Onion thrips (Thrips tabaci) and Iris Yellow Spot Virus (IYSV) constitute a pest complex of global concern for allium growers. Yield losses due to onion thrips alone can be heavy, and in tandem with IYSV, these losses can be complete. This study was one phase of a multi-phase research project intent on exploring the potential drivers of thrips and virus infestation in onion. Preliminary observations in participating growers’ fields in northern Utah pointed towards a potential link between weedy field borders and thrips/IYSV infestation in onion. Field work was carried out at the Kaysville experiment station examining the possible relationships between thrips and IYSV incidence in onion and the presence of adjacent weed populations. This research was conducted with the intent of guiding growers’ decisions regarding field border management, and to provide additional insights into onion thrips behavior. While implications for growers remain unclear, thrips preferences regarding host plant utilization were identified, as well as preliminary evidence of additional plant species capable of hosting IYSV.

Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-03-01T14:00:04Z No. of bitstreams: 1 PGPV17MA223.pdf: 188914 bytes, checksum: 40f42384c685cd1e290ca430e4ced46a (MD5) / Made available in DSpace on 2018-03-01T14:00:04Z (GMT). No. of bitstreams: 1 PGPV17MA223.pdf: 188914 bytes, checksum: 40f42384c685cd1e290ca430e4ced46a (MD5) Previous issue date: 2017-02-17 / Capes / The foliar diseases of wheat reduce the area of the photosynthetic plant of the plant, compromising the yield of grains. The objective of this work was to obtain the intensity of foliar diseases, yield and hectoliter of grains in plants of the cultivars: i) TBIO Mestre sprayed with foliar fertilizers (FF) isolated and mixed with fungicides (harvest 2014); ii) TBIO Sinuelo sprayed with fungicides triazole, triazole + strobilurin and morpholine (harvest 2015); iii) the incidence and severity of the fungus Blumeria graminis f.sp tritici on plants sprayed with fungicides in the mode acton preventive and curative. Data were submitted to ANOVA and subsequent comparison of means by the Scott-Knott test or analysis of contrasts (p <0.05). Leaf rust and yellow spot were the predominant diseases in the cultivar TBIO Mestre. The mixture of FF and fungicides didn´t increase the control of rust and leaf spots, the yield and the hectoliter weight of the grains in relation to the isolated use of fungicides. Leaf rust and powdery mildew were the predominant diseases in the trial with the cultivar TBIO Sinuelo. The control of powdery mildew was verified in 40% with the morpholine spray, 41% with triazole and 56% with the triazole + strobilurin mixture. The rust control was 47% with triazoles, 93% with morpholine and 94% with the triazole + strobilurin mixtures. Powdery mildew was the predominant disease in the experiment with Marfim in Muitos Capões. Was detected 32% control of the mildew with the strobilurin + carboxamide mixture, 35% with dithiocarbamates, 68% with triazole + strobilurin and 74% with morpholine. The yellow spot was the predominant disease in the experiment conducted with wheat cultivar TBIO Toruk in Lages. The average control among the 13 fungicides with the greatest reduction of yellow spots AACPDS was 51%. In greenhouse, the pulverized fungicides presented average control of 68 % in preventive action and 56 % curative. It is suggested the control of powdery mildew with triazole + strobilurin, triazole + strobilurin + carboxamide or morpholine. The fungicides of the dithiocarbamate group and the strobilurin + carboxamide mixture don´t have effective control of powdery mildew. The spraying of fungicides resulted in higher grain yield in the four trials conducted in the 2014, 2015 and 2016 crops, with a mean of 669.75 kg ha-1 (18%), with a variation of 413 kg ha-1 (10%) in the cultivar TBIO Mestre in 2014, up to 1,027 kg ha-1 (31%) in the TBIO Sinuelo cultivar in 2015. The