Ozônio como fumigante na proteção de milho armazenado

• Autor(a) principal: Rozado, Adriano Ferreira
• Data de Publicação: 2005
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3642
• topic: Ozônio; Milho; Sitophilus zeamais; Tribolium castaneum; Ozone; Corn; Sitophilus zeamais; Tribolium castaneum; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA

The current work aimed to assess the susceptibility of adults of Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae) and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), subjected to ozone treatment at different depths in the grain mass, thus estimating the lethal time for 50% and 95% of each species population, and also assess the physiological quality of the maize grains subjected to the ozone treatment. Maize grains with moisture level around 13% (wb) were distributed in cylindrical PVC containers with 20 cm diameter, 100 cm high and connections for gas injection and exhaustion. At 10 cm from the base of the container, a metallic net was placed to sustain the grain and to form a plenum for better gas distribution. Maize grains infested with adults of Sitophilus zeamais and Tribolium castaneum, obtained from laboratory colonies from climatic chamber of the B.O.D. type, were placed in cages of 3.0 cm high and 15.0 cm diameter with top and bottom of voil to evaluate the efficiency of ozone as fumigant. These cages were placed at different grain mass depths (over the plenum, middle and top of grain column) and subjected to a modified atmosphere of 50 ppm ozone under different exposure periods. The ozone was injected in a continuous flow of 8.0 L min-1 in connection located at the base (plenum) of the container. Tests of electrical conductivity, germination potential and humidity level were carried out in the maize grains to assess the ozone effect on them. The grain mass temperature was maintained around 25 oC throughout the experiment. To do that, a temperature controlled chamber was built where the containers were placed. The temperature was monitored through a data acquisition and store system called f-wire. Six cylindrical containers were used in all of the assays and in three of these ozone was injected, while the remaining ones were injected with atmospheric air (control). It was concluded that in general the increase in exposure period increased the efficiency of the treatments with 50 ppm ozone for adults S. zeamais and T. castaneum. The species S. zeamais was more susceptible. The highest exposure period to control 95% of the insects was of 240.75 h for S. zeamais and 390.18 h for T. castaneum. The greatest exposure period to control 50% of the adult insects was 124.20 h for S. zeamais and 234.75 h for T. castaneum. In general, the treatments with modified atmosphere containing 50 ppm ozone and atmospheric air did not affect the physiological quality of the maize grains.