新研究发现梨树疫病菌治疗方法-凯发k8官网

新研究发现梨树疫病菌治疗方法
文章来源:未知 文章作者:enread 发布时间:2010-12-29 02:23 字体: [ ] 
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diseases caused by a species of 1 called phytophthora(疫病菌) syringae are responsible for significant economic losses on a wide range of plants, including pear. in the pacific northwest region of the united states, disease occurs during the winter in nursery stock, especially on trees that are harvested and stored in coolers or in outdoor sawdust(锯屑) beds. recent field observations by growers suggest that increased nitrogen content in nursery trees resulting from foliar(叶的) sprays with urea in the autumn increases tree susceptibility to infection by phytophthora syringae. the results of new research suggest the relationship between tree susceptibility to p. syringae and tree nitrogen concentration may be specific to the form of nitrogen, delivery method, or 2 of nitrogen applications. researchers from oregon state university's department of horticulture and the usda-agricultural research service published a study in horttechnology that contains new answers for nursery operators. the experiments investigated the effects of soil nitrogen (n) availability and spraying pear trees with combinations of urea, chelated 3 ethylenediaminetetraacetic acid (cuedta), and phosphonate-containing fungicides on stem n concentration and susceptibility to infection by p. syringae.

experimental results showed that spraying trees with urea in the autumn increased concentrations of nitrogen and amino acids in stems and had no significant effect on tree susceptibility when stems were 4 with p. syringae before or after urea sprays. spraying with cuedta decreased stem nitrogen concentrations and had no significant influence on tree susceptibility to p. syringae when stems were inoculated before or after cuedta sprays, while spraying with fungicides containing fosetyl-aluminum in october or november decreased tree susceptibility to p. syringae. the effects of fungicides containing fosetyl-aluminum on susceptibility were similar regardless of whether trees were sprayed or not with urea or cuedta. according to the report, the results suggest that these fungicides can be used in combination with urea or cuedta sprays for reducing disease severity caused by p. syringae without impacting growers' objective of increasing tree n content with urea or enhancing early defoliation(落叶) with cuedta.

the authors concluded that spraying trees with a combination of urea and cuedta with phosphonate(磷酸酯) - containing fungicides in early autumn can be of benefit for early harvesting and preventing the contamination and/or infection of p. syringae in the field or storage. "spraying pear trees with a combination of urea and cuedta after terminal buds have set in early autumn can benefit nursery operators because the pathogen is less active in warm dry environments and the trees are better able to heal wounds caused by defoliation or chemical treatments", they 5.



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1 gzryi     
n.真菌,真菌类植物
参考例句:
  • mushrooms are a type of fungus.蘑菇是一种真菌。
  • this fungus can just be detected by the unaided eye.这种真菌只用肉眼就能检查出。
2 rguzgc     
n.时间安排,时间选择
参考例句:
  • the timing of the meeting is not convenient.会议的时间安排不合适。
  • the timing of our statement is very opportune.我们发表声明选择的时机很恰当。
3 hzxyu     
n.铜;铜币;铜器;adj.铜(制)的;(紫)铜色的
参考例句:
  • the students are asked to prove the purity of copper.要求学生们检验铜的纯度。
  • copper is a good medium for the conduction of heat and electricity.铜是热和电的良导体。
4 6f20d8c4f94d9061a1b3ff05ba9dcd4a     
v.给…做预防注射( inoculate的过去式和过去分词 )
参考例句:
  • a pedigree pup should have been inoculated against serious diseases before it's sold. 纯种狗应该在出售前注射预防严重疾病的针。 来自《简明英汉词典》
  • disease can be spread by dirty tools, insects, inoculated soil. 疾病也能由不干净的工具,昆虫,接种的土壤传播。 来自辞典例句
5 5n4zxc     
adj.著名的,知名的
参考例句:
  • the local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
  • jim is noted for arriving late for work.吉姆上班迟到出了名。
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tag标签: species fungus
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