Efeito de casca de camarão, hidrolisado de peixe e quitosana no controle da murcha de Fusarium oxysporum f.sp. chrysanthemi em crisântemo
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Data
2010-02-01
Autores
Pinto, Zayame Vegette [UNESP]
Bettiol, Wagner
Morandi, Marcelo Augusto Boechat
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Fitopatologia
Resumo
O potencial de casca de camarão e hidrolisado de peixe incorporados ao substrato à base de casca de Pinus e da quitosana pulverizada nas plantas foi avaliado para o controle da murcha de Fusarium em crisântemo. A severidade da doença foi avaliada por uma escala de notas de 0 a 5, após 8, 12, 15 e 20 semanas do plantio nos experimentos com casca de camarão e hidrolisado de peixe. No ensaio com quitosana avaliou-se a severidade na 18ª semana após o plantio. O desenvolvimento das plantas e análises químicas e da atividade microbiana dos substratos foram avaliados. A casca de camarão suprimiu a doença e promoveu o crescimento da planta na concentração de 4%, porém na de 5% causou fitotoxicidade. A indução da supressividade pela casca de camarão foi, possivelmente, devido às alterações nas características físico-químicas e biológicas do substrato. Apesar disso, como a concentração ideal para o controle da doença e promoção de crescimento foi próxima da que causou fitotoxicidade, o seu uso deve ser com cautela. O hidrolisado não suprimiu a doença e a severidade foi diretamente proporcional à sua concentração no substrato. A quitosana gerou resultados variáveis, não sendo possível o estabelecimento de uma resposta padrão.
The incorporation of shrimp peelings and fish hydrolyzate into a pine-bark container medium and an aerial spray of chitosan were investigated for the control of Fusarium wilt of chrysanthemum. Disease severity was evaluated by means of a six-category scale (0 - healthy plant to 5 - dead plant) at 8, 12, 15 and 20 weeks after planting in experiments with shrimp peelings and fish hydrolyzate, and after 18 weeks in the chitosan experiment. The total microbial activity of the container media was evaluated (by fluorescein diacetate hydrolysis), physicochemical attributes of the media were assessed, and plant growth components were measured. Incorporation of shrimp peelings into the pine-bark medium at 4% (v/v) suppressed wilt, but at 5% the plants exhibited symptoms of phytotoxicity and died. The suppression of Fusarium wilt was possibly due to physicochemical and biological changes in container medium induced by the shrimp peel. Given that the concentration which was phytotoxic was only slightly higher than the concentration which suppressed wilt and promoted plant growth, caution is needed in any use of shrimp peelings for wilt control. The fish hydrolyzate increased wilt severity as the concentration was increased. No consistent effects were found of chitosan applied to the aerial parts of the plant.
The incorporation of shrimp peelings and fish hydrolyzate into a pine-bark container medium and an aerial spray of chitosan were investigated for the control of Fusarium wilt of chrysanthemum. Disease severity was evaluated by means of a six-category scale (0 - healthy plant to 5 - dead plant) at 8, 12, 15 and 20 weeks after planting in experiments with shrimp peelings and fish hydrolyzate, and after 18 weeks in the chitosan experiment. The total microbial activity of the container media was evaluated (by fluorescein diacetate hydrolysis), physicochemical attributes of the media were assessed, and plant growth components were measured. Incorporation of shrimp peelings into the pine-bark medium at 4% (v/v) suppressed wilt, but at 5% the plants exhibited symptoms of phytotoxicity and died. The suppression of Fusarium wilt was possibly due to physicochemical and biological changes in container medium induced by the shrimp peel. Given that the concentration which was phytotoxic was only slightly higher than the concentration which suppressed wilt and promoted plant growth, caution is needed in any use of shrimp peelings for wilt control. The fish hydrolyzate increased wilt severity as the concentration was increased. No consistent effects were found of chitosan applied to the aerial parts of the plant.
Descrição
Palavras-chave
Chrysanthemum morifolium, supressividade, substratos, matéria orgânica, patógeno de solo, Chrysanthemum morifolium, suppressiveness, plant growth media, organic residues, soil-borne pathogen
Como citar
Tropical Plant Pathology. Sociedade Brasileira de Fitopatologia, v. 35, n. 1, p. 016-023, 2010.