河西走廊荒漠草地阔胫萤叶甲生活习性及危害

通过对阔胫萤叶甲Pallasiola absinthii害虫生活习性及危害的研究,发现在甘肃河西半荒漠草原上,阔胫萤叶甲1年发生1代,以卵在草丛基部土层中越冬,主要以驴驴蒿Artemisia dalailamae为食,幼虫期是其主要危害期.阔胫萤叶甲的幼虫具有极强的耐饥饿能力,在不食状态下能存活27d之久;水淹3h后仍能复活;不耐冻,在幼虫孵化出土后遇霜冻气候,对其发生蔓延有抑制作用.适于防治阔胫萤叶甲虫害的农药是4.5%氯氰菊脂和水胺硫磷,其最佳施药量为900和750mL/hm2.     

甲维盐等不同药剂对白刺萤叶甲的药剂防治效果

通过对甲维盐等不同药剂防治白刺萤叶甲的效果进行药剂防治试验,筛选出防治白刺萤叶甲的有效药剂。     

寄主植物对沙葱萤叶甲幼虫生长发育及取食的影响

沙葱萤叶甲（Galerucadaurica Joannis）为近年来严重危害内蒙古草原的重要害虫,为揭示其成灾机制,在室内测定了13种内蒙古草原常见牧草对沙葱萤叶甲幼虫生长发育、存活和取食的影响。结果表明：沙葱萤叶甲幼虫食性窄,主要取食沙葱（Allium mongolium）、野韭（A.ramosum）及多根葱（A.polyrhizum）等百合科葱属植物,其他供试植物基本无取食现象。沙葱、野韭及多根葱对沙葱萤叶甲幼虫期、蛹期和取食量有显著影响,而对其存活率影响不显著。幼虫取食沙葱、野韭和多根葱时,幼虫期和蛹期分别为24.27,27.87,33.13d和6.61,7.40,8.43d,取食量分别为393.76,442.51和496.09mg（鲜重）,3龄幼虫食量最大,占幼虫期总食量的63.45%~67.46%,约为2龄幼虫的3倍、1龄幼虫的5倍。因此,沙葱是沙葱萤叶甲幼虫的最适寄主植物,其次为野韭,然后是多根葱;化学防治时,应在幼虫3龄以前进行。     

短稳杆菌悬浮剂对草原毛虫的防治效果

草原毛虫是四川草原上主要的害虫之一。施用100亿活孢子/毫升短稳杆菌悬浮剂300、450、600 ml/hm~23个处理浓度,对草原毛虫进行防治试验,结果表明:该产品对人、畜安全,不危害草原毛虫天敌,不产生牧草药害;施药14d后,3个处理浓度校正防效分别为78.16%、93.96%和95.46%,综合考虑药效显著性、经济、适用等因素,建议在实际应用中采用450ml/hm~2剂量进行防治。     

荒漠草地白刺粗角叶甲非典型气味受体基因克隆及组织表达谱

白刺粗角叶甲是我国西北荒漠草原危害防风固沙先锋植物白刺的重要害虫之一,开发和利用基于性信息素或寄主挥发物介导的昆虫化学通讯手段是防治该害虫的新途径。本研究以白刺粗角叶甲为对象,通过分子克隆技术获得白刺粗角叶甲成虫触角的非典型气味受体（atypical odorant receptor co-receptor,Orco）基因序列;利用同源建模方法预测蛋白三级结构,并构建系统发育树;借助荧光定量PCR技术检测DrybOrco基因在叶甲成虫各组织中的表达量差异。结果显示：克隆获得的白刺粗角叶甲非典型气味受体基因DrybOrco的cDNA全长为1918 bp,其中开放阅读框为1440 bp,编码479个氨基酸,蛋白分子量为53.94 kD,含有7个跨膜结构域,为疏水性膜蛋白。系统发育表明,Orco基因在6目68种昆虫间保守性较高（相似度大于68%）,聚类分为3个分支,相同目的昆虫聚集到同一支。白刺粗角叶甲与其他鞘翅目昆虫聚为一支,其中与玉米根萤叶甲的Orco基因亲缘关系最近,核酸相似度高达92.28%。荧光定量表明,白刺粗角叶甲DrybOrco基因在成虫触角中特异性表达,且雄虫显著高于雌虫,表...     

