Parasitoid community of the loreyi leaf wormMythimna (Acantholeucania) loreyi: Novel host-parasitoid associations and their efficiency in the eastern mediterranean region of Turkey

The loreyi leaf worm,Mythimna (Acantholeucania) loreyi Duponchel (Lepidoptera, Noctuidae), is a pest of gramineous crops and causes significant economic damage to maize. In field surveys on maize to determine the parasitoid community and its impact on the pest in the eastern Mediterranean region of Turkey, nine parasitoid species were found associated with immature stages ofM. loreyi: The hymenopteran (Braconidae and Ichneumonidae) parasitoidsCotesia (=Apanteles) ruficrus (Haliday),Chelonus oculator Panzer,Meteorus ictericus Nees,Hyposoter didymator (Thunberg),Sinophorus sp.; and the dipteran (Tachinidae) parasitoidsPseudogonia rufifrons Wiedeman,Exorista rossica Mesnil,Gonia picea (Robineau-Desvoidy) andLinnaemya vulpina (Fallen) — the last three recorded for the first time as parasitoids ofM. loreyi in Turkey.C. ruficrus was the dominant parasitoid species, being recovered from 38.5% of the larvae collected and was also the most prevalent species, existing in 91.0% of the fields in whichM. loreyi was found. Total parasitism levels achieved by braconid species was 41.4%, by ichneumonid parasitoids 4.8%, and by tachinid parasitoids 1.9%. In a separate field experiment, seasonal population fluctuations and natural efficiency ofC. ruficrus onM. loreyi were found to be 35.1% and 42.4%, respectively. Population levels ofC. ruficrus were closely related to fluctuations in the population ofM. loreyi, with parasitism ranging between 0 and 77.3% during the study. http://www.phytoparasitica.org posting Aug. 28, 2005.     

A grower-friendly method to transfer predacious mites to commercial orchards

The establishment of predacious mites in commercial orchards may be accelerated by the transfer of pruned wood in winter and summer from donor orchards to release orchards. Following winter pruning, 3-year-old and older wood is collected and transported as soon as possible in bundles to a release orchard for distribution. If the release orchard is composed of dwarf trees, then one or two bundles of 5 kg each are placed vertically at the base of the trunk of every tree in the block (0.5 to 1 ha); if the trees are of standard size, then four or five bundles used. Following summer pruning, annual shoots and suckers are distributed immediately in a release orchard composed of dwarf trees by placing 12–15 branches on the foliage of fruit-bearing branches; if the release orchard is composed of standard trees, then 50 branches are used. The pruned wood should have 20–25 leaves and not less than one predator per leaf. The release orchard should have a light infestation (two or three mites per leaf) of pest tetranychids. These phytophagous mites would serve as food and help establish the predators. The release orchard grower should develop a pest management program based on the same groups of pesticides used in the donor orchard. http://www.phytoparasitica.org posting Aug. 31, 2005.     

茶薪菇品种比较实验研究

对7个茶薪菇品种进行品种比较实验从中选择出适宜于棉籽壳为主的培养料的优质菌株5个，瓶栽实验生物学效率显著地高于对照品种的生物学效率(53．45％)，达到1％的显著水准。     

哺乳犊牛的消化特点与蛋白质需要

本文从犊牛的消化生理特点出发,综述了犊牛出生后的生理特征及蛋白质、必需氨基酸的需要量,并对代乳品中蛋白质原料进行了论述。     

中国风水侵蚀交错区分布特征分析

风水侵蚀交错带的研究 ,对景观、土地覆盖 /土地利用、全球变化等研究具有重要意义。论文以GIS技术为支撑 ,定量计算出我国风水侵蚀带。在分布特征上 ,主要分布我国北方地区 ,其中以西部沙漠 ,北部山脉沿线为重 ,这种分布与气候、地貌分界有明显联系。 49.6 %风水侵蚀复合带的降水量小于 2 0 0mm。风水侵蚀复合带的土地利用主要以草地为主 ,占 41.8% ,其次为耕地。两种类型的分布 ,草地以与其它土地利用类型交错分布为主 ;而耕地是有重心的分散分布。风水侵蚀复合带的总体侵蚀要强于全国水平。     

