陇东旱地果园地表覆盖方式对苹果光合特性的影响

为筛选出适宜陇东旱塬地区苹果园的土壤耕作模式,以20年生苹果树为试材,研究不同地表覆盖方式对苹果叶片光合特性的影响,并从经济效益方面进行比较分析。结果表明：清耕(F4)净光合速率(Pn)日变化为双峰型,地膜覆盖(F1)、麦草覆盖(F2)和覆砂(F3)为单峰型;其中覆草净光合速率最高,10:00达到峰值,并显著提 高水分利用效率(WUE)(P<0.01)。净光合速率(Pn)与大气相对湿度(RH)呈极显著正相关,与气温(Ta)、叶温 (Tl)呈显著负相关;蒸腾速率(Tr)则与Ta与Tl呈显著正相关。覆草后光补偿点(LCP)显著降低,光饱和点(LSP)显著提高,表明对光照的适应范围较宽;并且Pn_max显著高于CK,CO₂补偿点显著低于F1、F3和F4。经济效益分析 表明,覆膜果园的收入与产投比均较高。可见,陇东旱地果园覆草和覆膜均可显著提高富士苹果叶片光合作用,增 强光能与CO₂的利用能力,有利于干物质形成,增加产量。     

胡杨和灰胡杨叶绿素荧光特性对地下水位的生态响应

选取塔里木河上游不同地下水位的样地作为研究点,利用便携式调制叶绿素荧光仪测定了不同地下水位下胡杨、灰胡杨的叶绿素荧光特性和PSⅡ光合活性.结果表明:随地下水位下降,胡杨、灰胡杨表观光合电子传递速率(ETR)、实际光化学量子效率(Φ_PSⅡ)、光化学猝灭系数(_qP)、光化学速率(PCR)、最大荧光(Fm)和PSⅡ潜在光合活性等参数普遍降低；而非光化学猝灭系数(NPQ)、调节性能量耗散量子产量(Y_NPQ)、非调节性能量耗散量子产量(Y_NO)、叶片光合功能相对限制值(PED)和光系统间激发能分配不平衡偏离系数(β/α-1)显著升高,但其最大光化学量子产量(Fv/Fm)总体处于相对适宜状态(＞0.815)。表明两树种PSⅡ光合活性随地下水位下降而降低,光能捕获效率与光化学反应能量下降,耐受强光能力减弱,获取过剩光能程度和PSⅡ受损风险增加。但两树种可通过良好的抗逆性和自我调节机制,增强热耗散来缓解光能过剩带来的损伤,从而使PSⅡ未发生不可逆损伤,保持其较高的光合效率。比较不同地下水位下胡杨和灰胡杨的叶绿素荧光参数发现,胡杨PSⅡ反应中心活性与光化学效率较高、耐旱性较强,表明胡杨对荒漠干旱环境的适应性强于灰胡杨。     

小麦白粉病与温度的定量关系研究

温度对小麦白粉病影响试验的结果表明,此病害适宜发生的温度为15～20℃,低于10℃或高于25℃对该病有明显抑制作用。当温度高于26℃时,试验显示随着温度的升高,终止小麦白粉病病程的时间缩短,据此建立了不同温度(x)与相应终止病程的时间(y)的关系模型为y=21 900e^{-0.303 5x}(χ²=1.65<χ²_0.05,7=14.07)。同时,根据高温区病害的严重度(y)与温度(x)的试验数据,建立了其关系模型为:y=-3.00x+76.60(r²=0.922 1^**),由此计算获得了连续10 d(一个病程时间)温度为25.53℃即可终止此病害的病程。该试验结果将为小麦白粉病的越夏区划提供基础数据。     

五味子茎基腐病发生初报

通过对辽宁省多个地区的调查,发现此病害发生普遍,尤其是二年生的五味子茎基腐病发生严重。五味子茎基腐病在5月上旬开始出现,6月初为发生盛期。本文对五味子茎基腐病进行了症状描述,并对不同地点采集的病样分别进行木质部和韧皮部病原物的分离、纯化。对分离得到的菌株按照柯赫氏法则进行致病性测定并对病原菌进行鉴定,结果表明,此病害可由木贼镰刀菌(Fusarium equiseti)、茄腐镰刀菌(F.solani)、尖孢镰刀菌(F.oxysporum)和半裸镰刀菌(F.semitectum)4种镰刀菌属真菌引起。针对此病害的发生特点,提出了相应的防治措施。     

肾状线虫属重要种类的鉴定和特征描述

记述了目前世界上认可的肾状线虫属(Rotylenchulus sp.)已知的10个种的重要鉴定特征、世界分布和寄主范围。这10个种包括越南肾状线虫(R.anamictus)、短管肾状线虫(R.brevitubulus)、北方贝肾状线虫(R.borea-lis)、短尾肾状线虫(R.clavicaudatus)、离异肾状线虫(R.leptus)、大囊肾状线虫(R.macrodoratus)、长肾状线虫(R.macrosoma)、微小肾状线虫(R.parvus)、肾形肾状线虫(R.reniformis)和甘蔗肾状线虫(R.sacchari)。并对其最具经济意义的两种线虫的特征进行了描述。     

