油松赤枯病流行规律研究初报

系统观察表明,油松赤枯病病原菌孢子 ５ 月上、中旬开始飞散,５ 月下旬侵染当年生油松针叶,病害初期症状出现在 ６ 月下旬,病情变化与气象因子、立地条件有一定相关性。病害轻重和分布与林木所处位置有关,病情从重至轻的顺序为：南＞ 北＞ 东＞ 西;山脚＞ 山中＞ 山脊;海拔低＞ 海拔高;纯林＞ 混交林。     

昆嵛山赤松纯林赤枯病特征及与林分因子的关系

【目的】解析和定量评价林分因子对赤松赤枯病发生(发病率和病情指数)的影响,为昆嵛山赤松纯林的营林措施和赤枯病的预防提供理论指导。【方法】在昆嵛山区域选取林龄相对一致(约34年)的赤松纯林为研究对象,调查林分密度、郁闭度、树高、枝下高、胸径和冠幅6个林分因子及赤枯病的发病率和病情指数,采用方差分析、相关性分析和多重比较分析各项林分因子与赤松赤枯病之间的关系,并通过冗余分析得影响赤枯病发生的关键因子。【结果】赤枯病在赤松林中普遍发生,发病样地占调查样地的96.3%。整体上,高密度林( 2 956 ~4 089株·hm -2 )的发病率和病情指数显著高于低密度林(688~1 822株·hm -2 )和中密度林(1 823~2 955株·hm -2 )的发病率和病情指数;疏林(郁闭度<30%)的发病率和病情指数显著低于中疏林(郁闭度30%~70%)和密林(郁闭度> 70%)的发病率和病情指数;在不同的树高、枝下高、冠幅和胸径分组中,发病率和病情指数均随着分组值的增大而减小。相关性分析表明:林分密度对赤枯病发病率和病情指数的影响均达到极显著正相关水平( r =0.761, P < 0.01;r =0.748, P < 0.01);赤枯病的发病率和病情指数也均受到郁闭度的极显著影响( r =0.509, P < 0.01;r =0.442, P < 0.01);二者与树高均呈极显著正相关( r =-0.443, P < 0.01;r =-0.362, P < 0.01);赤枯病的发病率和病情指数均随枝下高的增大而极显著减小( r =-0.460, P < 0.01;r =-0.419, P < 0.01);二者与胸径均呈负相关关系,且相关性极显著( r =-0.425, P < 0.01;r =-0.373, P < 0.01);随着冠幅的增大,林木发病率和病情指数均极显著降低( r =-0.345, P < 0.01;r =-0.381, P < 0.01)。冗余分析证明林分密度和枝下高对赤枯病发生的贡献最大。【结论】松赤枯病在昆嵛山区域发生较普遍但不严重,其发病率和病情指数在不同林分因子分组中均有差异,且均受各林分因子极显著影响。RDA分析证明,林分密度和枝下高对松赤枯病影响最显著,建议对昆嵛山区域赤松纯林赤枯病的防治工作要以重要因子为主要调控对象,进行合理修剪和间伐。     

西双版纳香荚兰根腐病发病规律研究

通过系统观察,香荚兰根腐病周年发生,随种植时间延长而病情累积增高。新增病根发病率增高在高温季节,而在低温干旱季节降低。根腐病发病率＜５０％的调查样方有１９．７％的表现出蔓叶发黄;发病率＞６０％的,则有９０％以上的蔓叶发黄,可以把发病率＜４０％作为该病的控制指标。田间管理好,根系发达,生长良好的园地,病情较轻。离体幼根接种试验表明,根尖和根毛区是病原主要的入侵部位。有１５％的幼根不感病,大多数感病根,病斑扩展到一定程度即停止活动,仅有１２％的根病斑发展到全根死亡。病斑扩展期为２～７ｄ,扩展速度为０．２～８．４ｍｍ／ｄ。     