发菜形态特征及其与环境因子的关系

通过野外调查和室内观察分析 ,天然发菜原植体的形态主要有柱状和带状两种 ;群体形态有单丝体、团块状、辫状、束状和网状。原植体的形态特征受环境湿度的影响较大 ,在降水量较大的地区 ,发菜原植体增粗 ,直径在 0 .0 5～ 0 .2 5 mm之间 ,带状发菜的比例较大 ,占 30～ 60 % ,吸水后藻体的颜色一般呈棕褐色 ;在降水量较小或极端干旱地区 ,发菜以细丝状为主 ,直径在 0 .0 2～ 0 .2 2 mm之间 ,带状发菜的比例不足 2 5 % ,吸水后藻体的颜色呈绿色或浅棕褐色。发菜群体形态的形成和发育与自身的生长特性有关外 ,主要与环境因子特别是降雨量、地形及自然外力 (地面径流和空气流动 )有关。     

Characteristics for Practical Use of Attenuated Isolate UA-Fukushima of <Emphasis Type="Italic">Tomato mosaic virus</Emphasis>

L₁₁A-Fukushima (L₁₁A-F) derived from attenuated isolate LuA of Tomato mosaic virus (ToMV) has the highest ability to cross protect against virulent ToMV among LuA and its derivatives and is stably inherited. Growth, yield, fruit quality and symptom attenuation of inoculated tomato plants did not differ significantly between L₁₁A-F and L₁₁A. The infectivity of progeny viruses in tomato infected with LuA-F was less than 4% of that with virulent ToMV. From these results, L₁₁A-F appears to possess the properties necessary for practical use. To manage L₁₁A-F strictly, a PCR-based assay to detect trace contamination of virulent ToMV in L₁₁A-F preparations was established. Received 10 June 2002/ Accepted in revised form 30 October 2002     

Comparison of viral RNA populations of pathogenically distinct isolates of Citrus tristeza virus : application to monitoring cross-protection

The population of sequence variants of Citrus tristeza virus (CTV) isolates of different geographic origins and pathogenicity properties was characterized by single-strand conformation polymorphism (SSCP) analysis of cDNA of the genes p18, p13, p20 and p23. The mild isolates analysed here usually yielded a SSCP profile with two DNA bands, suggestive of a predominant sequence variant, whereas the SSCP profile of the most virulent isolates contained more than two DNA bands, indicating that their viral populations are likely to be more complex. The set of SSCP profiles of the four genes allowed identification of individual isolates, but no profile characteristic of a geographic area or a biogroup was found. Sweet orange plants singly inoculated with a mild or with a severe isolate yielded the SSCP profile characteristic of each isolate, whereas the SSCP profile of plants successively inoculated with both isolates was a composite of the two individual profiles. The SSCP profile of plants singly inoculated remained constant, but the profile of doubly inoculated plants varied with time. Plants in which the SSCP profile of the severe isolate became predominant showed stem pitting, and those in which the predominant profile corresponded to the mild isolate remained symptomless. The results indicate that SSCP analysis can be used to study changes in RNA populations of doubly inoculated plants and to monitor cross-protection between mild and severe isolates.     

某些阳离子在大豆胞囊线虫生防系统中的作用

室内测定了不同浓度的 6种阳离子 :钼、硼、锌、铜、锰和铁对大豆胞囊线虫卵的孵化、大豆种子发芽和根系生长 ,以及对线虫生防菌———厚垣轮枝菌菌丝生长的影响。结果发现 ,在供试所有浓度下 ,铜、锰和铁明显抑制大豆胞囊线虫的卵孵化 ,锌具明显刺激作用 ;在供试浓度水平较低时 ,铜、锰和铁对大豆种子发芽及根系生长有轻微抑制 ,锰的抑制较为明显 ,但均不影响进一步发育 ;在供试浓度较低时 ,铜、锰和铁对厚垣轮枝菌菌丝生长无任何影响。铜可作为线虫生防制剂的添加剂。     

敌死虫对不同发育阶段烟粉虱的生物活性测定

敌死虫对烟粉虱成虫具有较强的驱避作用 ,99.1%敌死虫200、100、50倍液药后 2h～120h对黄瓜上烟粉虱的驱避率均在90%以上 ,50倍液处理药后3d的驱避率为98%～100%。药剂处理的非洲菊上烟粉虱成虫产卵量显著低于对照。敌死虫对烟粉虱卵具有一定活性 ,致死中量为10468.6mg/kg ;对若虫活性较高 ,对1、2、3龄若虫的致死中量分别为165.81、199.46、232.38mg/kg ,稀释倍数分别为5976、4968、4264倍。