The accumulation and distribution of pp′DDT and related compounds in an apple orchard .I. residues in the soil

Soils from an orchard sprayed annually (1953-1969) with technical DDT (77% pp′DDT and 22 % pp′DDT) were analysed for residues from 1964 until 1969. The amount of DDT found after 17 years was 21 %pp′DDTout of 27.1 kg/ha applied, and 7 % of pp′DDT out of 7.6 kg/ha. The vertical distribution of residues (pp′DDT, pp′DDE, pp′TDE and pp′DDT) showed a linear relationship between log amount and depth, with approximately 80% in the top 10 cm of soil. At depths from 50 to 210 cm, residue values were too small to be determined (i.e. < 1 ng/g dry wt). The surface distribution in the orchard showed a systematic pattern of circular areas of residues, with maximum values centred at each trunk (7.5 μg/g) and decreasing rapidly to each alley (1.9 ug/g). The levels of pp′DDT had reached a steady state (3-4 kg/ha) and the half-life time was calculated as 3.0 j′ears. pp′DDE (1.8 kg/ha) was the main metabolite of pp′DDT. Small amounts of pp′TDE were also found, pp′DDT was less persistent than pp′DDT, with a half-life time of 1.5 years.     

绿盲蝽越冬卵在苹果园中的空间分布型及抽样技术

近年来绿盲蝽Apolygus lucorum已经逐渐发展成为果树上的重要害虫之一, 对其越冬卵在果树上的空间分布型进行探究具有重要意义?本研究利用6种聚集度指标?Iwao回归方程和Taylor幂法则分析了苹果园中绿盲蝽越冬卵的空间分布型, 同时对苹果园绿盲蝽越冬卵聚集的原因和最适理论抽样数进行了分析与计算?结果显示, 绿盲蝽越冬卵在苹果园呈聚集分布, 并且随着越冬卵密度的增加, 分布越聚集?绿盲蝽越冬卵的种群聚集是由其生活习性与周围环境共同引起的?运用绿盲蝽越冬卵空间分布型参数, 建立Iwao理论抽样数模型, 从而明确不同密度下绿盲蝽越冬卵的最适理论抽样数, 为今后绿盲蝽越冬卵在苹果园内密度的准确调查和种群密度的预测提供了理论依据?     

Recovery in apple trees infected with the apple proliferation phytoplasma: an ultrastructural and biochemical study

ABSTRACT Localization of hydrogen peroxide (H(2)O(2)) and the roles of peroxidases, malondialdehyde, and reduced glutathione in three apple cultivars were compared in healthy trees, trees infected with apple proliferation phytoplasma (APP), and trees that had recovered from the infection. In recovered apple trees, symptoms of the disease and the pathogen had disappeared from the canopy, but phytoplasmas remained in the roots. H(2)O(2) was detected cytochemically by its reaction with cerium chloride to produce electron-dense deposits of cerium perhydroxides.H(2)O(2) occurred in the plasmalemma of the phloem of leaves of recovered apple trees, but not in healthy or APP-infected leaves. In all cultivars, the peroxidase activity detected in tissue from APP-diseased trees was greater than or equal to that of tissue from recovered trees, which equaled or exceeded that of tissue from healthy trees, at two sampling times (May and September). In contrast, the glutathione content of leaves decreased in the reverse order. More malondialdehyde was observed in leaves from recovered trees than in leaves from healthy or APP-infected trees in three of six cultivar-date combinations; in the other three combinations, the malondialdehyde contents of leaves from healthy, infected, and recovered trees were not significantly different from one another. The results suggest that some components of the oxidant-scavenging system in recovered leaves are not very active, leading to an overproduction of H(2)O(2) and, possibly, to a membrane lipid peroxidation.The production of H(2)O(2) appears to be involved in counteracting pathogen virulence.     

The effect on earthworm populations of methods of spraying benomyl in an apple orchard

Compared with high volume (2240 litre/ha) sprays, low (560 litre/ha) and ultra-low volume (45 litre/ha) sprays of benomyl were less toxic to earthworms. The decrease in populations was proportional to the quantity of fungicide deposited on the ground; regression lines, probit (% reduction) on log (fall out in g/ha), are given for populations of Lumbricus terrestris and all species together. The reduction in numbers was similar for all species except L. terrestris and Allolobophora longa, L. terrestris was more susceptible to the deposits than the other species; A. longa was less affected, probably because it was in summer diapause.     

