves). Economic weights for the total breeding objective were calculated as weighted averages, where weights were numbers of cows expected to be mated with Charolais bulls in each production system and marketing strategy. Results suggest that the direct component of calving performance and cow longevity were of primary economic importance in all systems. Conception rate of cows and weaning weight reached about 50% of the standardized economic weight of calving performance in purebred systems with sale of weaned calves, whereas in purebred systems with fattening the economic importance of the direct component of cow conception rate, losses at calving, mature weight of cows, weaning weight, and fattening traits were of equal importance (each approximately about 20% that of calving performance). In terminal crossing systems, weaning weight was important when calves were sold at weaning, and fattening traits were important for systems selling fattened animals. The bio-economic model performed well under the conditions of this demonstration and could easily be customized for other applications.  相似文献   

甜瓜新品种-中甜1号的选育     

徐永阳  徐志红  刘君璞 《果树学报》2005,22(3):300-301,F002

中甜1号为优质、高产、耐湿、早熟厚皮甜瓜品种,果实发育期25-28d,果实椭圆形,果皮黄色,上有10条银白色纵沟,果肉白色,单瓜重1.0-1.5kg,可溶性固形物含量13.5%-15.5%。适应性广,在保护地、露地条件下均可栽培。  相似文献   

西葫芦新品种济葫2号的选育     

李秀启  卢立轩  陈坤  马朝喜  刘星明  黄莎莎 《长江蔬菜》2005,(4):48-49

济葫2号是以QL0133和QLO119配制而成的西葫芦一代杂交种,植株生长旺盛、株型紧凑、矮蔓、早熟、丰产,抗病毒病、白粉病、蔓枯病.瓜浅绿色,嫩瓜长20.0 cm,粗6.0 cm,粗细均匀、品质佳.每667 m2产量达6 500kg,适于早春茬、秋冬茬及越冬茬栽培.  相似文献