青海省海东地区小麦赤霉病致病菌种及致病性研究

1993～1995年在青海海东地区采集1005个麦类赤霉病标样 ,鉴定结果表明其分别属于镰刀菌属的 7个种 ,其中禾谷镰刀菌(Fusarium graminearum)出现频率为54.3% ,接骨木镰刀菌 (F .sambucinum)出现频率为19.3% ,锐顶镰刀菌(F .acuminatum)、燕麦镰刀菌(F .avenaceum)和黄色镰刀菌(F .culmorum)出现频率均为6.5%,三线镰刀菌(F .tricinctum)和茄病镰刀菌(F .solani)为3.2%。对小麦穗部致病力测定结果 ,禾谷镰刀菌为“强” ,接骨木镰刀菌、茄病镰刀菌为“中-强” ,三线镰刀菌为“弱-中” ,黄色镰刀菌、锐顶镰刀菌和燕麦镰刀菌为“弱”     

昆明市白车轴草上蓟马种群动态调查

对昆明市白车轴草上蓟马种类及其周年种群动态进行了调查。白车轴草上蓟马主要有西花蓟马(Fran-kliniella occidentalis)、丽花蓟马(F.intonsa)、八节黄蓟马(Thrips flavidulus)、端大蓟马(Megalurothrips distalis)、稻单管蓟马(Haplothrips aculeatus)和烟蓟马(T.tabaci),有时会出现黄胸蓟马(T.hawaiiensis)、玉米黄呆蓟马(Anaphothrips obscurus)、苏丹呆蓟马(A.sudanensis)和云南纹蓟马(Aeolothrips yunnanensis)。本文分析了前6种蓟马的周年种群动态,重点阐述了外来有害生物西花蓟马,该虫主要在3~6月发生,是此期间白车轴草上的蓟马优势种。     

我国南方稻区水稻骨干亲本纹枯病抗性鉴定与分析

运用改进的纹枯病菌接种法,对当前我国南方稻区17个骨干亲本纹枯病抗性进行了田间鉴定,测定和分析了各材料的纹枯病病级(R_D)、相对病斑高度(H_R)及株高(H_P)。通过试验,将17个骨干亲本分为抗病、中等抗病、中等感病和感病4种类型;筛选出了3个抗病亲本(明恢63、蜀恢527、广恢128)和3个中抗亲本(绵恢725、珍汕97B和协青早B);供试亲本的平均RD为4.78,平均HR为0.52;通过分析,发现纹枯病病级(R_D)和相对病斑高度(H_R)呈极显著正相关(y=8.373x+0.435,y=RD;x=H_R)、株高和病级相关不显著。     

南京地区夏大豆田蚜虫的消长与大豆花叶病毒(SMV)病的流行

南京地区夏大豆田的定殖蚜虫主要是大豆蚜(Aphis glycines)。1987和1988两年黄皿共诱到29种蚜虫,其中以大豆蚜数量最多,是传播SMV的主要介体,其他介体蚜虫有:绣线菊蚜(A.citricola),豆蚜(A.craccivora)、棉蚜(A.gossypii)、萝卜蚜(Lipaphis erysimi)、桃蚜(Myzus persicae)、玉米蚜(Rhopalosiphum maidis)、麦二叉蚜(Schizaphis graminum)和二叶草彩斑蚜(Therioaphis trifolii)。1987年蚜虫迁飞峰出现在大豆花期以前,2周后田间出现发病高峰,SMV发病增长率与蚜虫迁飞量呈显著的线性正相关(P<0.01);1988年蚜虫迁飞峰发生在大豆花期以后,其迁飞量与SMV的流行无显著线性相关(P>0.05)。     

烟草赤星病危害烤烟产量产值损失测定

在烤烟生长中后期 ,应用40%菌核净500倍液人为控制烟草赤星病发生程度 ,形成不同危害梯度 ,以研究烟草赤星病对产量产值的影响。经试验分析 ,建立数学模型。中上等烟产量损失率(Y₁)与病情指数(X)的关系式:Y₁=0.1516+1.2824X;产值损失率(Y₂)与病情指数(X)的关系式:Y₂=0.3239+0.9831X。     

河北省苹果果实黑点病的症状与病原研究初报

为明确河北省苹果果实黑点病的症状类型及其对应的病原菌,本研究对河北省6个市的果园进行了病害调查和样品采集,并对引起不同症状类型的病果进行了病原菌的分离和鉴定.结果表明,河北省的套袋苹果黑点病可以分为四大类型,分别是萼洼黑点型、果面黑点型、果面晕斑型和梗洼褐斑型.除了果面晕斑型为单一病原侵染之外,其他类型的病斑均分离获得...     