地膜-秸秆双重覆盖模式下果园土壤养分含量研究

为了研究地膜-秸秆双重覆盖模式对渭北旱塬果园土壤养分含量的影响,对5个不同处理(地膜压玉米秆双重覆盖、地膜压短麦秆双重覆盖、长麦秆压地膜双重覆盖、地膜压长麦秆双重覆盖和无覆盖清耕对照)下果园0~100 cm土层深度范围内的土壤养分含量进行测定,并统计了苹果产量。结果表明:地膜-秸秆双重覆盖模式能显著提高果园土壤养分平均含量,并提升养分有效性;其中地膜压短麦秆双重覆盖处理综合效果最佳,土壤有机质、全氮、碱解氮、速效磷、速效钾含量均显著高于无覆盖对照(P0.05),提高比例分别为29.72%、8.82%、19.35%、51.87%、22.66%;碱解氮含量提高比例高于全氮,说明该模式能够提高氮肥有效性。与无覆盖对照相比,地膜-秸秆双重覆盖模式对土壤剖面养分垂直变异影响不明显,均呈现出随深度增加先降低后缓慢递增的趋势。从提高土壤养分含量和提升其养分有效性的角度出发,利用地膜压短麦秆双重覆盖模式进行果园土壤管理可以成为实现渭北旱塬果园高产、优产、稳产的有效途径之一。     

Side effect of some fungicides on the mite population in an apple orchard in Croatia

The research into the side effect of fungicides used in the control of the most serious disease in apples (Venturia inaequalis) i. e. the research into the influence of fungicides on the population of phytophagous mites, was carried out at Nedeliŝće (North-West Croatia) during 1997 and 1998. The study is related to the population of the mites most present in apple orchards, such as red spider mite (Pananychus ulmi) and other mites (Aculus schlechtendali andTetranychus urticae). Fungicides which are known to be effective against scab, i. e.Venturia inaequalis, and used in fruit production in Croatia, were tested in order to investigate their secondary properties which have not yet been studied. The following fungicides were used: cyprodinil, dodine, dichlofluanid + bitertanol (as tank mix), and kresoxim-methyl. The tests were repeated three times; the application time was determined by monitoring the conditions for infection. The treatments were done curatively, i. e. up to 96 h after the onset of infection conditions. The mite population was estimated by the pressing method, which yielded the average number of mites per leaf. All the results were statistically processed by variance analysis and by Duncan’s Multiple Range Test, and are presented graphically and in tables. The paper also presents graphically the climatic conditions, scab infections and application time. The research over two years have shown a pronounced suppressive effect of dichlofluanid + bitertanol on populations of phytophagous mites, while the other fungicides used in the research had a neutral effect on the mite papulation.     

Phenology of the common earwig Forficula auricularia L. (Dermaptera: Forficulidae) in an apple orchard

Abstract

Observational data taken over 13 years, on the phenology and the abundance of the first brood of the common earwig, Forficula auricularia L., in a Dutch apple orchard were analysed. The results are used to indicate a fixed sampling moment for this predator. The fourth instar nymphs emerged between 12 June and 10 July, and the adult stage was reached between 8 and 30 July. The observed phenology, and the number of earwigs in shelter traps, correlated well with the temperature sum in day-degrees above a thermal threshold of 6 C, accumulated from 1 January. Maximum numbers of earwigs could be trapped in the trees when the nymphs of the first brood entered the fourth instar, generally between 600 and 750 day-degrees.     

A comparison of the efficiency of sprays of two drop-size ranges in an apple orchard

A two-season trial of a mist blower-sprayer with improved air-flow characteristics was made to assess the relative efficiency of 120 and 180 μm mass median diameter (MMD) drop-size sprays for the control of apple powdery mildew (Podosphaera leucotricha) and fruit tree red spider mite (Panonychus ulmi Koch) in a hedgerow-type apple orchard. The principal pesticide was binapacryl, applied at two rates for each drop-size. Under typical commercial conditions the smaller drop-size approximately halved the incidence of apple mildew found when the conventional 180 μm MMD drop-size spray was used; there was no conclusive advantage against red spider mite. Unexpectedly large variations occurred in the deposits from the weekly applications and were related to the humidity during spraying.     

