979 resultados para Grapevine rust mite
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The garlic (Allium sativum L.) can be naturally infected by a complex of filamentous viruses belonging to the genera Potyvirus, Carlavirus and Allexivirus. Accumulation of these viruses occurs especially by vegetative propagation through cloves. As the cultivated garlic plant does not produce true seed worldwide, virus-free plants can only be obtained by tissue culture of stem apices and thermotherapy. Using these techniques, garlic seeds were produced at the School of Agricultural Sciences - UNESP, Botucatu, and evaluated by RT-PCR for the presence of potyvirus, carlavirus and allexivirus. In the second generation of microcloves propagated in a greenhouse, 6.6% infection was detected, only by allexivirus. In the fourth generation, however, there was 60% incidence by allexivirus, 35% by potyvirus and all negative by carlavirus. The high rate of infection by allexivirus may be related to the greater difficulty of removing the species of viruses belonging to this genus, as observed by other authors, and also based on the infection and transmission of the virus by the mite, Aceria tulipae, during the storage of bulbs from one year to the other. The garlic at the fourth generation corresponds to cloves weighed less than 1 gram and not selected for commercial multiplication. Selection for the size of cloves has a positive effect on the choice of cloves with lower rates of viral infection, as the technique of thermotherapy and tissue culture do not eliminate the virus completely. Results also emphasize the need of fumigation for the garlic seed stored from one year to the other in order to prevent the transmission of allexivirus during storage.
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Pós-graduação em Química - IQ
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Pós-graduação em Química - IQ
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Pós-graduação em Agronomia (Energia na Agricultura) - FCA
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The almost complete absence or misdistribution of water as a natural resource frequently constitute a limiting factor for plant growth and development in the semi-arid northeastern Brazil. In this context, the use of appropriate irrigation techniques is an essential and indispensable factor for proper functioning of the primary and secondary metabolisms in plants. This study aimed to assess the metabolism of the Syrah grapevine in the semi-arid northeastern Brazil, by using three irrigation strategies (controlled deficit irrigation [CDI], deficit irrigation [DI], and full irrigation [FI]). The research was conducted at Embrapa Semiarid (Embrapa-Brazilian Agricultural Research Corporation), Experimental Field of Bebedouro, municipality of Petrolina, state of Pernambuco, Brazil. The statistical design was randomized blocks, with a 3 x 6 factorial scheme. Six samplings were performed throughout the experiment cycle at 54, 60, 73, 87, 101, and 115 days after pruning (DAP). We analyzed the total soluble sugars, reducing sugars, total soluble protein, and invertase activity. Analysis of variance and the F test were performed for all analyzed variables. The means were compared using the Tukey test at 5% significance. At the end of the experiment cycle, DI was found to increase the average acid invertase activity in the plant cell wall. Further, by the end of the experiment cycle, the total soluble sugars and reducing sugars increased in all plants in the three irrigation strategies. Thus, we conclude that it is possible to reduce water consumption in vineyards of the semi-arid northeastern Brazil, without significantly affecting the protein and sugar metabolisms in the plants.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The litchi erineum mite, Aceria litchii (Keifer), is the major pest of litchi, Litchi chinensis Sonnerat (Sapindaceae). This study evaluated the effect of 11 pesticides on the survival of A. litchii as well as on the survival and reproduction of Phytoseius intermedius Evans& McFarlane, the predator most found in association with it in Brazil. The containment of A. litchii in small petri dishes whose bottoms were covered with a solidified paste made of a mixture of gypsum and activated charcoal (9: 1 in volume), kept humid, was shown to be adequate for this type of study. For the evaluation of the effect of pesticides on A. litchii, mites leaving the erinia from the pieces of litchi leaves (removed from the plants approximate to 24 h earlier) were sprayed under a Potter tower and immediately transferred to the 2.5-cm-diameter petri dishes. After 2, 12, 24, and 48 h of the application, the dishes were examined to evaluate the mite survival. The four pesticides causing the highest levels A. litchii mortality, as well as azadirachtin, were tested for the effect on P. intermedius. For this test, experimental units consisted of discs of uninfested litchi leaves also sprayed under a Potter tower before introducing the predators. Survival and oviposition of the predator were evaluated every 24 h for 5 consecutive days; viability of the eggs laid was also evaluated. Highest mortality of A. litchii occurred with the application of fenpyroximate, sulfur, abamectin, and hexythiazox. Azadirachtin was considered moderately harmful to the predator P. intermedius, whereas other pesticides were classified as harmful. Despite the low efficiency of azadirachtin in the control of the pest, its relative selectivity to P. intermedius would encourage the evaluation on field condition, especially for use in organic production systems.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Agronomia (Horticultura) - FCA