Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2017-06-20T16:31:34Z No. of bitstreams: 1 texto completo.pdf: 443327 bytes, checksum: 5dacc858720c3f3f3562b9c76b172d07 (MD5) / Made available in DSpace on 2017-06-20T16:31:34Z (GMT). No. of bitstreams: 1 texto completo.pdf: 443327 bytes, checksum: 5dacc858720c3f3f3562b9c76b172d07 (MD5) Previous issue date: 2001-02-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Objetivou-se avaliar o controle biológico de B. cinerea por C. rosea, como componente do manejo integrado do mofo cinzento em roseiras, com as seguintes hipóteses de trabalho: i- C. rosea pode colonizar endofiticamente, diferentes tecidos de roseira, em diferentes estádios de desenvolvimento; ii- C. rosea possui habilidade saprofítica para se estabelecer na comunidade microbiana dos restos culturais de roseira; iii- C. rosea coloniza eficientemente ferimentos nos tecidos de roseira e limita a colonização do patógeno; e iv- C. rosea reduz eficientemente a produção de inóculo de B. cinerea em condições de cultivo protegido. Clonostachys rosea germinou, estabeleceu endofiticamente e esporulou abundantemente, em tecidos maduros, senescentes ou mortos. A germinação foi mais alta em tecidos mortos (>98% de conídios germinados) que em folhas e pétalas maduras e senescentes (31% a 47%). Quando folhas maduras foram feridas antes da aplicação de C. rosea, o número de conídios germinados dobrou, mas a área com esporulação do fungo não se alterou e foi alta (>75%). Em folhas maduras, aplicou-se C. rosea imediatamente ou até 24 h após ferimento, e, a seguir, inoculou-se B. cinerea; a germinação do patógeno reduziu-se em até 41% e a esporulação em mais de 99%. O período de 24h de alta umidade, antes das aplicações em folhas senescentes e mortas, estimulou o crescimento de fungos indígenas presentes e reduziu a esporulação de C. rosea e B. cinerea. Em folhas mortas, a associação de fungos indígenas com C. rosea contribuiu para o controle do patógeno. Entretanto, quando aplicados em alta densidade de esporos, Penicillium sp. e Alternaria alternata interagiram negativamente com C. rosea e reduziram sua eficiência em 16 e 21%, respectivamente. Em folhas, estudou-se o efeito de infestações de pulgões (Macrosiphum rosae L.) e de ácaros (Tetranychus urticae Koch) no crescimento e esporulação de C. rosea e B. cinerea e na supressão do patógeno pelo antagonista. A germinação dos dois fungos foi maior nas folhas previamente infestadas por pulgões e ácaros. Naaplicação combinada C. rosea+B. cinerea, em folhas não infestadas, o antagonista suprimiu a germinação do patógeno em mais que 50%, mas, nas infestadas, a germinação do patógeno foi alta (>75%). A infestação com pulgões e ácaros aumentou significativamente a esporulação de C. rosea, independentemente da presença de B. cinerea, e a de B. cinerea, quando inoculado isoladamente. Entretanto, na aplicação combinada, o antagonista suprimiu quase que completamente a esporulação do patógeno, tanto nas folhas infestadas quanto nas não infestadas. Em condições de casa de vegetação, avaliaram-se os efeitos de C. rosea na esporulação de B. cinerea e de variáveis climáticas sobre a colonização dos restos culturais de roseiras (‘Sônia’ e ‘Red Success’) por ambos os fungos. Em ambas as cultivares, a esporulação do patógeno foi consistentemente reduzida em 30 a 50% nos tratamentos onde se aplicou C. rosea (C. rosea e C. rosea+mancozeb, para ‘Red Success’, e C. rosea, para ‘Sônia’). Na aplicação de C. rosea+mancozeb, a esporulação do antagonista reduziu-se em 10 a 15%, ao longo do ensaio, apesar de não ter reduzido significativamente o controle da esporulação de B. cinerea. Nos tratamentos onde foi aplicado, C. rosea estabeleceu-se eficientemente nos restos culturais de roseira, em vista do incremento da sua esporulação a cada avaliação, pelo alto valor da área abaixo da curva de esporulação do antagonista e pela redução crescente na esporulação de B. cinerea. Entretanto, não houve redução significativa da incidência da doença, provavelmente, porque as aplicações de C. rosea iniciaram-se ao final de janeiro, quando a epidemia do mofo cinzento já estava em estádio avançado; não se realizaram práticas de saneamento ao longo do ensaio; e nem todas as roseiras da casa de vegetação foram tratadas com C. rosea, o que permitiu a multiplicação do patógeno. Entretanto, espera-se que, em casas de vegetação, mesmo sob condições favoráveis ao patógeno, a aplicação de C. rosea ao longo de vários ciclos produtivos possa reduzir a população de B. cinerea e, conseqüentemente, a incidência do mofo cinzento em botões. A umidade relativa máxima foi o principal