Dynamic Development of Aphelenchoides besseyi on Rice Plant by Artificial Inoculation in the Greenhouse

A study was done on the relationship between Aphelenchoides besseyi and the symptoms of small grains and erect panicles. This is an important rice disease in Jiangsu Province, China. A. besseyi was extracted from small grains and erect panicles and cultured artificially, and then inoculated into bud and leaf sheaths of seedlings of two Oryza sativa cultivars, namely Zhendao 2 and Wuyunjing 7 in a greenhouse. The effect on rice growth, in particular the small grains and erect panicles, was revealed by the extent of the disease, seed expansion stages, nematode load, and nematode mortality. In contrast to healthy seedlings, the height, length, and the numbers of spikelets of unhealthy panicles of Zhendao 2 were decreased by 6.7, 16.4, and 13.5%, respectively. Before anthesis, nematodes were attracted to the leaf sheath and apical meristem, nematode load increased by 40%; after anthesis, nematodes occurred in spikelets principally and the number increased by 90.8%. The percentages of infected seeds and nematode load were highest in plump seeds and lowest in empty seeds. Nematode mortality on grain with normal endosperm was lower than seeds with abnormal endosperm. Results indicated that A. besseyi was the pathogen in rice with the symptoms of small grains and erect panicles. Wuyunjing 7 manifests only the small grains and erect panicles symptoms and not the symptoms of leaf white-tip. These symptoms of small grains and erect panicles are new symptom records for the disease caused by A. besseyi on rice.     

高海拔孵化鸡胚死亡曲线分析

利用2阶段增长曲线模型拟合藏鸡和2种低地鸡及其杂交种蛋在2900m（西藏林芝）和3650m（西藏拉萨）海拔的孵化胚胎死亡曲线，分析海拔高度对不同鸡种胚胎死亡的影响。结果表明该模型适宜拟合鸡蛋高海拔孵化时的胚胎死亡规律，拟合度高。藏鸡是高原适应品种，在2个海拔环境中胚胎死亡率均较低。在2900m海拔孵化时，各品种胚胎第l死亡高峰出现在第2．30～4．05d，第2高峰期出现在第17．20～17．68d．品种间相差不大：但藏鸡的第1高峰期持续时间相时较长，为4．04～9．92d；低地鸡和杂种鸡为2．59～3．93d。海拔从2900m升高到3650m，胚胎死亡率增加33．48％～54．12％；同时藏鸡第2高峰期死亡比例增加7．70％～15．65％；低地鸡第2高峰持续期延长13．7l～15．44d；杂交鸡第1高峰期死亡比例增加了5．55％～7．34％，持续期延长0．15～0．66d。     

不同品种·系统后备绵羊零死亡率模式的效益评价

[目的]获取不同品种、系统后备绵羊在零死亡率模式下的效益评价,为养殖种羊的出售提供数据参考。[方法]选择平均初生重接近的母羔,春羔考力代43只(A)及罗姆尼24只(B对照)各1群与冬羔考力代37只(C)母羔1群,共104只。记录断奶重、月末体重、计算死亡率。到次年4月份,剔除死亡羔羊后分析7月至次年4月经济效益。[结果]A、B、C组死亡率分别为4.65%、12.5%、16.0%。罗姆尼B组与冬羔考力代C组在0.01水平上极显著差异。冬、春羔考力代与罗姆尼对照极显著差异。A组盛草期羔羊体重变异系数比B组高1.66个百分点,同时B组低于C组1.82个百分点。9月、12月、4月体重与前3个月在0.05水平上显著相关;到12月后至4月除与3月显著相关外,其他月份在0.01水平上极显著相关。6月龄出售种羊,春羔考力代平均理论利润高于罗姆尼93.21元/只,高冬羔考力代15.3元/只。12月的理论利润春羔高罗姆尼93.92元,高冬羔23.15元。在零死亡率情况下12月出售与9月出售相比,各组每只平均损失A组219.5元、B组240元、C组258元。[结论]初生重、断奶重、死亡率之间无相关性;在该地区春羔考力代绵羊具有更好的选育优势,9月(6月龄)为种羊最佳出售时机。     

超声波对粘虫的处理效果

以常见害虫粘虫为试验材料,用不同剂量超声波处理成虫,观察处理后期粘虫发育阶段的死亡率和羽化率变化情况。结果表明:随着超声波剂量的增大,粘虫死亡率呈明显上升趋势,羽化率有明显下降趋势,超声波作用生物效应显著,当作用时间为140 s时,成虫死亡率急剧升高,高于50%,当作用时间超过180 s时,几乎没有羽化的粘虫。     