药肥一体化防治八角炭疽病效果试验

在富宁县八角林内选择生长树势基本一致,叶片感病率较高的林分进行药肥一体化防治八角炭疽病试验,统计观察株和枝条的叶片感病率和病情指数。结果显示:防治后试验点的叶片感病率和病情指数为6.30%和2.22,分别下降了5.68%和2.80,地面落叶明显减少,枝梢和枯梢抽出的叶片展开正常,说明药肥一体化吊袋对八角炭疽病防治效果显著,可以在生产上推广应用。     

景洪玫瑰茄基腐病初步研究

<正> 今年雨季期间(七月),东风、橄榄坝农场和我所的玫瑰茄(Hibiscus Sabdariffa L.)先后发生玫瑰茄基腐病,病。株茎基腐烂,导致整株死亡;因当时雨量充沛,病情发展,病区扩大,造成一定的损失。笔者对上述各地病害作了初步观察,并鉴定了病原,现报告于下。     

散射光、变温处理对香石竹玻璃苗的影响研究

香石林组织培养生产过程中最大的障碍是组培苗的玻璃化，对玻璃苗进行自然散射光和自然变温处理，可以见到病情有一定程度的好转，在短时间内，观察到了病苗在生理上和解剖结构上的显著变化。     

辽东地区油松落针病发生规律的研究

采用野外定点观察、抽样调查和室内实验测定等方法,对辽东地区油松落针病害的发生规律进行了研究,结果显示:油松落针病各个发生阶段症状特点明显,每年5～7月针叶枯黄脱落,8～10月针叶上出现明显的无性和有性子实体,该病原菌的侵染循环周期为1年;油松落针病的发生与坡向关系不明显,与坡位有明显关系,坡下腹发病较重;人工纯林病害的发生程度最重,人工混交林和天然混交林的发病程度较轻;林分密度越大发病越重,郁闭度越大发生越重;土壤中有机质、速效氮、速效磷含量随着病情加重而减少,其中速效氮表现最明显;全氮、全磷、速效钾的含量与病害发生关系不紧密.     

花椒黑胫病经济阈值及测报因子的初步研究

在椒园内设样地进行分级调查,测定不同病级花椒黑胫病所对应的产量损失,建立了感病指数与产量损失率之间的线性回归方程Y=0.796 8+0.98x(R2=0.999 9)。依据回归方程及花椒生产实际情况,确定出花椒黑胫病的经济阈值为病情指数5.62,成灾水平因子为病情指数29.80;绝收水平因子为病情指数80.82。     

2009年滇东南植胶区橡胶树棒孢霉落叶病发生情况分析

报道了2009年滇东南植胶区橡胶树棒孢霉落叶病发生情况,分析了河口地区气温和降雨对病情的影响,提出降雨促进病情发展,而干旱的气候条件对病情有一定的抑制作用。     

牡丹一种新病害观察与分析

报道了一种不经意中观察到的牡丹病害。从牡丹异常花蕾观察分析,确定为花蕾畸形现象,进而显微观察分析,确定畸形花蕾为病原虫寄生所致,总结确定为一种新病害,危害花枝,导致蕾期花蕊出露,花瓣残缺,严重削弱牡丹观赏价值,并拟定病名为牡丹葵蕾病。描述了牡丹葵蕾病宏观及显微观察特征,并进行了简单病情调查。     

海南东部垦区部分农场橡胶树叶片营养元素含量分析

对海南省东部部分农场PR107和RRIM600不同产量水平的成龄胶园叶片养分分别进行了研究,结果表明,两个品种的高、中、低产胶园叶片养分状况都存有明显差异,PR107品种高产胶园的全氮和全磷显著高于中、低产胶园;RRIM600不同产量水平的胶园中全钾和钙存在显著差异。高产胶园中,PR107和RRIM600品种间叶片养分含量存在显著差异,因此,要因树施肥,合理配比,达到增产的目的。     

A photographic gap fraction method for estimating leaf area of isolated trees: Assessment with 3D digitized plants

