Thermal Requirements and Generation Estimates of Trichospilus diatraeae (Hymenoptera: Eulophidae) in Sugarcane Producing Regions of Brazil

Maria Adriana Torqueti Rodrigues, Fabricio Fagundes Pereira, Samir Oliveira Kassab, Patrik Luiz Pastori, Daniele Fabiana Glaeser, Harley Nonato De Oliveira, José Cola Zanuncio

Abstract


Knowledge of the thermal requirements of Trichospilus diatraeae (Hymenoptera: Eulophidae) is important if it is to be used successfully in to control Diatraea saccharalis (Lepidoptera: Crambidae) in sugarcane plantations. In the current study, the development of T. diatraeae was investigated in the pupae of D. saccharalis incubated at different temperatures. Seven T. diatraeae females were placed with host pupae for 24 h in tubes within chambers at 16, 19, 22, 25, 28 and 31 °C with 70 ± 10% RH and 14:10 h L:D. The life cycle duration of T. diatraeae decreased as the temperature increased, although no development was recorded at 31 °C. The number of T. diatraeae progeny per female ranged from 264.8 ± 40.7 (at 16 °C) to 385.1 ± 36.3 (at 25 °C), but no significant difference were recorded among temperature treatments (P > 0.05). The base temperature (Tb) and thermal constant (K) of T. diatraeae were 9.37 °C and 257.60 degree-days, respectively. The estimated average numbers of generations per year of T. diatraeae in pupae of D. saccharalis were 18.5, 19.93 and 17.73 for Dourados, Ivinhema and Ponta Porã municipalities of Mato Grosso do Sul State, Brasil, respectively.

El conocimiento de las exigencias térmicas es importante para el uso de Trichospilus diatraeae (Hymenoptera: Eulophidae) en el control de Diatraea saccharalis (Lepidoptera: Crambidae) en plantaciones de caña de azúcar. Se estudio el desarrollo de T. diatraeae en pupas de D. saccharalis incubadas a diferentes temperaturas. Pupas de D. saccharalis fueron expuestas a siete hembras de T. diatraeae durante 24 h en tubos y luego colocadas en cámaras climatizadas a temperaturas de 16, 19, 22, 25, 28 y 31 °C con 70 ± 10% de humedad relativa y foto-periodo de 14 h. La duración del ciclo de vida de T. diatraeae disminuyó con el aumento de la temperatura. Este parasitoide no completó su desarrollo a 31 °C. La progenie de T. diatraeae varió de 264.75 ± 40.69 (16 °C) a 385.09 ± 36.28 (25 °C) individuos por hembra, sin presentarse diferencias significativas entre los tratamientos (P > 0,05). La temperatura base (Tb) y la constante térmica (K) de T. diatraeae fueron de 9.37 °C y 257.60 grados-día, respectivamente. El número medio estimado de generaciones por año de T. diatraeae en pupas de D. saccharalis fue de 18.5, 19.93 y 17.73 para los municipios brasileños de Dourados, Ivinhema y Ponta Porã, Mato Grosso do Sul, Brasil, respectivamente.

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