Resistance to common insecticides and mechanisms of resistance in Aphis pomi de Geer (Hemiptera: Aphididae), in apple orchards in Turkey

Phytoparasitica - The Green apple aphid, Aphis pomi de Geer (Hemiptera: Aphididae), is one of the most common and serious insect pests of apple orchards in Turkey. This species feeds on succulent...     

河北省苹果果实黑点病的发病规律及药剂防控研究

 近几年,河北省苹果产区苹果果实黑点病大面积发生。该病害在河北省的流行规律以及时空分布尚不清楚,给病害防控带来挑战。2018年对河北省不同市区的4个果园分别进行黑点病调查,并对其在苹果树上的空间分布以及发生时间进行动态监测,开展田间药剂防效试验。结果表明:苹果果实黑点病在7月中下旬开始出现明显症状,果树中层内膛病果率较高,上层外膛病果率较低;套袋苹果的萼洼处发病率较高,以黑点型症状为主;不套袋苹果的果面发病率较高,以晕斑型症状为主;‘斗南'、‘富士'品种的发病率较高,‘中秋王'、‘乔纳金'品种的发病率较低。田间药剂防效试验表明,50%异菌脲1 500倍液防效最好,防治效果均达54%以上。其次为10%多抗霉素1 000倍液,而80%代森锰锌600倍液、10%吡唑醚菌酯1 500倍液防效较低。研究结果可为河北省苹果果实黑点病的综合防控提供理论支持。     

Phenotypic,molecular and pathogenic characterization of Phlyctema vagabunda,causal agent of olive leprosy

Olive leprosy, caused by the fungus Phlyctema vagabunda, is a classic fruit rot disease widespread in the Mediterranean basin. From 2009 to 2013, new disease symptoms consisting of small circular necrotic leaf lesions, coin branch canker and shoot dieback were observed in Spanish and Portuguese olive orchards showing intense defoliation. Phlyctema‐like anamorphs were consistently isolated from leaves and shoots with symptoms. Representative isolates from affected leaves, shoots and fruits were characterized based on morphology of colonies and conidia, optimum growth temperature and comparison of DNA sequence data from four regions: ITS, tub2, MIT and rpb2. In addition, pathogenicity tests were performed on apple and olive fruits, and on branches and leaves of olive trees. Maximum mycelial growth rate ranged between 0.54 and 0.73 mm per day. Conidia produced on inoculated apple fruits showed slight differences in morphology among the representative fungal isolates evaluated. Phylogenetic analysis clustered all of the Phlyctema‐like isolates in the same clade, identifying them as Phlyctema vagabunda. On fruits, influence of wounding, ripening and cultivar resistance was studied, with cv. Blanqueta being the most susceptible cultivar. On branches, a mycelial‐plug inoculation method reproduced olive leprosy symptoms and caused shoot dieback. On leaves, Koch's postulates were fulfilled and the pathogen caused characteristic necrotic spots and plant defoliation. This is the first time that the pathogenicity of P. vagabunda in olive leaves has been demonstrated.     

Black Spot of Peach Caused by <Emphasis Type="Italic">Alternaria alternata</Emphasis> (Fr.) Keissler

A new disease of peach (Prunus persica Batsch var. vulgaris Maxim.), causing brown, sunken lesions and brownish to blackish brown spots with cracks on peach fruits, was found in Okayama prefecture, Japan, in 1995. The disease was observed not only on peach fruits but also on twigs and leaves. An Alternaria sp. was consistently isolated from these diseased fruits, twigs and leaves. The isolates were pathogenic to peach fruits and leaves. Based on the morphological characteristics, the causal fungus was identified as Alternaria alternata (Fr.) Keissler. After cross-inoculation with isolates from peach, Japanese pear and apple, the isolates were found to be pathogenic only to their original host. This is the first report on a peach disease caused by a host-specific A. alternata; therefore, the common name of black spot (`Kokuhanbyo' in Japanese) was proposed. Received 25 June 1999/ Accepted in revised form 12 October 1999     

