麦田恶性杂草节节麦在中国的发生发展   总被引：8，自引：0，他引：8  

房锋  高兴祥  魏守辉  李燕  李美  张朝贤 《草业学报》2015,24(2):194-201

节节麦是世界恶性杂草,目前在我国冬小麦部分种植区成为危害最重的杂草之一,发生面积正在迅速扩大,给我国小麦生产和贸易带来严重影响,造成巨大经济损失。本文结合多年实地调查研究,从命名、分类、形态特征、分布与传播、生物生态学、育种应用、危害影响和防除等8个方面对节节麦进行了综述。  相似文献   

The critical period for weed control in dry-seeded rice     

《Crop Protection》2014

The critical crop-weed competition period in a dry-seeded rice system is an important consideration in formulating weed management strategies. Field experiments were conducted in the summer seasons of 2012 and 2013 at the Punjab Agricultural University, Ludhiana, India, to determine the extent of yield loss in two different rice cultivars (PR 114 and PR 115) with different periods of weed interference. Twelve weed control timings were used to identify critical periods of weed competition in dry-seeded rice. PR 114, a long-duration rice cultivar (145 d) having slower initial growth than PR 115 (125 d), was more prone to yield losses. In both years, 100% yield loss was observed where weeds were not controlled throughout the season. In weed-free plots, the grain yield of PR 114 was 6.39–6.80 t ha⁻¹, for PR 115, it was 6.49–6.87 t ha⁻¹. Gompertz and logistic equations fitted to yield data in response to increasing periods of weed control and weed interference showed that, PR 114 had longer critical periods than PR 115. Critical weed-free periods to achieve 95% of weed-free yield for PR 114 was longer than for PR 115 by 31 days in 2012 and 26 days in 2013. Weed infestation also influenced the duration of critical periods. Higher weed pressure in 2012 than in 2013 increased the duration of the critical period of crop-weed competition in that year. The identification of critical crop-weed competition periods for different cultivars will facilitate improved decision-making regarding the timing of weed control and the adoption of cultivars having high weed-suppressing abilities. This will also contribute to the development of integrated weed management in dry-seeded rice systems.  相似文献   

紫茎泽兰对棉花生长的影响及经济阈值   总被引：2，自引：0，他引：2  

曹坳程  朱文达  颜冬冬  李林 《植物保护学报》2013,40(2):171-176

为明确紫茎泽兰Eupatorium adenophorum Spreng在棉田中的经济危害允许水平和经济阈值,采用添加系列试验和模型拟合的方法,在田间条件下研究紫茎泽兰不同密度对棉花的生长性状及产量的影响.在紫茎泽兰的竞争干扰下,棉花果枝数和单株铃数均随着紫茎泽兰密度的增加而逐渐降低.当紫茎泽兰密度达到60株/m2时,棉花果枝数和单株铃数较无紫茎泽兰对照分别减少了22.1％和57.2％,同时棉花皮棉产量损失率也达到57.2％.棉田田间透光率也随紫茎泽兰密度的增加而降低,当紫茎泽兰密度为60株/m2时,其透光率仅为3.5％.幂函数模型y=3.049x1.031能较好地拟合紫茎泽兰密度(x)与棉花产量损失率(y)间的关系.棉田采用人工除草和41％草甘膦异丙胺盐水剂对紫茎泽兰进行防除时,紫茎泽兰的经济危害允许水平分别为8.42％、1.06％,经济阈值则分别为2.68、0.36株/m2.  相似文献   

Impact of Eucalyptus gall wasp,Leptocybe invasa infestation on growth and biomass production of Eucalyptus grandis and E. saligna seedlings in Tanzania     

Revocatus Petro  Seif S. Madoffe  Said Iddi  Wilson A. Mugasha 《国际虫害防治杂志》2013,59(3):220-227

A study was carried out to determine the impact of Leptocybe invasa infestation on growth and biomass production of Eucalyptus grandis W. Hill ex Maiden and E. saligna Smith seedlings in Tanzania. Three- month old seedlings were infested with L. invasa. Twenty two weeks post infestation, heights of infested E. grandis seedlings were reduced by 39.6%, while diameters were reduced by 11.3% compared to uninfested seedlings. On the other hand, the heights of infested E. saligna seedlings were reduced by 38.2% and diameters were reduced 7.7% compared to uninfested seedlings. Dry weight biomass reduction of infested seedlings was significantly higher on stem and leaves than roots and branches of both E. grandis and E. saligna. The impact of L. invasa infestation on growth and biomass production was higher in E. grandis than E. saligna. Prevention and control of L. invasa infestation should be given priority. Similar future trials should examine other commercially grown Eucalyptus species in Tanzania.  相似文献   