Effect of pest management systems on foliage- and grass-dwelling spider communities in an apple orchard in Hungary

Spider communities (Araneae) inhabiting the canopy, the herbaceous layer and the borders, as well as the populations overwintering on the tree trunks of different aged IPM and conventional apple orchards were investigated in Hungary. Abundance and species richness of entire spider communities in IPM plots were significantly higher than in conventional plots, probably owing to the lower toxicity of pesticides used and higher prey densities. In the case of abundance, similar tendencies were observed in web-building and hunting spider guilds. Age of plantations can significantly influence spider density in the canopy, acting through the prey density. In young plantations, where size of the canopy was smaller and density of the pear lace bug (Stephanitis pyri L.) higher, significantly higher numbers of hunting spider communities were present than in old plantations which had been similarly treated. This relationship was not observed for web-building spiders. Diversity of canopy-inhabiting spider communities was higher in old plots, regardless of the treatments. The effect of the border of the orchard on spider communities was investigated and it was found that when selective insecticides were used, migration of spiders into orchards was increased significantly. When broad-spectrum insecticides were applied, spider densities in the canopy did not differ between outer and inner rows of the orchards. The effect of the treatments and orchard age, both on abundance and species richness of overwintering spider communities on the trunk, showed the same result as for canopy spiders, namely significantly larger spider communities were found in IPM plots and in the young plantation than in conventionally-treated plots and in the old plantation. Broad-spectrum insecticides reduced abundance and species richness of spider communities in the herbaceous layer of the conventionally-treated plot. At the same time, the spider communities of the herbaceous layer of the IPM plot did not differ significantly from adjacent herbaceous plants. A significant overlap exists between spider communities of the canopy and herbaceous layer. Despite chemical treatments, migration from the herbaceous layer into the canopy occurs. The effects of chemical treatments on the dominant species are discussed. There were no significant differences between the differently treated plots in abundance of one of the dominant species Oxyopes heterophthalmus Latreille. However, the other dominant species, Cheiracanthium mildei L. Koch, was more abundant in the IPM plots.     

果园螟蛾总科部分种类DNA条形码鉴定

为检验DNA条形码在鳞翅目螟蛾总科蛾类鉴定中的可行性,对采自山西省太原市晋源区螟蛾总科26种78头蛾类标本分别提取了DNA,扩增了全部78头标本的线粒体cox1基因和其中75头标本的核糖体28S基因,并通过构建系统发育树、计算遗传距离及种间差异阈值等方法,对所有标本进行了鉴定和比较分析,检验了国际DNA条形码数据库BOLD(the barcode of life data)系统的鉴定成功率。结果表明,基于cox1基因和28S基因的系统发育树鉴定成功率分别为100.00%和97.14%,BOLD系统的鉴定成功率达到了67.94%。基于最大简约法、邻接法和最大似然法构建的系统发育树,鉴定结果均相同。基于cox1基因的种内遗传距离全部小于1.00%,种内种间的遗传距离形成明显的3.00%阈值现象。研究表明,cox1及28S基因均适用于供试螟蛾总科种类的鉴定,核糖体28S基因可以作为DNA条形码鉴定的辅助基因;BOLD系统数据库仍有待充实,且标本鉴定工作相对滞后;不同聚类分析方法对结果影响很小,其中邻接法计算速度快,更适合DNA条形码大数据的分析。     

PAM保水剂及纳米蒙脱土对果园生草地上部生物量的影响

为了实现果园生草节水效果,采用田间试验方法,研究了半量和常规灌溉条件下,不同用量的PAM保水剂(0,4,8,12 g/m2)和不同用量纳米蒙脱土(0,150,300,450 g/m2)对不同草(紫花苜蓿,黑麦草,白三叶)地上部总生物量的影响.结果表明,半量灌溉条件下,施用PAM保水剂可显著增加3种草的地上部总生物量,适宜剂量为8g/m2,而常规灌溉条件下,不宜施用PAM保水剂.施用纳米蒙脱土可增加3种草的地上部总生物量,半量灌溉条件下,适宜剂量为150 g/m2,常规灌溉条件下,对于紫花苜蓿和黑麦草,适宜剂量为450 g/m2,对于白三叶,适宜剂量为300 g/m2.     