wheat grains harvested from the controls of the four field trials obtained 72 hectoliter compared to 76 in the pulverized fungicide / As doenças foliares do trigo reduzem a área foliar fotossintetizante da planta comprometendo o rendimento de grãos. Os objetivos deste trabalho foram obter a intensidade de doenças foliares, rendimento e peso hectolitro de grãos em plantas dos cultivares: i) TBIO Mestre pulverizadas com fertilizantes foliares (FF) isolados e em mistura com fungicidas (safra 2014); ii) TBIO Sinuelo pulverizadas com fungicidas triazol, triazol + estrobilurina e morfolina (safra 2015); iii) Marfim e TBIO Toruk pulverizadas com triazol + estrobilurina, triazol + estrobilurina + carboxamida, estrobilurina + carboxamida e ditiocarbamato (safra 2016) e iv) a incidência e severidade do fungo Blumeria graminis f.sp tritici em planats pulverizadas com fungicidas em modo de ação preventivo e curativo. Os dados foram submetidos à ANOVA e posterior comparação de médias pelo teste Scott-Knott ou análise de contrastes (p<0,05). A ferrugem da folha e mancha amarela foram as doenças predominantes no cultivar TBIO Mestre. A mistura de FF e fungicidas não aumentou o controle de ferrugem e manchas foliares, o rendimento e peso hectolitro de grãos em comparação ao uso isolado de fungicidas. A ferrugem da folha e oídio foram as doenças predominantes no ensaio com o cultivar TBIO Sinuelo. Foi verificado controle de oídio em 40 % com a pulverização de morfolina, 41 % com triazois e 56 % com a mistura de triazol + estrobilurina. O controle de ferrugem foi de 47 % com triazóis, 93 % com morfolina e 94 % com as misturas de triazol + estrobilurina. O oídio foi a doença predominante no experimento com o cultivar Marfim em Muitos Capões. Foi detectado 32 % de controle do oídio com a mistura de estrobilurina + carboxamida, 35 % com ditiocarbamatos, 68 % com a mistura de triazol + estrobilurina e 74 % com morfolina. A mancha amarela foi a doença predominante no experimento conduzido com o cultivar de trigo TBIO Toruk em Lages. A média de controle entre os 13 fungicidas de maior redução da AACPDS de mancha amarela foi de 51 %. Em casa de vegetação, os fungicidas pulverizados apresentaram controle médio de 68 em ação preventiva e 56 % curativa. Sugere-se para controle de oídio fungicidas formulados com triazol + estrobilurina, triazol + estrobilurina + carboxamida ou morfolina. Fungicidas do grupo dos ditiocarbamatos e a mistura de estrobilurina + carboxamida não tem controle eficiente de oídio. A pulverização de fungicidas resultou em maior rendimento de grãos nos quatro ensaios realizados nas safras 2014, 2015 e 2016, com média de 669,75 kg ha-1 (18 %), com variação de 413 kg ha-1 (10 %) no cultivar TBIO Mestre em 2014, até 1.027 kg ha-1 (31 %) no cultivar TBIO Sinuelo em 2015. Os grãos de trigos colhidos nas testemunhas dos quatro ensaios de campo obtiveram 72 de PH médio em comparação a 76 nas parcelas pulverizadas com fungicidas

Made available in DSpace on 2016-12-08T16:44:45Z (GMT). No. of bitstreams: 1 PGPV13MA124.pdf: 862800 bytes, checksum: 52145904b06c7b90decb7d1ef575d2ff (MD5) Previous issue date: 2013-04-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The fungicide application on the control of wheat foliar diseases increase the cost production and contribute to contaminate the environment, if unnecessary sprays would be made. The aim of this work was to analyse the available criteria to the technical assistance concerning to the decisive making about the moment of the fungicide application. The experiments were carried out at field, in the 2011 and 2012 growing seasons in Lages, Santa Catarina State, with the Mirante cultivar wheat. Were tested the following criteria: 1) witness (without fungicide spraying); 2) 1% of incidence of plants; 3) 10% of incidence of plants; 4) 5% of foliar severity; 5) main stem with from five to six tillers; 6) first visible node; 7) third visible node; 8) Economic Damage Threshold (EDT). The