成都平原水旱轮作田常见根结线虫调查   总被引：1，自引：0，他引：1  

徐幸  杨芳  王燕平  谢家廉  李跃建  彭云良  姬红丽 《植物保护》2021,47(5):259-265

调查四川省成都平原地区水旱轮作田根结线虫发生情况及种类分布,为水旱轮作田根结线虫的防治提供依据。对成都平原15个县(市、区)28个乡(镇)共159块水旱轮作田的土样进行根结线虫普遍率调查,利用线虫ITS通用引物和8对根结线虫特异性引物对其中检出率高的地区重新采集的土样进行根结线虫种类分子鉴定。结果表明,成都平原水旱轮作田根结线虫平均检出率为40.25%。重新采集的土样共鉴定出5种根结线虫:拟禾谷根结线虫Meloidogyne graminicola、花生根结线虫M. arenaria、南方根结线虫M. incognita、北方根结线虫M. hapla和爪哇根结线虫M. javanica,各线虫的检出率分别为40.91%、34.09%、13.64%、13.64%和2.27%,其中29.55%的样品由2种以上根结线虫混合侵染。拟禾谷根结线虫和花生根结线虫为该地区优势种群。  相似文献   

Presumptive central nervous system cuterebriasis and concurrent protein‐losing nephropathy in a dog     

Vincent J. Thawley VMD  Jantra N. Suran DVM  DACVR  Elise M. Boller DVM  DACVECC 《Journal of Veterinary Emergency and Critical Care》2013,23(3):335-339

  相似文献   

信息量模型在地质灾害灾情评估及险情预测中的应用     

许林艳 《安徽农业科学》2015,(14)

云南山区是我国地质灾害重灾区之一,由于人们对自然资源的过度开发,以及人们认识的局限性和落后性,地质灾害已严重威胁到人民生命财产安全和区域经济发展.该研究选取距断层距离、降雨量、坡度、地层岩性、距公路距离、距河流距离、坡向和地质灾害分布现状等8个指标作为危险性评价因子,选取村直接经济损失和村人口伤亡2个灾情因子,选取村潜在威胁人口和村潜在财产损失及村人口密度和村地均户数两组险情因子,运用信息量法,以思茅区为例,在地质灾害危险性评价的基础上,进行地质灾害灾情及险情预测评估.结果表明:用信息量法进行地质灾害危险性及灾情和险情预测评估具有可行性、可靠性、科学性及快速性,用村直接经济损失和村人口伤亡作为灾情因子与村人口密度和村地均户数作为险情因子的评价结果更具普遍意义,值得推广.  相似文献   

Amino acid composition and chemical evaluation of protein quality of cereals as affected by insect infestation   总被引：2，自引：0，他引：2  

Sudesh Jood  Amin C. Kapoor  Ram Singh 《Plant foods for human nutrition (Dordrecht, Netherlands)》1995,48(2):159-167

A significant decrease in essential amino acids of wheat, maize and sorghum was observed due to grain infestation caused by mixed populations ofTrogoderma granarium Everts andRhizopertha dominica Fabricius (50:50). Non-essential amino acids were also adversely affected. Among the essential amino acids, maximum reduction was found in methionine, isoleucine and lysine in infested wheat, maize and sorghum grains, respectively. Lysine, with lowest chemical score in uninfested and infested grains of three cereals, is the first limiting amino acid. Insect infestation caused significant (p<0.05) reduction in the chemical score of all the essential amino acids, yet did not change the position of first and second limiting amino acids in wheat and sorghum. However, in case of maize, isoleucine became the second limiting amino acid. Infested grains also showed substantial reduction in essential amino acid index, calculated biological value and requirement index.  相似文献   

刍议高校电子阅览室隐性污染     

宋玲 《农业图书情报学刊》2011,23(9):222-224,F0003

读者在电子阅览室接受简捷便利的网络资源的同时，不知不觉也在遭受各种各样的隐性污染，结合本人工作经验就室内空气污染、电磁辐射污染、噪音污染、键盘和鼠标污染等方面进行了分析并提出了隐形污染产生的原因及相应的防范措施。  相似文献   

麦茬水稻旱种田间杂草综合防除研究初报   总被引：6，自引：0，他引：6  

房志勇  王生轩 《华北农学报》1991,(3)

在田间条件下,研究了杂草的发生危害规律及防除关键技术等.初步认为:1.杂草对旱种水稻生长的影响主要表现在降低产量,减少成穗数、结实率、千粒重和穗长;2.杂草累计收获总干重或禾本科杂草干重可作为杂草危害程度的指标;3.禾本科杂草危害较严重,是旱种水稻田的优势草类;4.旱种水稻除草临界期为播种后第25～40天.此外,对杂草发生潜力、除草时期等也进行了讨论.  相似文献