Influence of simulated rainfall on efficacy of fluazinam,chlorothalonil and iprodione for dollar spot control in creeping bentgrass

Efficacy of foliar applied fungicides following simulated rainfall for the control of dollar spot (caused by Sclerotinia homoeocarpa F.T. Bennett) was assessed in a two-year field study on creeping bentgrass (Agrostis stolonifera L.) turf maintained as a golf course fairway. The study was conducted as a randomized complete block design with a factorial arrangement. Fluazinam (0.8 kg a.i. ha⁻¹), chlorothalonil (3.79 kg a.i. ha⁻¹) or iprodione (1.5 kg a.i. ha⁻¹) were applied, then subjected to simulated rainfall (2.54-mm) at intervals of 15-, 30-, 60-min post-application, or no simulated rain. In most cases, simulated rainfall occurring ≤60 min post-application had greater disease than no rain plots; however, few differences occurred among rainfall intervals ≤60 min. Fluazinam provided the greatest dollar spot reduction regardless of simulated rainfall interval throughout the study. Chlorothalonil was most susceptible to losses in efficacy due to simulated rainfall, resulting in the greatest disease incidence of those fungicides evaluated. Iprodione was comparable to chlorothalonil during high disease pressure, although during moderate disease pressure it controlled dollar spot for approximately 7 days before disease increased in plots receiving simulated rain compared to those without simulated rain. These data demonstrate that efficacy of fungicides applied for dollar spot control are affected by rain, and differ in their ability to control disease following post-application rain events. Fluazinam, a recently introduced contact fungicide for use on turfgrass, can provide improved control compared to chlorothalonil or iprodione when rain is eminent.     

Persistence of chlorpyrifos residues in potatoes and the effect of processing

Summary Chlorpyrifos was sprayed on the ridges and foliage of potato plants at 0.4, 0.5 and 0.6 kg a.i./ha 21 days after planting (single spray) and repeated 21 days after the first spray (double spray) to control cutworms (Agrotis sp.). In unprocessed (i.e. not washed, boiled or peeled) potatoes, the residues persisted above the permitted level of 0.10 ppm on several sampling dates. Residues decreased with the time interval between spraying and sampling. Processing potatoes (i.e. washing, boiling followed by peeling) removed the toxicant to a considerable extent. Storing potatoes from chlorpyrifos-treated plots in country stores for 30 days after normal harvest reduced residues to below the detectable level irrespective of the application rate.

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Zusammenfassung Feldversuche mit sieben Behandlungen in vier Wiederholungen mit randomisierter Blockanlage wurden w?hrend des Herbstes 1979–80 und 1980–81 in der zentralen Kartoffelforschungsstation in Jalandhar (Punjab, Indien) durchgeführt, um die Rückst?nde des Insektizids Chlorpyrifos in Kartoffelknollen zu bestimmen. Chlorpyrifos wird eine Wirkung gegen Erdraupen (‘cutworms’),Agrotis sp., zugeschrieben. Es wurde auf Reihen und Kraut mit 0,4, 0,5 und 0,6 kg aktiver Substanz pro Hektar, einmal 21 Tage nach dem Pflanzen (Einfachspritzung) und dann 21 Tage sp?ter (Doppelspritzung) ausgebracht. Die Rückst?nde in den Kartoffelknollen wurden anhand der kolorimetrischen Methode von Getz & Watt (1964) bestimmt. In unverarbeiteten Kartoffeln (d.h. nicht gewaschen, gekocht oder gesch?lt) verblieben Rückst?nde oberhalb der erlaubten Grenze von 0,10 ppm bei zahlreichen Terminen der Probenahme. Die Mengen nahmen mit der Zeit zwischen Spritzen und Probenahme ab. Kartoffelverarbeitung (d.h. Waschen, Kochen mit anschliessendem Sch?len) hatte starke Reduzierung des Giftstoffes zur Folge. 30-t?gige Lagerung in l?ndlichen Lagern nach normaler Ernte reduzierte die Rückst?nde unter die Erfassungsgrenze, in beiden Jahren und bei allen Dosierungen. Die detaillierten Daten für die Rückst?nde werden in den Tabellen 1 und 2 gezeigt.