reapplications were made based on the period of fungicide mixture protection of azoxystrobin + cyproconazol (60g + 24g a.i. ha-1) + propiconazol (125g a.i. ha-1). The experimental unities were composed by 1.5 x 5 m plots arranged in a randomized blocks design with four replications. The applications were made with a coastal sprayer with pressure generated by CO2 gas delivering 200 L ha-1. In the economic analysis was taken in account the cost of applications, the number of applications, the price of wheat, the disease intensity (area under the disease progress curve AUDPC), control effectiveness based on the intensity disease and components of yield (productivity, mass of one thousand grains and weight of the hectoliter). The data were submitted to ANOVA with means compared by the Tukey`s test. In the two growing seasons, leaf rust, yellow spot and powdery mildew were the predominant diseases. The AUDPC values showed that the criteria 1% and 10% of incidence of plants and from five to six tillers presented lower intensities of disease, with higher control and higher yields, however, they received from three to four applications. The EDT criteria received two to three applications and obtained intermediate values, as well as, the criteria of first visible node that presented intermediate values for the means of incidence and severity and also for the productivity. The criteria of third visible node and 5% of foliar severity began the chemical control later, receiving from one to two applications and showed higher means of incidence and severity, lower control, as well as, a lower productivity of grains / A aplicação de fungicidas no controle de doenças foliares do trigo aumenta o custo de produção e pode contribuir para contaminar o meio ambiente caso sejam feitas aplicações desnecessárias. O objetivo deste trabalho foi analisar os critérios disponíveis para a assistência técnica sobre a tomada de decisão para o momento da aplicação de fungicida. Os experimentos foram conduzidos no campo nas safras agrícolas de 2011 e 2012, em Lages, Santa Catarina, com a cultivar de trigo Mirante. Foram testados os seguintes critérios: 1) Testemunha (sem aplicação de fungicida); 2) 1% de incidência de plantas; 3) 10% de incidência de plantas; 4) 5% de severidade foliar; 5) Colmo principal com cinco a seis afilhos; 6) Primeiro nó visível; 7) Terceiro nó visível; e 8) Limiar de Dano Econômico (LDE). As reaplicações foram feitas com base no período de proteção da mistura dos fungicidas azoxistrobina + ciproconazole (60g + 24g de i.a. ha-1) + propiconazole (125g de i.a. ha-1). As unidades experimentais constaram de parcelas de 1,5 x 5 m arranjadas em delineamento de blocos ao acaso com quatro repetições. As aplicações foram feitas com pulverizador costal com pressão gerada por gás CO2 para equivaler uma vazão de 200 L ha-1. Na análise econômica considerou-se o custo das aplicações, o número de aplicações, o preço do trigo, a intensidade de doenças (área abaixo da curva de progresso de doença - AACPD), a eficácia de controle com base na intensidade de doença e os componentes de rendimento (produtividade, massa de mil grãos e peso do hectolitro). Os dados foram submetidos à ANOVA e as médias comparadas pelo teste de Tukey. Nas duas safras as doenças predominantes foram ferrugem da folha, mancha amarela e oídio. Os valores da AACPD demonstraram que os critérios 1% e 10% de incidência em planta e cinco a seis afilhos apresentaram menores intensidades de doença, com maior controle e maiores produtividades, porém receberam de três a quatro aplicações. Os critérios do primeiro nó visível e LDE receberam de duas a três aplicações e apresentaram valores intermediários para incidência, 8 severidade e produtividade. Os critérios do terceiro nó visível e 5% de severidade foliar iniciaram o controle químico mais tardiamente, recebendo de uma a duas aplicações e demonstraram maiores médias de incidência e severidade, menor controle, bem como menor produtividade de grãos