新疆北部蒿属荒漠草地叶甲的发生与防治

报导了新疆蒿属荒漠草地优势种叶甲的种类、分布和为害程度，分析了蒿属荒漠草叶甲成灾的原因以及阿尔泰叶甲、脊萤叶甲的咱群消长く态。根据田间药效试验结果，可用１０％氯氰菊酯乳油或４０％氧化乐果同防治阿尔泰叶甲，用２．５％敌杀死乳油防治脊萤叶甲，用４０％氧化乐果乳油防治乌鲁木叶甲。     

新疆草原脊萤叶甲幼虫空间分布型及抽样技术的研究

研究了新疆荒漠草地害虫脊萤叶甲（Theonesilphoides）幼虫的空间分布型及抽样技术,通过频次分布和聚集度指数的测定以及m＊-m回归和Taylor幂法则分析。结果表明,脊萤叶甲幼虫为聚集型中的负二项分布。m＊-m回归分析表明脊萤叶甲幼虫空间分布的基本成分是个体群,幼虫个体间相互吸引,个体群呈聚集分布。Taylor幂法则分析结果表明,脊萤叶甲幼虫个体的空间分布格局随着虫口密度的升高,其聚集程度增强。通过m＊-m回归检验方程确定脊萤叶甲幼虫最适抽样数为440株,仅为实际抽样数的44%。5种抽样方法中,以Z字形法最好,平行线法次之。     

印楝素对荒漠草地蝗虫的防治效果试验

印楝素(Azadirachtin AZ)是从印楝树的种子中提取的一类高度氧化的柠檬素.是一种新型植物源杀虫剂.试验设0.3%印楝素750 ml/hm2、900 ml/hm2、1 050 ml/hm23个试验处理和4.5%氯氰菊酯450 ml/hm2、600 ml/hm2、750 ml/hm23个对照处理.试验结果表明:0.3%印楝素3个浓度对防治草原蝗虫均具有良好的防治效果,其中:900 ml/hm2和1 050ml/hm2浓度水平与对照药品氯氰菊酯的中等浓度水平(600ml/hm2)的防治效果无显著差异.因印楝素杀虫广谱,作用机制特殊,杀虫机理多样,对环境、人畜安全,在防治草原蝗虫时可选择使用.     

60%毒死蜱EC防效及对家蚕的毒性试验

试验结果表明：60％毒死蜱1000倍对鳞翅目害虫的总体防效与甲胺磷2000倍接近,在防治桑尺蠖为主时,毒死蜱浓度以1000倍为宜,防治其它鳞翅目害虫为主时,毒死蜱浓度可选用2000倍,对控制鳞翅目害虫效果较好。安全间隔时间应掌握1000倍20～22天以上,2000倍18～20天以上。     

65%毒死蜱EC田间鳞翅目桑虫防效试验

65%毒死蜱1000倍对鳞翅目害虫的总体防效与20%亚胺硫磷2000倍差异显著,尤其对低龄桑尺蠖的防效。各处理对桑螟等其它害虫的防效比较理想。即在防治桑尺蠖为主时,毒死蜱浓度以1000倍为宜,防治其它鳞翅目害虫为主时,毒死蜱浓度可选用2000倍。     

我国草原虫害生物防治技术应用现状

为了让更多的人了解我国草原虫害生物防治技术应用情况,在查阅文献的基础上,结合我国草原虫害防控工作现状,回顾了草原虫害生物防治工作的进展历程,详细介绍了在推广工作中蝗虫微孢子虫、绿僵菌、类产碱假单胞菌、核型多角体病毒、阿维菌素、牧鸡牧鸭和人工招引粉红椋鸟、印楝素、苦参碱、烟碱·苦参碱等生物药剂和天敌控制技术的研究进展及在草原上的应用现状。最后,总结了近10年我国草原虫害生物防治技术的应用情况,指出我国草原虫害生物防控正在形成由微生物农药、农用抗生素、天敌利用、植物源农药等多种技术构成的新型格局,并针对防治工作中存在的主要问题,提出了对策建议,为今后开展相关研究和工作提供技术支持和参考依据。     