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Résumé Des essais de plein champ comprenant 7 traitements à 4 répétitions dans un dispositif à blocs randomisés ont été réalisés sur la Station de recherche de la pomme de terre à Jalandhar (Punjab) en Inde au cours des automnes 1979–80 et 1980–81, afin de déterminer les teneurs en résidus de l'insecticide chlorpyrifos dans les tubercules de pommes de terre. Le chlorpyrifos est un produit efficace contre les larves d'Agrotis sp. Il fut appliqué sur buttes et sur feuillage à la dose de 0,4, 0,5 et 0,6 kg de matière active à l'hectare, 21 jours après la plantation (une seule application), ou encore 21 jours après (en double application) puis les résidus dans les tubercules furent déterminés par la méthode colorimétrique de Getz et Watt (1964). Dans les tubercules non transformés (c'est-à-dire sans lavage, sans cuisson ou pelage) les teneurs en résidus étaient au dessus du seuil de tolérance de 0,10 ppm dans plusieurs échantillons. Les pommes de terre transformées (après lavage, cuisson et pelage) avaient beaucoup moins de résidus. La conservation dans les batiments de stockage de pays, pendant 30 jours après une récolte normale, a permis de réduire les teneurs en dessous du seuil décelable au cours des 2 années, quelle que soit la dose testée. Les teneurs en résidus sont détaillées dans les tableaux 1 et 2.

     

Management of the Colorado potato beetle using the entomogenous fungusBeauveria bassiana

Small field plots of Katahdin potatoes on Long Island, NY were treated 6 times in 1980 for control of Colorado potato beetle (CPB)Leptinotarsa decemlineata (Say), Coleoptera: Chrysomelidae, using either the entomogenous fungusBeauveria bassiana (Balsamo) Vuill. (Bb) at 5x 10¹³ colony forming units/ha or fenvalerate at 0.227 kg active ingredient/ha. No significant differences were found between Bb and fenvalerate treatments in egg mass size and viability or in the total foliage consumed by first generation CPBs. First generation CPB larval populations were significantly higher in Bb plots. Oviposition by first generation adults and second generation beetle populations were higher in fenvalerate plots. Average yield was 29.4 metric tons/ha in fenvalerate plots and 24.6 metric tons/ha in Bb plots (a 16% reduction), but nearby untreated plots were completely defoliated by July 24 and yielded <7 metric tons/ha (> 60% reduction).     

Mitochondrial genome sequences illuminate maternal lineages of conservation concern in a rare carnivore

Background

When a specimen belongs to a species not yet represented in DNA barcode reference libraries there is disagreement over the effectiveness of using sequence comparisons to assign the query accurately to a higher taxon. Library completeness and the assignment criteria used have been proposed as critical factors affecting the accuracy of such assignments but have not been thoroughly investigated. We explored the accuracy of assignments to genus, tribe and subfamily in the Sphingidae, using the almost complete global DNA barcode reference library (1095 species) available for this family. Costa Rican sphingids (118 species), a well-documented, diverse subset of the family, with each of the tribes and subfamilies represented were used as queries. We simulated libraries with different levels of completeness (10-100% of the available species), and recorded assignments (positive or ambiguous) and their accuracy (true or false) under six criteria.

Results

A liberal tree-based criterion assigned 83% of queries accurately to genus, 74% to tribe and 90% to subfamily, compared to a strict tree-based criterion, which assigned 75% of queries accurately to genus, 66% to tribe and 84% to subfamily, with a library containing 100% of available species (but excluding the species of the query). The greater number of true positives delivered by more relaxed criteria was negatively balanced by the occurrence of more false positives. This effect was most sharply observed with libraries of the lowest completeness where, for example at the genus level, 32% of assignments were false positives with the liberal criterion versus < 1% when using the strict. We observed little difference (< 8% using the liberal criterion) however, in the overall accuracy of the assignments between the lowest and highest levels of library completeness at the tribe and subfamily level.

Conclusions

Our results suggest that when using a strict tree-based criterion for higher taxon assignment with DNA barcodes, the likelihood of assigning a query a genus name incorrectly is very low, if a genus name is provided it has a high likelihood of being accurate, and if no genus match is available the query can nevertheless be assigned to a subfamily with high accuracy regardless of library completeness. DNA barcoding often correctly assigned sphingid moths to higher taxa when species matches were unavailable, suggesting that barcode reference libraries can be useful for higher taxon assignments long before they achieve complete species coverage.     

Influence of Garlic Intercropping or Active Emitted Volatiles in Releasers on Aphid and Related Beneficial in Wheat Fields in China

In order to develop biological control of aphids by a "push-pull"approach, intercropping using repellent emitting plants was developed in different crop and associated plant models. Garlic is one of the potential plant that could be inserted in crops to decrease the pest occurrence in neighboring crop plots. In this study, field works were conducted in wheat fields in Langfang Experimental Station, Hebei Province in China from October 2009 to July 2010 during wheat developmental season. The effect of wheat intercropping with garlic but also the volatiles emission on the incidence of the English grain aphid, Sitobion avenae Fabricius (Homoptera: Aphididae) was assessed. Natural beneficial occurrence and global yields in two winter wheat varieties that were susceptible or resistant to cereal aphid were also determined comparing to control plots without the use of garlic plant intercrop nor semiochemical releaser in the fields. S. avenae was found to be lower in garlic oil blend treatment (GOB), diallyl disulfide treatment (DD) and wheat-garlic intercropping treatment (WGI) when compared to the control plots for both two varieties (P<0.01). Both intercropping and application of volatile chemicals emitted by garlic could improve the population densities of natural enemies of cereal aphid, including ladybeetles and mummified aphids. Ladybeetle population density in WGI, GOB and mummified aphids densities in WGI, DD were significantly higher than those in control fields for both two varieties (P<0.05). There were significant interactions between cultivars and treatments to the population densities of S. avenae. The 1 000-grain weight and yield of wheat were also increased compared to the control. Due to their potential alternatives as a biological control agent against cereal aphid, garlic intercropping and related emitted volatiles are expected to contribute to the further improvement of integrated pest management systems and to potentially reduce the amount of traditional synthetic pesticides applied in wheat fields.     