Residues of tetrachlorvinphos and its breakdown products on treated crops. II.—Residues on apples

Apples treated with tetrachlorvinphos (Gardona, trans-isomer of dimethyl 1-(2′,4′,5′-trichloropheny1)-2-chlorovinyl phosphate) insecticide under field conditions in several countries in 1965, 1966 and 1967 have been analysed at intervals after treatment for residues of tetrachlorvinphos itself, its cis-isomer and seven potential breakdown products. Residues of up to 10 ppm of tetrachlorvinphos were detected immediately after the last of three applications of tetrachlorvinphos (diluted to 0.16% active material). The initial half-life of the tetrachlorvinphos was on average about 0.5 weeks under U.K. conditions and only 10% of the tetrachlorvinphos remained unchanged at 2 weeks after application. The overall chemical persistence of the wettable powder formulation was not significantly different from that of the emulsifiable concentrate formulation. Within 8 weeks of the application the residues were mainly of tetrachlorvinphos itself, its cis-isomer and the alcohol 1-(2′,4′-5′-trichlorophenyl)ethan-l-ol, in free and sugar-conjugated forms. The residues of the conjugates of this alcohol (up to 0.92 ppm) were generally present in higher concentration at 6-8 weeks after the application than were the residues of the other components. Whilst residues of other breakdown products were detected on the apples their individual residues were below 0.05 ppm and generally below 0.01 ppm at 6 weeks or more after the last of several applications of tetrachlorvinphos.     

山东烟台地区苹果园和桃园主要害虫及天敌昆虫发生动态

山东烟台地区是我国苹果和桃的重要产区.本研究利用性诱剂诱捕器和黄色粘虫板调查烟台地区果园中主要害虫和其他常见害虫及天敌昆虫的发生动态.结果 表明:山东烟台地区苹果园和桃园中主要害虫—梨小食心虫、桃小食心虫、小绿叶蝉在两个果园中的年发生总量存在一定差异,苹果园桃小食心虫年诱捕量为545.8头/诱捕器,显著高于桃园年诱捕量...     

Detection of apple proliferation phytoplasma by ELISA and PCR in growing and dormant apple trees

Journal of Plant Diseases and Protection - Apple proliferation (AP), caused by a phytoplasma belonging to AP group, is an important vector-borne and graft-transmissible disease of apple trees in...     

Accumulation of phenolic compounds in apple in response to infection by the scab pathogen,Venturia inaequalis

The research dealt with phenolics in healthy versus scab infected apple leaves and fruits. The leaf samples were picked in the period from May to September and the fruit samples at technological maturity. Infection with the Venturia inaequalis fungus enhanced the metabolism of phenolics at the infected sites, especially in the boundary tissue. Tissue infected with Venturia inaequalis showed in comparison to the healthy tissue up to 7.6 times more hydroxycinnamic acids, up to 2.6 times more flavan-3-ols and up to 2.9 times higher values of flavanols. The content level of total phenolics in the infected tissue was 1.3–2.4 times higher than in the healthy leaves and fruit.     

Residues of chlorpyrifos in various crops II. Residues after field treatments

Five agricultural crops were treated with OO-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate (chlorpyrifos) granular or emulsifiable concentrate formulations at dosages from 0.5 to 6.0 kg (a.i.)/ha and at different periods before harvest. Chlorpyrifos residues were determined by gas chromatography after extraction and sweep co-distillation clean-up. Low residue levels were found. The average values in lettuce were 0.046 and 0.070 part/million, in sugar beet leaves 0.037 to 0.128 part/million and roots <0.005 to 0.038 part/million; no chlorpyrifos was detected in carrots, potatoes and cured tobacco leaves at the limit of the method (0.005 part/million).     

