高产型徐香猕猴桃树体结构及土壤养分状况分析

为明确猕猴桃果园的生产潜力，在普查的基础上对两个管理水平较高的徐香猕猴桃果园的树体结构及土壤养分状况进行分析。结果表明，高产型徐香猕猴桃树体的合理结构为成龄树冬季修剪后单株保留17个左右结果母枝，每枝保留15~21个有效芽，折合每667 m留长枝量为1 496个，留芽量为22 440~23 760个，7月份叶果比为3.33∶1。土壤速效氮为16.5 mg/kg，速效磷64.8 mg/kg，速效钾209.6 mg/kg，速效镁和速效铁分别156.6 mg/kg和3.58 mg/kg，有机质含量1.13%。可见，充足的肥料投入、枝芽数量及合理的叶果比是高产稳产的基本保证。     

气相色谱法测定水果中咪鲜胺残留量的方法研究

采用丙酮震荡提取样品，在水解衍生的步骤中创造性地使用试管加入吡啶盐酸盐，于220℃的烘箱里水解1.5 h，经过处理后使用气相色谱ECD进行测定。结果表明：该方法的线性范围为0.005～0.500 ng，相关系数为0.999 9；对香蕉、绿橙、花牛苹果、青苹果、猕猴桃、砀山梨6种空白基质分别进行了0.01、0.10、1.00 mg/kg 3个水平加标，其回收率为81.0%～106.4%，相对标准偏差(RSD，n＝5)为0.3%～5.7%；该方法的最低检出限为0.01 mg/kg，并且烘箱水解的新方法操作简便     

果蜡处理对低温贮藏下采后菠萝果实激素的影响

以菠萝品种‘巴厘’的果实为试材，研究果蜡处理对低温贮藏下采后菠萝激素的影响，结果表明：果蜡处理降低了冷藏菠萝果实脱落酸(ABA)、赤霉素(GA)和玉米素(ZR)含量，增加了吲哚乙酸(IAA)含量，并且ABA 和GA含量均与冷害指数极显著相关(P＜0.01)，相关系数分别是0.879和0.909。表明低温胁迫下采后菠萝的ABA和GA与抗冷性密切相关，果蜡处理降低了ABA和GA含量，从而提高菠萝抗冷性。     

Epidemiology and control of Menangle virus in pigs

OBJECTIVE: To describe the epidemiology and eradication of Menangle virus infection in pigs. DESIGN: Field observations and interventions, structured and unstructured serological surveys, prospective and cross-sectional serological studies and laboratory investigations. PROCEDURE: Serum samples were collected from pigs at a 2600-sow intensive piggery in New South Wales that experienced an outbreak of reproductive disease in 1997. Serum samples were also collected from piggeries that received pigs from or supplied pigs to the affected piggery and from other piggeries in Australia. Serum and tissue samples were collected from pigs at piggeries experiencing reproductive disease in New South Wales. Sera and faeces were collected from grey-headed flying foxes (Pteropus poliocephalus) in the region of the affected piggery. Serum samples were tested for neutralising antibodies against Menangle virus. Virus isolation was attempted from faeces. RESULTS: Following the outbreak of reproductive disease, sera from 96% of adult pigs at the affected piggery, including sows that produced affected litters, contained neutralising antibodies against Menangle virus. Neutralising antibodies were also detected in sera from 88% of finisher pigs at two piggeries receiving weaned pigs from the affected piggery. No evidence of Menangle virus infection was found in other piggeries in Australia. In cross-sectional studies at the affected piggery, colostral antibodies were undetectable in most pigs by 14 to 15 weeks of age. By slaughter age or entry to the breeding herd, 95% of pigs developed high antibody titres (> or = 128) against Menangle virus in the virus neutralisation test. Menangle virus was eradicated from the affected piggery following a program of serological testing and segregation. Neutralising antibodies against Menangle virus were also detected in P poliocephalus from two colonies in the vicinity of the affected piggery. Two piggery workers were infected with Menangle virus. There was no evidence of infection in cattle, sheep, birds, rodents, feral cats and a dog at the affected piggery. CONCLUSIONS: Serological evidence of infection with Menangle virus was detected in pigs at a piggery that had experienced reproductive disease, in pigs at two associated piggeries and in fruit bats in the region of the piggery. Two humans were infected. The mode of transmission between pigs is unknown, but spread by faecal or urinary excretion is postulated. This virus can be eradicated by the segregation of pigs into discrete age groups.     

基于分子遗传标记技术的实蝇种群遗传关系研究进展

分子遗传标记技术已用于分析实蝇的种群遗传关系,本文介绍了分子遗传标记技术在实蝇的起源、入侵、定殖、扩散及其他方面的研究进展,首次分析了我国实蝇种群遗传研究的现存问题并针对检疫性实蝇种群遗传关系研究提出了建议.     

Testing variability in pathogenicity ofPhytophthora cactorum, P. citrophthora andP. syringae to apple, pear, peach, cherry and plum rootstocks

The relative virulence ofPhytophthora cactorum andP. syringae originating from almond trees, and ofP. citrophthora originating from citrus, to apple, pear, peach, cherry and plum rootstocks, was studiedin vivo andin vitro. Results of the different experiments were in good agreement. All testedPhytophthora isolates showed little virulence to pear rootstocks-causing only minor crown rot symptoms - and no virulence at all to apple rootstocks. In contrast, they were highly virulent to stone fruit rootstocks, causing crown rot disease. The non-pathogenicity of these isolates to pome rootstocks could be interpreted as strict host specificity.     

A novel method for rearing the progeny of wild mediterranean fruit flies using artificial fruit

A technique for rearing the progeny of wildCeratitis capitata flies was developed. The method is based on wild captured flies which are allowed to oviposit in artificial fruit containing larval rearing medium. Flies develop in the fruit from eggs to last larval instar, then exit the fruit and pupate within vermiculite. This method was shown to be feasible and efficient, and to increase considerably the number of wild flies for testing purposes. Possible contribution to the Sterile Insect Technique (SIT) and potential applications of the method are discussed.     

云南桔小寡鬃实蝇种群动态研究

经过水平和垂直地带的性诱观测与室内外调查试验，发现云南桔小寡鬃实蝇年发生４－５代。第二代为主害代，主要为害芒果、桃、番石榴等。成虫诱集高蜂期除柑桔点（高峰期为９－１０月）、甜橙点（高峰期为１０－１２月）外，蓁各点均在６－７月间。各年高峰期早晚和诱集量不同。同年各点成虫高峰期出现的时间也有差异，主要表现为从南到北高峰期推迟。冬季除昆明外，其它各点均可诱到成虫。以高温高湿的西双版纳数量最多。同一地区随     

芜菁夜蛾线虫在防治桃小食心虫上的应用

应用芜菁夜蛾线虫Ｓｔｅｉｎｅｒｎｅｍａ ｆｅｌｔｉａｅ ａｇｒｏｔｅｓ防治桃小食心虫Ｃａｒｐｏｓｉｎａ ｎｉｐｏｎｅｎｓｉｓ Ｗａｌｓｉｎｇｈａｍ的研究表明，线虫寄生桃小的温湿度范围：温度２０℃－３５℃，土壤含水量７％－１５％，以温度２５－３０℃，含水量１０％左右致死速度最快。此特性与桃小越冬幼虫出土所需求的条件相一致，肯定了应用线虫防治桃小在出土期为宜，线虫的施用量为每ｍ＾２６０－８０万头，持续