几种杀螨剂防治红花酢浆草岩螨田间试验

几种杀螨剂及其混剂对红花酢浆草岩螨进行田间防治试验,结果表明,单剂20%三氯杀螨醇800~1 000倍防治效果为96%以上;40%氧化乐果、80%敌敌畏防治效果较差。20%螨死净2 000~4 000倍与15%哒螨灵1 500~3 500倍、1%阿维虫清5 000~7 000倍分别混用对红花酢浆草岩螨防治效果为96%以上,但对卵或若螨防治效果差。     

3种植物源农药对蓝莓蚜虫的室内毒力测定及田间防效

[目的] 通过室内毒力测定及田间药效试验评定3种植物源农药对蓝莓蚜虫的防治效果。[方法] 分别采用浸叶法和常规喷雾法进行室内毒力测定和田间药效试验。[结果] 室内毒力测定结果表明3种植物源农药中以0.3%印楝素乳油对蓝莓蚜虫毒力最高,药后48h的LC50值为11.20mg.L-1,3种供试植物源农药相对于22%氟啶虫胺腈的毒力指数均小于1,说明3种植物源农药的毒力显著低于22%氟啶虫胺腈的毒力。田间药效试验结果表明3种植物源农药在各供试浓度下防治效果随药后天数增加而增加,但其防治效果均显著低于22%氟啶虫胺腈的处理,单就3种植物源农药看,苦参碱对蚜虫防效最佳,在药后5d,苦参碱不同浓度防效均在71.64%以上,0.3%印楝素次之,而鱼藤酮对蓝莓蚜虫的防效较差。[结论] 在进行有机生产或蚜虫虫口密度低且对环境安全有较高要求时,蓝莓生产中可以选择苦参碱来降低蚜虫种群基数。     

桑螟食叶量测定及其防治指标的研究

通过对桑螟食叶量测定和发育历期的调查 ,明确了桑螟在 2 5℃恒温条件下的幼虫历期为 12～ 13d ,幼虫一生鲜叶食下量为 4 15mg ,其中 4、5龄的食叶量约占全龄食叶量的 82 3% ,据此可确定桑螟的防治指标和防治适期。经测算 ,桑螟春夏季的防治指标为 2 4 0 0 0～ 30 0 0 0头 /hm2 ,秋季的防治指标为 36 0 0 0～ 6 0 0 0 0头 /hm2 ;而农药防治的最佳时期应掌握在 3龄卷叶前为宜。     

The effect of two pre-cryopreservation single layer colloidal centrifugation protocols in combination with different freezing extenders on the fragmentation dynamics of thawed equine sperm DNA

Background

Variability among stallions in terms of semen cryopreservation quality renders it difficult to arrive at a standardized cryopreservation method. Different extenders and processing techniques (such us colloidal centrifugation) are used in order to optimize post-thaw sperm quality. Sperm chromatin integrity analysis is an effective tool for assessing such quality. The aim of the present study was to compare the effect of two single layer colloidal centrifugation protocols (prior to cryopreservation) in combination with three commercial freezing extenders on the post-thaw chromatin integrity of equine sperm samples at different post-thaw incubation (37°C) times (i.e., their DNA fragmentation dynamics).

Results

Post-thaw DNA fragmentation levels in semen samples subjected to either of the colloidal centrifugation protocols were significantly lower (p<0.05) immediately after thawing and after 4 h of incubation at 37°C compared to samples that underwent standard (control) centrifugation. The use of InraFreeze® extender was associated with significantly less DNA fragmentation than the use of Botu-Crio® extender at 6 h of incubation, and than the use of either Botu-Crio® or Gent® extender at 24 h of incubation (p<0.05).

Conclusions

These results suggest that single layer colloidal centrifugation performed with extended or raw semen prior to cryopreservation reduces DNA fragmentation during the first four hours after thawing. Further studies are needed to determine the influence of freezing extenders on equine sperm DNA fragmentation dynamics.     