fator de estímulo à colonização de ambos os fungos, por sua influência direta no teor de umidade dos restos culturais; enquanto a umidade relativa mínima e a temperatura máxima reduziram a colonização de ambos, por estarem associadas ao dessecamento dos restos. O fato de os requerimentos ambientais para os dois fungos serem similares é relevante em termos do estabelecimento de estratégias de controle biológico de B. cinerea. / To evaluate the biological control of B. cinerea by C. rosea as a component of the integrated management of rose gray mould, the following hypothesis were tested: i- C. rosea is able to grow endophyticaly on different rose tissues at different developmental stages; ii- C. rosea is able to establish on the microbial community of rose debris; iii- C. rosea is able to colonize wounds and restrict the growth of the pathogen in rose tissues; and iv- C. rosea can inhibit B. cinerea sporulation on rose debris in commercial greenhouse. Clonostachys rosea germinated, established, and sporulated abundantly on mature, senescent, and dead tissues. Germination was higher on dead tissues (>98%) than on mature and senescent tissues (31% to 47%). On wounded mature leaves, germination of C. rosea was twice higher than on non-wounded leaves. The area covered by conidiophores was not affected by wounds and was high (>75%) on all instances. On mature leave that were wounded, inoculated with C. rosea immediately or until 24 h after wounded, and challenge inoculated with the pathogen, the germination of B. cinerea was reduced by 41% and the sporulation on more than 99%. When senescent and dead leaves were subjected to a 24h of high humidity before the inoculations, the growth of indigenous fungi was stimulated and the sporulation of both C. rosea and B. cinerea was reduced. The association of the indigenous fungi with C. rosea contributed for the control of the pathogen on dead leaves. However, when applied on high inoculum density, Penicillium sp. and Alternaria alternata interacted negatively with C. rosea and reduced the antagonist efficiency by 16 and 21%, respectively. The effects of aphids (Macrosiphum rosae L.) and mites (Tetranychus urticae Koch) infestations on growth and sporulation of C. rosea and B. cinerea and on the control of the pathogen by the antagonist were evaluated on rose leaves. When applied alone, the germination of both fungi was greater on infested leaves than on the control leaves. In the combined application, C. rosea inhibited the germination of the pathogen on non-infested leaves by 50%. However, on infested leaves the germination of B. cinerea was high (>75%) despite the presence of the antagonist. Similarly, the infestations of aphids and mites increased the sporulation of both B. cinerea and C. rosea when each fungus was applied alone. However, in the combined application C. rosea inhibited the sporulation of B. cinerea on more than 99% on infested and non-infested leaves. The reduction on B. cinerea sporulation by C. rosea and the effects of climatic factors on pathogen and antagonist growth on rose debris of ‘Sônia’ and ‘Red Success’ plants were evaluated in a plastic covered greenhouse. For both cultivars, B. cinerea sporulation was consistently reduced by 30 to 50% on the treatments were C. rosea was applied (C. rosea and C. rosea+mancozeb, for ‘Red Success’, and C. rosea, for ‘Sônia’). When C. rosea was associated with mancozeb, fungal sporulation was reduced by 10 to 15%, but the efficiency of the antagonist in controlling pathogen sporulation was not significantly reduced. C. rosea established efficiently on rose debris, as verified by the increment of the antagonist sporulation at each evaluation, the high values of area under sporulation curve, and the crescent reduction on B. cinerea sporulation. However, the incidence of gray mould was not significantly reduced, probably due to three main reasons: the applications of C. rosea started by the end of January, when gray mould epidemic was advanced; no sanitation practices were performed during the experiment; and the production of B. cinerea spores on border plants (untreated) in the greenhouse. The daily maximum relative humidity was the main factor that stimulated the debris colonization by both fungi, probably by its influence on the humidity content of the debris. The daily minimal relative humidity and maximum temperature, probably because of their association to the debris dryness, reduced the growth of both fungi. The find that the environmental requirements for C. rosea and B. cinerea are similar can be of paramount importance to establish a biocontrol strategy against the pathogen. From the present and previous studies, the continuous applications of C. rosea can be expected to markedly reduce inoculum production by B. cinerea and, consequently, gray mould incidence in rose production systems, regardless the favorable conditions for the pathogen in the greenhouse. / Tese importada do Alexandria