新烟碱类杀虫剂在苹果果实不同部位中的残留

为了明确噻虫嗪、烯啶虫胺、吡虫啉、啶虫脒、噻虫胺和呋虫胺6种新烟碱类杀虫剂在苹果果实不同部位中的迁移转化规律,以10年生红富士苹果树为试材,分别于蚜虫发生期 (7月10日) 和果实采收前1 d (9月25日) 通过整株喷雾施药,随机取样,采用高效液相色谱仪测定,外标法定量,分析各杀虫剂在生长期套袋果实和不套袋果实及储藏期果实不同部位中的残留量及迁移规律。结果表明:在果实套袋情况下,施药后72 h内果实不同部位各新烟碱类杀虫剂的含量均呈现先逐渐上升而后下降的趋势,且在果皮中的残留量最低 (均低于0.08 mg/kg),其中烯啶虫胺和吡虫啉在果皮中的残留量低于最低检测浓度,而在果柄和果肉中的残留量明显高于果皮中的,表明套袋果实中药剂主要来源于枝叶运输,经果柄进入果实后易向果肉累积;在果实未套袋情况下,施药后72 h 6种杀虫剂在果肉中的含量均高于套袋果实果肉中的,分别是套袋果实果肉中含量的7.75、3.52、3.36、6.57、2.92和3.06倍,表明套袋可有效降低果实中该类药剂的残留量。储藏试验结果表明:直接向果面喷施6种新烟碱类杀虫剂后,药剂主要存在于果皮中,施药后14和21 d在果肉中的含量均低于最低检测浓度,表明储藏期果皮为该类药剂的主要残留部位,且不易向果肉中转移。     

利用Monte-Carlo模拟再评估梨火疫病病菌随水果果实的入侵风险

以梨火疫病随进境苹果果实传入的可能性为例，利用Monte-Carlo模拟方法评估有害生物的入侵风险。按照4种不同场景分别建立B分布来拟合入境水果中感染梨火疫病的比率，利用Pert分布拟合进口量。模拟表明，在4种场景下，最可能出现病害的时间分别为4702、3458、216和105年，在第4种场景即对入境苹果果实无任何检疫要求的情形下，出现发病的最少年份为14年。结果表明，传入风险随入境数量的增加而增加。     

A new scab‐like disease on apple caused by the formerly saprotrophic fungus Venturia asperata

Atypical scab‐like symptoms were reported for the first time in 2007 in the south of France on fruits of apple cultivars carrying the Rvi6 (=Vf) major resistance gene to Venturia inaequalis. With microscopic observations, nucleotide sequence data and pathological tests, it was shown that the causal agent was Venturia asperata. Scanning electron microscopy was used to compare its infection process and conidiogenesis to those of Venturia inaequalis on apple and Venturia pirina on pear. Venturia asperata produced fewer hyphae and fewer spores than the two other Venturia species, and resulted in weaker symptoms. This fungal species was previously described as a saprotroph on apple leaf litter. This is the first report of damage on apple fruits caused by V. asperata. Changes in host and cultural practices may have created a new context favourable for the emergence of this pathogen. It was also detected on symptomless leaves and on overwintered leaves on the ground. Pseudothecia developed on overwintered leaves and released ascospores over a 2‐month period from the end of March until the end of May, suggesting that the fungus is able to survive from season to season. However, it is not yet known if this new disease will establish over coming years and become an emergent disease.     

Characterization of a new Apple dimple fruit viroid variant that causes yellow dimple fruit formation in ‘Fuji’ apple trees

A 303-nucleotide viroid was isolated from an apple tree (Malus × domestica, ‘Fuji’) cultivated in Japan. The viroid had 84.9% overall nucleotide sequence homology to Apple dimple fruit viroid (ADFVd), a member of Pospiviroidae, reported from Italy. This viroid differed from the Italian variant by 47 mutations (38 substitutions, six deletions and three insertions), and most of these mutations occurred on either side of the central conserved region. The leaves and branches of the infected trees did not have any disease symptoms, but the fruits were dimpled and yellow. The infected scions were top-grafted onto a healthy ‘Fuji’ apple tree, which tested positive for this viroid in a northern hybridization analysis, and yellow dimple fruits were produced in the second growing season. We propose that this viroid is a new variant of ADFVd and causes yellow dimple fruit formation in ‘Fuji’ apple trees.     

侵染小苹果的苹果锈果类病毒的检测和全序列分析

小苹果是抗寒海棠类与大苹果的杂交后代,因耐寒能力强,口感好,被广泛用于嫁接与育种材料,是我国寒凉苹果产区宝贵的种质资源。苹果锈果类病毒(Apple scar skin viroid,ASSVd)侵染苹果后引起果实表面产生锈状斑、花脸、畸形等症状,严重降低果实品质和市场价值。2013年在调查苹果病毒病时发现北京市延庆县种植的小苹果表现出典型畸形症状,应用RT-PCR方法对其进行检测后经测序和序列分析表明,小苹果被苹果锈果类病毒侵染。克隆此分离物(ASSVd-YQ)全基因组序列,分析后得到其基因组全长为329个核苷酸,系统发育分析表明该分离物与来自不同国家和地区的ASSVd分离物间的进化关系极近。二级结构预测表明,该分离物的中央保守区与末端保守区与ASSVd参考序列相同。这是对侵染小苹果的ASSVd的首次检测和鉴定。