Data/hora: 21/06/2024 08:22:09

Biblioteca(s): | Embrapa Meio Ambiente.
Data corrente: | 11/10/1995
Data da última atualização: | 31/05/2017
Autoria: | PARRA, J. R. P.; SA, L. A. N. de.
Afiliação: | ESALQ/USP; LUIZ ALEXANDRE NOGUEIRA DE SA, CNPMA.
Título: | Biological control of Helicoverpa zea (Boddie) in field and sweet corn through Trichogramma pretiosum Riley in the State of São Paulo, Brazil.
Ano de publicação: | 1995
Fonte/Imprenta: | In: INTERNATIONAL PLANT PROTECTION CONGRESS, 13., 1995, The Hague. Resumos. The Hague: Kluwer Academic, 1995.
Páginas: | n.p.
Idioma: | Inglês
Conteúdo: | It is very common to observe a very high natural parasitism of the corn earworm Helicoverpa zea, by Trichogramma pretiosum under field conditions, in the State of Sao Paulo, Brazil. The parasitism is always superior to 50% and very often reachs levels of 95% in field corn. However, this high level of parasitism is observed only in the last generation of the pest, when the damage has already accurred. The inundative release of T. pretiosum, reared on a factitious host (Anagasta kuehniella), may be an alternative method to control the corn earwom. In this method, releases can be done at the beginning of the corn earworm oviposition period, which occurs at the onset of the corn silking stage. For the "Agrocica Super Doce" sweet corn variety, it was observed that the oviposition peak of H. zea coincides with the blooming stage of the corn. The population dynamics of the corn earworm eggs was correlated with the corn phenology, and we found that the first egg laying occurred 66 days after the germination. We observed that the H. zea biological control through T. pretiosum is possible, if we consider some aspects such as: selection of the most effective T. pretiosum atrain and three releases of T. pretiosum in a 4 day interval, with the first release when 35% of the plants is at silking stage and 75% of the male inflorescence has appeared. The parasitoid release resulted in an increase of parasitization and reduction of the H. zea damage up to 27% in corn ears. For field corn (dent corn variety C555) in two counties of the State of Sao Paulo, the release must also be done at the beginning of the H. zea egg laying. The dispersal capacity of T. pretiosum, 36 hours after release, ranged from 80 to 102m2. The results of this study indicated that releases for controlling the corn earworm should be done in 100 points/ha. For field releasses, it was observed an increase of up to 5 times in parasitism of H. zea eggs when 100,000 T. pretiosum adults/ha were released three times. H. zea damage in corn ears in T. pretiosum released areas was reduced 26%, showing the potential of this parasitoid for the control of the pest. The most agressive strain under laboratory conditions showed parasitism capacity higher in the first four days of the female's life.
Thesagro: | Helicoverpa Zea.
Thesaurus Nal: | biological control.
Categoria do assunto: | --
Registro original: | Embrapa Meio Ambiente (CNPMA)
Exemplares: | CNPMA - (2958-1) - ADD - RA - DD -  -  -  - DIS