At present, the global population is increasing, while soil and fresh water resources for crop production are declining. It is important to adopt sustainable practices to optimise the use of limited natural resources without compromising the environment, and to enhance continuous production in the long term. The rapid growth of UK strawberry industry has been achieved through the precision use of varieties, nutrients and polythene tunnels. This intensive production has caused significant environmental impacts especially Greenhouse Gas (GHG) emissions from the production. Strawberry powdery mildew (Podosphaera aphanis) is a major fungal disease affecting strawberry production worldwide particularly in polythene tunnels. The disease can result in yield losses of up to 70% of the crop. A ruleQbased system was used in the field trials to predict high risk days of P. aphanis development, taking into account the optimal environmental conditions conducive to conidial germination and disease development. The results (Chapter 3) showed that the use of this prediction system achieved satisfactory control of P. aphanis in commercial strawberry production, with reduced fungicide applications compared with commercial spray programme. The results were consistent in two consecutive years and on different varieties. In addition, it was suggested that the use of the prediction system may also lead to lower GHG emissions associated with fewer fungicide applications, thereby benefit strawberry growers both environmentally and economically. Results from 2014 & 2015 silicon fertigation trials showed that the use of a silicon nutrient via the fertigation system reduced the strawberry susceptibility to P. aphanis and twoQspotted spider mites (Tetranychus urticae Koch) in two consecutive years on different varieties (Chapter 4). In both years, crops received the silicon nutrient only without fungicides had both lower rate of epidemic (r) and lower value of Area Under the Disease Progress Curve (AUDPC) (r = 0.0036, AUDPC = 475 in 2014; r = 0.001, AUDPC = 267 in 2015) compared with the untreated control (r = 0.0042, AUDPC = 662 in 2014; r = 0.0011, AUDPC = 281 in 2015). Silicon also delayed the epidemic buildQup in the silicon nutrient only treatment for approximately two weeks compared with the untreated control. Crops from the silicon nutrient plus fungicides treatment had lower susceptibility (r = 0.0012 in 2014; r = 0.0004 in 2015) than those from the fungicides only treatment (r = 0.0017 in 2014; r = 0.0005 in 2015) suggesting that the silicon nutrient may also enhance fungicides performance in reducing the epidemic buildQup when used together. Moreover, the presence of T. urticae on strawberry leaves was significantly lower (P < 0.001) in plants treated with the silicon nutrient than those without. In addition, initial results suggested that silicon may play a positive role in raising °Brix of strawberry leaf petiole, improving pollen viability, and influencing the length of flower receptacle and stamens. Maltmas Farm has a wide range of semiQnatural habitats that provide food and nesting resources for wild pollinators. Hoverflies, bumblebees and solitary bees were found to be the main wild pollinators that pollinate commercial strawberries at Maltmas Farm (Chapter 5). The number of pollinators in tunnels or open fields significantly correlated with the abundance of strawberry flowers (P < 0.05). Pollinator presence also differed between groups throughout the day and over the seasons. Hoverflies appeared early in the day and were abundant in summer months; bumblebees and solitary bees were present most of the day and throughout the season, whereas honeybees were only active in sunny days. Temperatures, relative humidity and cloud coverage also affected pollinator presence. In addition, pollinator activity was not significantly (P > 0.05) affected by the application of the silicon nutrient via the fertigation system. The integrated use of the prediction system (to reduce fungicide applications and subsequent GHG emissions), the silicon nutrient (to reduce crop susceptibility to P. aphanis and T. urticae), and sustainable farmland management (to encourage the presence of wild pollinators) could help strawberry growers to achieve a more sustainable production.

