The quality of the seeds used for sowing is fundamental for a high productivity and quality of the crop. Therefore, eradicating pathogens is essential for the plant to develop in the best possible way. The eradication of those pathogens can be accomplished by means of treatments that consist of the application of substances to the seeds or by performing physical procedures. Thermotherapy is a physical treatment, in which the seed is exposed to a given thermal energy, such as heated air or steam, and can be highly efficient for controlling those pathogens, in addition to reducing environmental damage and costs. The present work aimed to evaluate the efficiency of thermotherapy in two ways: wet heat (water) and dry heat (water vapor), both at 60 °C, alternating the exposure time to the thermal sources. The treatment with humid heat with a time of exposure of 5 min was the most efficient, since it presented higher germination percentages (83%) and less occurrence of Fusarium sp. (33%). It was observed that the most efficient thermotherapy is in the control of Fusarium, the most aggressive is for the quality of the seed. The quality of the treatments was evaluated through standard methodologies, according to the rules for seed analysis, such as germination and sanitation tests. Biospeckle laser was used to identify the microbial activity in these seeds, through activity maps generated by laser speckle contrast analysis (LASCA) processing. In this way, the research involving thermotherapy can be done by varying the temperature and the time of exposure to obtain values that considerably reduce the pathogenic agents and preserve the quality, in order to maintain the values of germination and vigor acceptable for commercialization.

R ESU M OObjetivou-se, com o presente trabalho, avaliar e comparar o desempenho de três estratégias de aeração de milho armazenado quanto à ocorrência de fungos e à condutividade elétrica dos grãos. As estratégias avaliadas foram: aeração contínua; aeração noturna e aeração em condições de umidade de equilíbrio entre os grãos e o ar ambiente. Realizaram-se dois ensaios de aeração com grãos de milho secos (11% b.u.) e úmidos (17% b.u.). Amostras de grãos foram retiradas durante os ensaios para contagem de fungos e medida da condutividade elétrica dos grãos. Grãos armazenados úmidos apresentaram maior ocorrência de fungos do que grãos armazenados secos. Observou-se que o Fusarium spp. apresentou contagens mais elevadas, o Penicillium spp. manifestou desenvolvimento e o Aspergillus spp. ocorreu com menor frequência. As estratégias de aeração empregadas não interferiram na condutividade elétrica dos grãos de milho armazenados, visto que não houve diferença significativa dos valores de condutividade elétrica entre os grãos submetidos a aeração e os grãos armazenados sem aeração.Palavras-chave: armazenamento, Aspergillus spp., Penicillium spp., Fusarium spp. Performance of aeration strategies for stored corn:Molds and electrical conductivity A B ST R A C T The aim of this study was to evaluate and to compare the performance of three aeration strategies for stored corn as for occurrence of molds and electrical conductivity of grain: continuous aeration; night aeration and aeration under equilibrium moisture content conditions between the grains and the ambient air. Two tests of aeration with dry corn grain (11% w.b.) and wet corn (17% w.b.) were done. Grain samples were taken during testing for counting of molds and measuring of electrical conductivity of grains. Wet corn stored had increased incidence of molds more than dry corn stored. It was observed that the Fusarium spp. showed higher scores, Penicillium spp. showed development and Aspergillus spp. occurred with lesser frequency. Aeration strategies employed did not affect the electrical conductivity of corn stored because there was no significant difference in electrical conductivity values between the aerated grain and non-aerated grains.

Abstract:The present work aimed to study the treatment with the bioprotector Trichoderma harzianum on maize seeds immediately after treatment and during storage. Maize seeds were analyzed through germination test, vigor tests (cold test, accelerated aging and aerial length), and the viability of the treated seeds was verified through the biospeckle. Seed treatment is recommended because approximately 90% of crops intended for human and animal feeding are seed-propagated. A pathogen present in the seed results in increased diseases in the adult plant, in addition to introducing pathogens in other areas. So the seed treatment can provide better results than chemicals disease control on plants. Bioprotectors have antagonistic fungi that produce metabolites and enzymes that will avoid the proliferation of phytopathogenic fungi. Among the bioprotectors, Trichoderma spp., used for phytosanitary control of seeds, stands out. The tests were carried out with treatment in order to evaluate the physiological potential caused by the treatment with the bioprotector. The biospeckle experimental runs were performed in parallel with the sanitation test. The germination percentages of 93.0%, 87.5%, and 87.5%, respectively, showed that they were all above the minimum requirement for commercialization, which is 85%. Analyzing the vigor and sanitation tests, it was verified that the best treatment was on day zero. Among the seeds analyzed through biospeckle, using the laser speckle contrast analysis (LASCA) technique, it was possible to identify fungi activity.

RESUMOA produção agrícola no Brasil tem aumentado devido à crescente demanda por alimentos, gerando grandes quantidades de resíduos agrícolas, necessitando práticas de reciclagem para diminuir os débitos econômicos e ambientais causados. O objetivo do estudo proposto foi avaliar fertilizantes de liberação lenta (F1 e F2) produzidos a partir de bio-óleo. Para isso, bio-óleo produzido de serragem foi submetido a reações termoquímica com (NH 2 ) 2 CO (F1) e bio-óleo com NH 4 OH mais biocarvão (F2). O crescimento do hipocótilo de plântulas de milho foi monitorado com adição de F1 em areia nas doses 1,2, 2,4, 4,0, 8,0, 16,0, 24,0, 32,0 e 40,0 t ha -1 e as mesmas doses para F2, além da testemunha. Ambos os fertilizantes são fontes de nitrogênio e potássio para nutrição das plantas. No entanto, F2 apresentou melhor desenvolvimento das plântulas de milho quando comparado com o F1.Palavras-Chaves: LIBERAÇÃO LENTA, BIOMASSA, PIRÓLISE.