贵州省烟蚜遗传多样性分析

【目的】分析贵州省各生态区烟蚜（Myzus persicae）种群间是否存在遗传差异及其差异程度,探明贵州烟蚜种群异质性及种群分化情况,揭示变异发生规律及其机理,为指导虫情监测以及综合治理提供理论依据。【方法】用SSR分子标记技术对贵州省25个主要烟区的烟蚜种群进行遗传多样性分析。【结果】25个地理种群中大部分的种群呈中度分化,个别种群呈高度分化;种群遗传分化及与地理距离、海拔之间的关系分析表明,种群间的遗传距离与地理距离无显著相关性,遗传一致度与海拔差距无相关性。烟蚜种群的系统发育分析表明,25个地理种群大致分为3部分。【结论】种群的遗传分化不符合地理隔离模式,贵州省烟蚜各种群的种群分化复杂,其原因可能与贵州省特殊的地形和气候有关。     

生态恢复方式对喀斯特土壤节肢动物群落特征的影响

为了解不同生态恢复方式对土壤节肢动物群落特征的影响,2012年2月对喀斯特地区撂荒地、退耕还林地和自然林(对照)进行了土壤节肢动物调查。结果表明:在调查区共捕获土壤节肢动物25 898只,隶属7纲18目95科146类。各生境土壤节肢动物类群数和密度-类群指数无显著差异,自然林和退耕还林地个体密度显著高于撂荒地。撂荒地土壤节肢动物优势类群组成与自然林、退耕还林地明显不同,自然林和退耕还林地土壤节肢动物优势类群组成相对接近。喀斯特退化生态系统生态恢复方式对土壤节肢动物群落特征有显著影响,植被差异是影响土壤节肢动物群落特征的主要因素,退耕还林更有利于土壤节肢动物的恢复。     

柑桔全爪螨噻螨酮抗性与敏感品系GST基因表达差异分析

为了明确谷胱甘肽S-转移酶（glutathion S-transferases,GSTs）基因与柑桔全爪螨Panony-chus citri抗性的关系,通过BLAST搜索,对柑桔全爪螨转录组数据库的GST基因进行鉴定,进一步采用RPKM法分析柑桔全爪螨噻螨酮敏感品系（SS）和抗性品系（RS）的GST基因表达差异。从柑桔全爪螨转录组中获得了30条GST基因,11条基因属于Delta家族,10条属于Mu家族,6条属于Kappa家族,2条属于Omega家族,1条属于Zeta家族,同一家族的基因聚在同一进化分支上;两个品系有5条GST基因表达没有差异,此外,抗性品系中有16条发生了下调,有9条GST基因发生了上调;抗性品系上调倍数最高的3个GST基因分别是GSTd6、GSTm5和GSTm4,log₂(RPKM_RS/RPKM_SS)分别仅为1.05、0.74和0.71,荧光定量PCR分析测得上调倍数分别仅为1.13、1.42和1.21,上调倍数均不高。推断,GST基因上调可能不是柑桔全爪螨对噻螨酮产生抗性的重要原因。     

Factors influencing long-term street tree survival in Milwaukee,WI, USA

Street trees are exposed to a variety of site conditions, environmental factors, and physical disturbances which influence their survival in urban areas. This study draws on 25 years of urban forest monitoring data from the city of Milwaukee, WI (United States) to model the impacts of these factors on tree survival for a single cohort of trees. Tree condition, tree size, tree species, and site attributes were measured initially in 1979. These factors were measured again in 1989 and 2005 and compared to construction data for the same area during the study period. Multivariate logistic regression was used to identify factors associated with tree survival. Cross-validation show the final model could successfully predict tree survival nearly 85% of the time. Results indicate that tree survival varied by species. Additionally, trees were more likely to die as trunk diameter increased, planting space width decreased in the tree lawn, and tree condition decreased. Finally, trees adjacent to construction were nearly twice as likely to die as those not exposed to development and redevelopment activities.     

贵州省异绒螨属一新记录种

记述了分布于贵州省的异绒螨属Allothrombium Berlese一新记录种小枕异绒螨Allothrombium pulvinum Ewing,1917。标本保存在贵州大学昆虫研究所（GUGC）。