The spider mite occurrence, on soybean (Glycine max (L.) Merril), is sporadic and associated whit dry periods. Recently, in continuous years, was reported mite outbreaks in soybean, in some sites of Rio Grande do Sul State. In this context two research was conducted, one in summer crop 2004/05 and other in 2005/06. The first was carried for study the mite occurrence and geographic distribution, on soybean, from some place of Rio Grande do Sul State. The second was conducted for study the effect of the two soybean cultivars and of some weed management systems on mite density and study their population dynamic on soybean. In summer crop 2004/05 was carried some mite samplings in soybean field at State. The mite species found, all beloung to the Tetranychidae family, are Mononychellus planki (McGregor), Tetranychus desertorum Banks, T. gigas Pritchard & Baker, T. ludeni Zacher and T. urticae Koch. Most of this species are well distributed in the diferents sampling regions of this study. From the results was made a species distribution map and a taxonomic key. In summer crop 2005/06, in Santa Maria, RS, 11 treatments was study. Its was constitute in two soybean cultivars, one transgenic glyphosato-tolerant and other non-transgenic, every one whit five weed management systems: (1) without management; (2) hand management; (3) herbicide bentazone + sethoxydim; (4) bentazone only; (5) sethoxydim only. The 11th treatment was the herbicide glyphosate sprayed on the transgenic soybean. The mite species found in this study are M. planki and T. gigas. The weed management systems is more determinant, on the spider mite population on soybean, than the soybean cultivar. The mite population presenteded inverse correlation whit weed infestation and weed density. The climatic fators determined the mite population flutuation and the population peak occured in the initial period of soybean pods development. / A ocorrência de ácaros-praga em soja (Glycine max (L.) Merril) é esporádica e está, comumente, associada à períodos de estiagem. Recentemente, em safras seguidas, foram observados ataques severos de ácaros à soja em algumas regiões do estado do Rio Grande do Sul. Neste contexto foram realizados dois experimentos, um na safra agrícola 2004/05 e outro em 2005/06. O primeiro teve objetivo de estudar a ocorrência e a distribuição geográfica de ácaros fitófagos, associados à soja, em municípios de seis regiões produtoras do estado do Rio Grande do Sul. O segundo objetivou avaliar o efeito de duas cultivares de soja e de diferentes sistemas de manejo de plantas daninhas sobre a densidade populacional de ácaros em soja e estudar a dinâmica populacional destes ácaros na cultura. Em 2004/05 foram realizadas amostragens de ácaros em lavouras de soja no Estado. As espécies de ácaros encontradas são Mononychellus planki (McGregor), Tetranychus desertorum Banks, T. gigas Pritchard & Baker, T. ludeni Zacher e T. urticae Koch, todos são tetraniquídeos. A maior parte destas espécies estiveram bem distribuídas nas diferentes regiões amostradas neste levantamento. Com base nestes resultados foi elaborado um mapa com a distribuição das espécies e uma chave de identificação. Em 2005/06 foram estudados, em Santa Maria, RS, 11 tratamentos. Estes consistiram em duas cultivares de soja, uma transgênica glifosato-tolerante e a outra não-transgênica, cada uma sob cinco sistemas de manejo de plantas daninhas: (1) sem controle; (2) arranquio manual; (3) manejo tradicional com os herbicidas bentazona e setoxidim; (4) apenas com bentazona; (5) apenas com setoxidim. E adicionalmente um tratamento com o herbicida glifosato sobre a cultivar de soja transgênica. Os ácaros-praga ocorrentes foram M. planki e T. gigas. A densidade populacional destes ácaros em soja foi mais afetada pelos sistemas de manejo de plantas daninhas do que pela cultivar, e esteve inversamente correlacionada com a quantidade e diversidade de plantas daninhas. A flutuação populacional destes ácaros foi influenciada por fatores climáticos e o pico populacional ocorreu na fase de início da formação de legumes da soja.