A method for computing leaf area of isolated trees from perspective photographs was developed. The method is based on gap fraction inversion. Photographs are discretized into picture zones where gap fraction is computed from image processing. Canopy volume and leaf area density associated with each picture zone are computed from geometrical considerations and inversion of gap fraction equations. Total leaf area and the vertical profile of leaf area are computed from the product of associated volume and its density. The method has been implemented in software called Tree Analyser, written in C++. The method has been tested by comparison with direct estimation of leaf area of three-dimensional (3D) digitized trees of walnut, peach, mango, olive and rubber. Estimated leaf area was sensitive to picture discretization, individual leaf size and leaf inclination distribution. Optimal size of picture discretization was 17 times projected leaf size. Total leaf area was estimated by using a set of eight photographs taken around the tree in the main horizontal directions: deviation ranged from -11% in peach tree to +5% in rubber tree. The method allows fast and nondestructive monitoring of leaf area of individual tree canopies. The next version of the method will include the estimation of 3D leaf area distribution within the canopy.     

三种热雾剂对橡胶树炭疽病大田防治试验

田间试验比较10%百菌清、20%氟硅唑·咪鲜胺、16%百菌清·咪鲜胺·三唑酮三种热雾剂对大田橡胶树炭疽病的防治试验结果,其中前两种处理防效(相对防效68.14%和66.31%)显著优于16%百菌清·咪鲜胺·三唑酮和对照处理。     

橡胶树棒孢霉落叶病与炭疽病苗圃同防药剂筛选

4种农药对橡胶树棒孢霉落叶病和炭疽病的苗圃防效试验结果:参试农药对棒孢霉落叶病和炭疽病都有不同程度的防效,其中以百菌清最好,防效分别达到80.05%和74.12%,显著高于其它农药处理。     

2008年滇东南植胶区橡胶树棒孢霉落叶病调查报告

2008年通过对云南河口及滇东南植胶区橡胶树棒孢霉落叶病的定点观察和分期调查,结果表明:病害在以较快的速度蔓延、发展;同时对病害与橡胶树物候、气候条件、品种、树龄和立地环境的关系进行初步分析,提出了防治意见。     

Molecular identification of the powdery mildew fungus infecting rubber trees in China

Powdery mildew is a foliar disease of rubber trees. It is one of the most important leaf diseases in rubber plantations worldwide. The causal agent of this powdery mildew, previously known as Oidium heveae, has been identified under various names. To precisely identify the causal agents of this disease, 57 conidial samples were collected from 2013 to 2017 in Hainan, Yunnan and Guangdong provinces, the main rubber tree planting regions in China. Based on morphological observations using light and scanning electron microscopy, pathogenicity testing, and nrDNA ITS and 28S sequences, Erysiphe quercicola is suggested as the only causal agent of rubber tree powdery mildew in China.     

叶柄电导法鉴定橡胶无性系抗寒力的初步研究

橡胶叶柄切段比叶圆片更适于作电导法材料。0℃/45h低温强度能鉴定出品系抗寒力差异。电解质渗出率、伤害率及相对抗性指标适用于橡胶无性系抗寒性测定。     

茎点霉引起的橡胶幼树叶片病害的初步研究

报道西双版纳由茎点霉引起的一种橡胶幼树林叶片病害,及该病害病原菌的鉴定、防治药剂筛选的初步研究结果。     

Active root distribution pattern of <Emphasis Type="Italic">Hevea brasiliensis</Emphasis> determined by radioassay of latex serum

The active root distribution pattern of mature rubber (Hevea brasiliensis Muell. Arg.) up to a lateral distance of 250 cm from the tree and to a soil depth of 90 cm was studied in an oxisol by employing ³²P soil injection technique in Kerala, the state which accounts for 83% of rubber cultivation in India. The trees were aged 18 years and grown at a spacing of 4.9 × 4.9 m. The extent of absorption of applied ³²P by the tree from various placements was assessed by radio assay of leaf and latex serum. Latex serum registered higher counts and variability was less compared to leaf indicating the suitability of latex serum as a potential source for radio assay for ³²P studies in rubber. The results revealed that rubber is a surface feeder with 55% of the root activity confining to the top 10 cm of soil layer. Root activity declined with increasing depths and the concentration of physiologically active roots at 90 cm depth was only 6%. A more or less uniform distribution of root activity was noticed with respect to lateral distance indicating more extensive spread of lateral roots. Concentration of physiologically active roots in the surface layer suggests the possibility for competition under intercropped situation in mature plantations.