Data/hora: 09/06/2024 15:53:32

Provedor de dados: | Brazilian Journal of Microbiology
País: | Brazil
Título: | Field persistence of Bacillus thuringiensis on maize leaves (Zea mays L.)
Autores: | Haddad,Marinéia de Lara; Polanczyk,Ricardo Antonio; Alves,Sergio Batista; Garcia,Marcelo de Oliveira.
Data: | 2005-12-01
Ano: | 2005
Palavras-chave: | Entomopathogen; Dipel; Maize leaves; Bacillus thuringiensis; Field persistence.
Resumo: | The persistence slope of Bacillus thuringiensis (Bt) based products in the field is an important parameter to evaluate their efficacy. The half-life, estimated based on persistence slope parameters, is one of the most effective tools to select microbial pesticides. The aim of this research was to study the relationship between viability loss of Bt spores on maize leaves and their concentration, comparing it with field persistence. The experimental design was split-plot on time, composed by maize plants, in which three concentrations (half, normal and double doses) of a Dipel commercial formulation were applied. In each plot three leaves in the upper part of three plants where randomly selected. Samples of these leaves were collected 3 to 72 hours after treatment, to count the number of viable spores in two foliar dishes with 1 cm in diameter. The field persistence was determined using an exponential model, linearized by a logarithmic transformation of viable spores number in time. Using the log linear method of confidence intervals, there were no significantly differences (P = 0.05) in half-lifes: 18.2 hours for half-dose, 16.5 hours for normal dose and 13.6 hours for double dose. Assuming a fictitious index of insect consumption equal to one, the effective doses according to concentrations were calculated. It was verified that 77%, 78% and 80.5% of the effective doses (viable spores) remained on the leaf surface after the first day of treatment, respectively.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822005000400001
Editor: | Sociedade Brasileira de Microbiologia
Relação: | 10.1590/S1517-83822005000400001
Formato: | text/html
Fonte: | Brazilian Journal of Microbiology  v.36 n.4 2005
Fonte: | info:eu-repo/semantics/openAccess