九龙江口鳔亚科两种鱼类生长和死亡参数的估算

基于2010年9月—2013年5月连续33个月份在九龙江口紫泥、岛美、浮宫3个站位流刺网和定置网调查采集的样本,对斑鲦和花鲦的生长和死亡特性进行了初步研究,并利用单位补充量产量模型对斑鲦和花鲦渔业的开发状态进行了评估．结果表明：1）斑鲦的体长分布范围为29．0—190．30删,平均为103．54mm;体重分布范围为0．30～121．20g,平均为19．88g．VonBertalanffy生长参数L∞=204．75nlin,K=0．36,t0=-0．45a,总死亡系数、自然死亡系数和捕捞死亡系数分别为1．14、0．46842和0．67158;渔业生物学参考点F0.1和Fmax分别为0．64752和0．74556．2）花鲦的体长分布范围为42．00—143．00min,平均为89．26mm;体重分布范围为1．00—43．85g,平均为11．32g．其生长参数L∞、K和to分别为152．25mm、0．32和-0．55a,总死亡系数、自然死亡系数和捕捞死亡系数分别为1．54、0．47105和1．06895;渔业生物学参考点F0.1和Fmax;分别为1．16578和1．32132．通过YPR模型分析得出：斑鳔资源处于过度捕捞状态,花鲦资源尚未过度利用．     

短周期桉树无性系苗木低温胁迫试验

本试验共测定了54个短周期桉树无性系在人工气候培养室中的低温胁迫伤害指数和死亡率。结果表明,不同低温处理对无性系伤害差异极其显著;苗木不同培育年份对低温伤害指数的影响明显,但对苗木死亡率的作用不大。苗木在低温胁迫处理后1~3 d内观察评分结果具有相当的稳定性和准确性。由于受测试的不同树种和无性系苗木的低温伤害或致死低温范围窄,而直接影响林分的野外环境温度变化较大,因此外界环境的极低温限制应是制约桉树往偏寒地区扩大种植规模的主要因素。在一定的低温范围内,低温胁迫伤害指数在无性系间存在一定水平的遗传变异,通过选择育种可以适度提高无性系抗低温胁迫能力,而结合耐寒桉树树种选育和改进环境与养分条件应可以获得更好的抗性效益。苗木或林木的生长状态对受低温伤害程度有一定的影响。     

Host Plant-Based Artificial Diets Enhance Development,Survival and Fecundity of the Edible Long-Horned Grasshopper Ruspolia differens (Orthoptera: Tettigoniidae)

Wild swarms of the long-horned grasshoppers Ruspolia differens (Serville) which are widely harvested for consumption and sale in Africa are seasonal and unsustainable, hence the need for innovative ways of artificially producing the insects. We investigated the development, survival, and reproduction of R. differens in the laboratory on diets mixed with host plants [Digitaria gayana Kunth, Cynodon dactylon (L.) and Megathyrsus maximus Jacq (Poales: Poaceae); Ageratum conyzoides L. (Asterales: Asteraceae)] identified from guts of their wild conspecifics with a view to developing a suitable diet for artificial mass rearing of the edible insect. A standard diet comprising ground black soldier fly, Hermetia illucens L. (Diptera: Startiomyidae) larvae, soybean flour, maize flour, vitamin premix, and ground bones was tested for rearing R. differens as a control against the same ingredients incorporated with individual powders of the different host plants. Whereas R. differens developed more slowly in the diet mixed with D. gayana than in the control diet; its development was faster in the diet mixed with C. dactylon. Mortalities of R. differens in host plant-based diets were 42.5–52.5%, far lower than in the control diet with 71% mortality. The insects raised on the diet mixed with M. maximus laid approximately twice more eggs compared to R. differens fecundities from the rest of the diets. However, inclusion of host plants in the diets had no detectable influence on R. differens adult weight and longevity. These findings support inclusion of specific host plants in artificial diets used for mass rearing of R. differens to enhance its survival, development, and fecundity.     

南方集体林区生态公益林阔叶树枯损模型的构建研究

探讨阔叶树林分枯损模型的构建,对于经营管理作为我国南方集林区生态公益林的主要树种的阔叶树林分具有重要意义。利用顺昌县优势树种为阔叶树的1996和2006固定样地资料,构建阔叶树枯损模型。结果表明,模型估测的阔叶树林分枯损总数的估测精度为93.89%。     

草坪常用化学药剂对昆虫病原线虫存活和侵染率的影响

测定了草坪上常用的14种化学药剂对蝼蛄斯氏线、长尾斯氏线虫X-7品系和小卷蛾斯氏线虫All品系存活和侵染率的影响。杀虫剂乙酰甲胺磷在高浓度和推荐浓度下对蝼蛄斯氏线虫、长尾斯氏线虫和小卷蛾斯氏线虫的致死率分别为21％和9．5％，13％和5．5％，5．5％和2％；敌百虫在高浓度和推荐浓度下对蝼蛄斯氏线虫的致死率分别高达94．5％和92．5％，在高浓度下对长尾斯氏线虫的致死率为8％，对小卷蛾斯氏线虫没有明显致死作用；克蛾宝对3种线虫的致死作用均比乙酰甲胺磷和敌百虫低。杀菌剂对3种线虫的存活均无影响。除草剂2，4-D丁酯对3种线虫低浓度和高浓度下致死率分别为2％、6％、3．5％和5％、85．5％、6％。经化学药剂处理24h后的线虫侵染黄粉虫9-11龄幼虫，对线虫存活没有影响或者影响较小的化学药剂对线虫的侵染率都没有明显的影响，但剂型为10％可湿性粉剂的吡虫啉对长尾斯氏线虫，以及高浓度的2，4-D丁酯对小卷蛾斯氏线虫的侵染率有明显抑制作用。