Controle biológico da podridão radicular (Pythium aphanidermatum) em cultivos hidropônicos
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Data
2009-12-17
Autores
Corrêa, Élida Barbosa [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O cultivo hidropônico de hortaliças vem crescendo e se tecnificando no Brasil. No entanto, podridões radiculares causadas por espécies de Pythium constituem um sério problema para a sua expansão. Uma vez o patógeno instalado no sistema, esse pode ser suprimido por meio da adição de microrganismos antagônicos. Além de suprimirem a podridão radicular, esses microrganismos introduzidos na solução nutritiva podem promover o crescimento das plantas, aumentando a receita do produtor. Entretanto, muitas vezes verifica-se baixa sobrevivência dos microrganismos adicionados na solução nutritiva. O desenvolvimento de formulações de agentes de controle biológico, principalmente de bactérias do gênero Pseudomonas, é um fator chave para a sua utilização em escala comercial. Devido à importância da podridão radicular em cultivos hidropônicos e o potencial de utilização do controle biológico da doença, os objetivos do presente trabalho foram (i) selecionar microrganismos residentes do manguezal como agentes de biocontrole da podridão radicular e promotores de crescimento em pepino hidropônico; (ii) avaliar o controle biológico da podridão radicular e a promoção de crescimento por Pseudomonas chlororaphis 63-28 e Bacillus subtilis GB03 em pimentão e alface cultivados em hidroponia; (iii) desenvolver uma formulação de Pseudomonas spp.. Em condições de casa de vegetação, Bacillus cereus AVIC-3-6, isolado de manguezal, protegeu as plantas de pepino do subdesenvolvimento causado pelo patógeno; Gordonia rubripertincta SO-3B-2 e Pseudomonas stutzeri MB-P3A-49, também isolados de manguezal, promoveram o crescimento de plantas de pepino não inoculadas com o patógeno. A adição de P. chlororaphis 63-28 e B. subtilis GB03 na solução nutritiva de pimentão cultivado em hidroponia e inoculado com P. aphanidermatum teve efeito positivo na supressão dos danos causados...
Hydroponic production of vegetables and flowers is increasing in Brazil, and the production technology is improving. A major factor constraining crop productivity is root rot caused by Pythium spp. Root rot severity can be reduced by the application of appropriate antagonistic microbes into the hydroponic nutrient solution or root zone of the crops. When in the root zone beneficial microbes may suppress progress of the root rot and increase crop productivity. However some beneficial microbes are not well-adapted to hydroponic environments and do not survive well in plant nutrient solutions. Ecologically-adapted microbes that are effective against root rot are a key factor for successful root rot control in hydroponic crops. The need for effective biological agents that are adapted to hydroponic systems and appropriately formulated for commercial use prompted investigations with the following aims: i) to select bacterial strains from among isolates obtained from mangrove swamps for effectiveness in controlling Pythium root rot in hydroponic cucumber; ii) to evaluate Pseudomonas chlororaphis 63-28 and Bacillus subtilis GB03 for controlling root rot and promoting growth of hydroponic lettuce and pepper; and iii) to assess formulations of Pseudomonas spp. for long-term shelf life. Bacillus cereus AVIC -3-6 from a mangrove reduced stunting of hydroponic cucumbers associated with Pythium root rot. Gordonia rubripertincta SO-3B-2 and Pseudomonas stutzeri MB-3PA-49 from a mangrove increased growth of healthy cucumber plants. Application of Pseudomonas chlororaphis 63-28 and Bacillus subtilis GB03 into the nutrient solution of hydroponic pepper suppressed root rot and increase the plant growth. Among tested formulations of Pseudomonas chlororaphis 63-28, a formulation with coconut fibre of 80% moisture content had the longest shelf life (up to 32 weeks) when kept at at 3ºC. We conclude that a)... (Complete abstract click electronic access below)
Hydroponic production of vegetables and flowers is increasing in Brazil, and the production technology is improving. A major factor constraining crop productivity is root rot caused by Pythium spp. Root rot severity can be reduced by the application of appropriate antagonistic microbes into the hydroponic nutrient solution or root zone of the crops. When in the root zone beneficial microbes may suppress progress of the root rot and increase crop productivity. However some beneficial microbes are not well-adapted to hydroponic environments and do not survive well in plant nutrient solutions. Ecologically-adapted microbes that are effective against root rot are a key factor for successful root rot control in hydroponic crops. The need for effective biological agents that are adapted to hydroponic systems and appropriately formulated for commercial use prompted investigations with the following aims: i) to select bacterial strains from among isolates obtained from mangrove swamps for effectiveness in controlling Pythium root rot in hydroponic cucumber; ii) to evaluate Pseudomonas chlororaphis 63-28 and Bacillus subtilis GB03 for controlling root rot and promoting growth of hydroponic lettuce and pepper; and iii) to assess formulations of Pseudomonas spp. for long-term shelf life. Bacillus cereus AVIC -3-6 from a mangrove reduced stunting of hydroponic cucumbers associated with Pythium root rot. Gordonia rubripertincta SO-3B-2 and Pseudomonas stutzeri MB-3PA-49 from a mangrove increased growth of healthy cucumber plants. Application of Pseudomonas chlororaphis 63-28 and Bacillus subtilis GB03 into the nutrient solution of hydroponic pepper suppressed root rot and increase the plant growth. Among tested formulations of Pseudomonas chlororaphis 63-28, a formulation with coconut fibre of 80% moisture content had the longest shelf life (up to 32 weeks) when kept at at 3ºC. We conclude that a)... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Hidroponia, Hortaliças - Cultivo, Manguezal, Podridão radicular, Pythium aphanidermatum, Hydroponic crops, Biological control
Como citar
CORRÊA, Élida Barbosa. Controle biológico da podridão radicular (Pythium aphanidermatum) em cultivos hidropônicos. 2009. xii, 93 f. Tese (doutorado) - Universidade Estadual Paulista , Faculdade de Ciências Agronômicas de Botucatu, 2009.