Chemical and biological treatments of castor bean seeds: effects on germination, emergence and associated microorganisms

Abstract

RESUMO -Avaliou-se o efeito dos tratamentos químicos e biológicos sobre a emergência, vigor de plântulas de mamona, produção de matéria seca, além do controle de microrganismos associados às sementes das cultivares AL Guarany 2002 e Lyra. Os produtos testados foram carbendazim+thiram, carboxin+thiram e um à base de Trichoderma. A emergência total e de plântulas foram avaliadas aos 27 dias após a semeadura e a produção de matéria seca, com plantas retiradas 45 dias após a semeadura. A cv. AL Guarany 2002 apresentou maior incidência de microrganismos em relação à cv. Lyra. O tratamento químico foi 100% eficiente no controle de fungos e o tratamento biológico não reduziu a incidência de microrganismos nas sementes. O tratamento químico resultou em plantas com maior matéria seca e os melhores resultados foram para carbendazim + thiram e carboxin+ thiram, nas doses de 60 g + 140 g e 50 g + 50 g/100 kg de sementes, respectivamente. O carbendazim + thiram foi o único tratamento que se mostrou estatisticamente superior, quanto ao índice de emergência total, enquanto que o tratamento biológico aumentou os valores de emergência somente na cv. Lyra, evidenciando sua inferioridade. Destacou-se a importância dos fungicidas para o controle de patógenos associados às sementes.Termos para indexação: Ricinus communis, fungicidas, teste de papel filtro, Trichoderma.ABSTRACT -The effect of chemical and biological treatments on castor bean emergence, seedling vigor, dry matter production, and also the control of microorganisms associated with seeds of the AL Guarany 2002 and Lyra cultivars, was evaluated. The products tested were carbendazim + thiram, carboxin + thiram and a product based on Trichoderma. Total seed and seedling emergence were evaluated at 27 days after sowing whereas dry matter production was verified for plants removed 45 days after sowing. The Guarany 2002 AL cultivar had a higher incidence of microorganisms than the Lyra cultivar. The chemical treatment was 100% effective in controlling fungi but the biological treatment did not reduce microorganism incidence on the seeds. Chemical treatment resulted in plants with more dry matter and the best results were for carbendazim + thiram and carboxin + thiram at doses of 60 g + 140 g and 50 g + 50 g/100 kg of seeds, respectively. The carbendazim + thiram mixture was the only treatment which was statistically higher for total emergence whereas the biological treatment increased emergence only for the Lyra cultivar, thus demonstrating its lower efficiency. The importance of fungicides to control pathogens associated with seeds was discussed.

Physiological and Sanitary Quality of Wheat Cultivars Seeds Subjected to Chemical and Biological Seed Treatments

“…The EVI indicates the speed of stabilization of seedling emergence in the field, and the higher the EVI, the faster the stabilization of the seedling stand. It was found that there was no significant difference for the treatments used, corroborating Tropaldi et al (2010) and Marroni et al (2012), who observed in castor oil plant seeds, that among the treatments used, there was no significant differentiation in the EVI. However, it is noted that numerically the fastest stabilization of emergence occurred with the chemical treatment (44.77), and the slowest occurred with the biological treatment (38.72).…”

Tratamentos alternativos para conservação de sementes de mamona (Ricinus communis L.)

“…Analisando os tratamentos com produtos químicos e alternativos, dentro dos períodos de armazenamento estudados, verifica-se que o derosal e o vitavax-thiram apresentaram efeito positivo e superior aos demais produtos na germinação e no vigor das sementes, aos oito e 12 meses (Tabela 1). Os resultados corroboram com aqueles obtidos por Marroni et al (17) e Tropaldi et al (20), que verificaram efeito positivo do vitavax-thiram na porcentagem de germinação de sementes de mamona. Dos produtos alternativos testados, aos quatro meses de armazenamento, o sorbato, o trichodermil, o alecrim e o alho proporcionaram às sementes germinação acima de 90% e superior àquela das sementes não tratadas (testemunha).…”

New Technique to Create a Suspension Containing Bacteriophages and How It Can Be Used to Control Cabbage Leaf Spot Caused by <i>Xanthomonas campestris</i> PV. <i>campestris</i>

“…Disease severity scale of cabbage leaves submitted to different treatments: (1) no symptoms, (2) mild symptoms such as necrosis in the cut area, and few small yellow spots, (3) severe symptoms, such as overall leaf chlorosis, important necrosis in the cut area. To prepare an index of plant disease severity, we used the alternative formula proposed by Marroni et al [18], Σni(1~3)/5, where n is the number of seedlings and i is the index of symptom severity shown by the plants as follows: 1 no symptoms; 2 mild symptoms such as necrosis in the cut area and few small yellow spots; 3 severe symptoms of strong necrosis in the cut area and leaf chlorosis, 5 is number of lesions per plant. It is important to note that the higher the index, the higher the disease severity, and that we made one lesion per leaf.…”