Spray deposit cover and fungicide distribution obtained by low and ultralow volume spraying of intensive apple trees

Spray deposit assessments were made on the leaf surfaces in the top, middle and base zones of intensively grown dessert apple trees sprayed by a conventional high volume automatic mast method applying 2250 litres/ha, an experimental low and ulfralow volume tractor mist blower, applying 225 litres/ha at normal dilution, 45 litres/ha at five times normal concentration or 22.5 litres/ha at ten times normal concentration, and a modified proprietary hand-directed fan-disc sprayer applying 225 or 22.5 litres/ha. Fluorescent tracer assessments showed that the high volume method gave heavy cover on upper and lower surfaces of the leaves in all zones, the tractor mist method gave lighter but uniform cover and the fan-disc sprayer gave sparse cover on the upper surfaces at the top and on the lower surfaces at the base zone. The hand-directed low and ultralow volume methods, applying one-tenth of the amounts of copper fungicide/ha, gave deposit levels 5–30 % of those of the high volume method and the tractor mist applications gave 0.8–5.2%. The corresponding captan deposits from 5–6 applications were 12–50% and 10–20%: residual deposits from the ultralow volume applications of the concentrated captan were greater than the low volume applications of the same quantities in dilute form. In general, the order of pest and disease control obtained by the three methods was high volume automatic, fan-disc and experimental mist, and this was related to the order of deposit levels: the order of control by the three volume rates was 2250, 225 and 22.5 litres/ha, and this could be related to the degree of spray cover.     

晋西黄土区常规果农间作模式下 果树遮阴时空分布特征

为探讨晋西黄土区常规苹果树与农作物间作模式条件下不同树龄果树遮阴范围的时空分布特征,提出合理的间作作物种植区域,以山西吉县果农间作条件下4~7 a生苹果树为试验材料,遵循平行光线下的相似性原理,将果树按其树体缩小50倍,制作不同林龄的苹果树3D模型,利用树体模型在研究区进行果树遮阴范围的动态测定。结果表明：（1）在时间上,单株苹果树遮阴面积在一天内随时间先减小后增大,中午12∶00果树遮阴面积最小;在空间上,苹果树遮阴范围整体呈现不等宽弧型分布,且果树北侧遮阴大于南侧遮阴距离0.5~0.6 m。（2）在一天中,4~7 a生苹果树行间均受到同行苹果树(目标果树与邻株果树)的叠加遮阴,遮阴时长为4~9 h。（3）4 m×5 m株行距配置下间作作物的适宜种植区域为1.41~1.91 m,5 m×5 m 株行距配置下间作作物的种植区域为1.63~2.14 m,且种植区域均随树龄的增加而减小。（4）间作作物行间适宜种植区域应采用南北向不等间距种植,并且适宜种植区北向距离大于南向距离0.6~0.7 m。综合研究区常规果农间作配置果树遮阴范围时空分布特征分析,传统果农间作系统下不同树龄时期,间作作物的南北方向等间距种植模式存在不合理性。本研究依据晋西黄土区常规果农间作配置模式果树遮阴范围时空分布特征,提出果农复合系统间作作物的不同株行距配置下不同树龄的间作作物合理种植区,间作作物种植需考虑南北不等间距,且随着树龄增长间作范围应不断缩小。     

Residues of zineb and ethylene thiourea in orchard treated pears and commercial pear products

Zineb and ethylene thiourea (ETU) residues were monitored in Bartlett pears after spraying with zineb (5.04 kg a.i./ha). Zineb dissipated seven times faster in the first 10 days after application than in the subsequent days of the study; ETU residues ranged from 0.02 to 0.01 mg/kg over the 21 day trial. A 3–6% conversion of ethylene-bisdithiocarbamate to ETU was found upon boiling treated pears. Analysis of randomly selected commercially canned pears and baby food pear purée showed no zineb residues but LT0.05 mg ETU/kg was present in four of the six samples of baby food.     

不同灌溉方式对渭北果园土壤水分及水分利用的影响

为了筛选适合渭北黄土高原苹果园的节水灌溉方式,以陕富6号苹果为试材,研究了不同灌溉方式下0～1 m土壤含水率的动态变化规律、土壤储水量和水分利用效率.结果表明:(1)3～10月份,不同层次土壤含水率由高到低为:膜下滴灌＞膜下沟溉≈滴灌＞沟灌＞不灌溉,覆膜与不覆膜之间比较,膜下沟灌＞沟灌,膜下滴灌＞滴灌.(2)6月15日...