24%辛硫磷溴虫腈EC对鳞翅目害虫防效及残毒试验

24%辛硫磷溴虫腈EC(21%辛硫磷+3%溴虫腈)750倍和1500倍对低龄桑螟、桑尺蠖有较好的防治效果。750倍叶面喷雾5d对家蚕安全,可以在蚕期中使用。     

岷江上游山地牧道对林下草本群落分布特征的影响

以岷江上游干旱河谷/山地森林交错带的林下草本层植物群落为研究对象,以牧道为切入点,通过跟踪放牧和样方调查,应用关联和典范对应分析方法探讨山地牧道与草本层群落分布特征的关系。结果表明,牧道样地草本层中耐践踏的菊科占绝对优势,禾本科和豆科植物较少,说明长期放牧下草本层植被有退化趋势。通过9个优势种种间关联分析发现,野艾蒿和老芒麦代表了人工林样地群落特征,黄花蒿、紫苜蓿等其他7种优势种代表了灌丛样地特征,各优势种均表现出环境适应的趋同性和彼此的相似性。牧道分割增加了草本层植物群落分布的异质性,牧道格局指数与草地质量指数基本呈负相关变化规律,而牧道密度与草地质量指数之间的相关性不明显,牧道密度和牧道格局具有一定的指示草地退化的作用,但相互关系复杂。通过CCA排序可知,乔灌层盖度是影响草本层植物分布的最重要因素,其次为牧道密度,坡度和坡位对其分布也有一定的影响。     

观赏草坪斜纹夜蛾化学防治研究

选用8种药剂对观赏草坪斜纹夜蛾进行化学防治研究,并运用方差分析和新复极差(LSR)测验对试验数据进行分析。结果表明:生物农药BT及新型农药克蛾宝对该害虫有较为理想的防治效果,氧化乐果对该害虫有较好的防治效果。在虫口基数不大时可选用BT进行防治,在虫口基数大或高龄幼虫较多时应选用克蛾宝、氧化乐果进行防治,并正确进行药剂的交替使用,以延缓其产生抗药性。     

Nutritional value of mixed grass haylage in Icelandic horses

The influence of cutting time of mixed grass haylages on energy and nitrogen (N) metabolism, and the coefficients of total tract apparent digestibility (CTTAD) were studied in four mature Icelandic geldings by performing total collection of faeces and urine. The experiment was arranged as 4 × 4 balanced Latin square. The four haylages used were harvested at different times and were considered to be representative in botanical composition for mixed grass haylages in Iceland.     

Diet selection by steers using microhistological and stable carbon isotope ratio analyses.

Two methods of determining diet botanical composition, microhistological (MH), and stable carbon isotope ratio (CR) analyses were used to determine botanical composition of ingesta and fecal grab samples in steers grazing rhizoma peanut-mixed tropical grass pastures. Three pastures were used over two grazing seasons, 1992 and 1993, in Brooksville, FL. A weighted-disc double-sampling technique was used to determine forage mass and botanical composition, percentage of rhizoma peanut (Arachis glabrata), grass (Paspalum notatum and Cynodon dactlyon), and forb (primarily Chenopodium ambrosioides) on offer every 28 d throughout the grazing seasons. There was an effect of sampling date (P<.001), sampling date x pasture (P<.001), and sampling date x year (P<.001) on forage mass on offer. There was a pasture x year x sampling date interaction (P<.001) for all botanical components. In 1992 and 1993, using cannulated steers sampled every 56 d, there were interactions with year for rhizoma peanut and forb (P<.05), but not for grass with MH analysis (components: rhizoma peanut, grass, and forb). Ingesta and fecal rhizoma peanut (r = .73 and .92 for 1992 and 1993, respectively) and ingesta and fecal forb (r = .86 and .98 for 1992 and 1993, respectively) were positively correlated (P<.001). Ingesta and fecal grass were positively correlated (r = .52, P<.001), but the correlation was not as high. With the CR analysis (components: Calvin cycle [C3] plants and C4-dicarboxylic acid pathway [C4] plants), ingesta and corrected fecal (corrected for in vitro organic matter digestibility [IVOMD]) C3 plants were positively correlated (r = .62; P<.001). Diet composition of fecal grab samples from noncannulated steers, collected on the same sampling schedule as for hand-clipped pasture samples, differed at times due to the complexity of the sward (both rhizoma peanut and forb constituted a single component, C3, in the CR analysis). Based on these results, if there is a substantial contribution of forb to the diet, fecal microhistological analysis may be more informative than fecal carbon ratio analysis for estimating diet selection by cattle grazing tropical pastures.