Thermal requirements and estimate number of generations of Palmistichus elaeisis (Hymenoptera: Eulophidae) in different Eucalyptus plantations regions

Abstract

To use Palmistichus elaeisis Delvare and LaSalle, 1993 (Hymenoptera: Eulophidae) in a biological control programme of Thyrinteina arnobia (Stoll, 1782) (Lepidoptera: Geometridae), it is necessary to study thermal requirements, because temperature can affect the metabolism and bioecological aspects. The objective was to determine the thermal requirements and estimate the number of generations of P. elaeisis in different Eucalyptus plantations regions. After 24 hours in contact with the parasitoid, the pupae was placed in 16, 19, 22, 25, 28 and 31 °C, 70 ± 10% of relative humidity and 14 hours of photophase. The duration of the life cycle of P. elaeisis was reduced with the increase in the temperature. At 31 °C the parasitoid could not finish the cycle in T. arnobia pupae. The emergence of P. elaeisis was not affected by the temperature, except at 31 °C. The number of individuals was between six and 1238 per pupae, being higher at 16 °C. The thermal threshold of development (Tb) and the thermal constant (K) of this parasitoid were 3.92 °C and 478.85 degree-days (GD), respectively, allowing for the completion of 14.98 generations per year in Linhares, Espírito Santo State, 13.87 in Pompéu and 11.75 in Viçosa, Minas Gerais State and 14.10 in Dourados, Mato Grosso do Sul State.

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

“…This could be used to synchronize parasitoid emergence with the presence of its host at the right stage in the field to improve the efficiency of the mass rearing and release of this natural enemy in biological control programs (Sagarra et al 2000;Krugner et al 2007;Bueno et al 2008). Thermal requirements allow calculation of the time needed to complete the development of both a pest and its natural enemies (Zanuncio et al 2004;Pereira et al 2011). The thermal requirements of T. diatraeae in the laboratory were similar to those of D. saccharalis (T b = 8.0 °C and K = 371.88 DD) (Paron & Berti-Filho 2000).…”

“…However, this parasitoid showed a shorter development cycle compared with D. saccharalis and, therefore, a higher number of generations. This might help reduce or stabilize the population density of D. saccharalis at a low level in the field Pereira et al 2011).…”

“…However, little is known about this parasitoid, including its temperature range. The relation between environmental temperature and insect development can be used to determine the best conditions to rear insects that will be released in the field and to predict the number of generations of the pest and its natural enemies (Nava et al 2007;Wanderley et al 2007;Pereira et al 2011).Temperatures above or below an optimal value can affect insect development (Rodrigues et al 2004). Determining the optimum temperature can allow production of a large number of individuals with adequate survival, and with high reproductive and parasitism rates, both in laboratory and in the field (Medeiros et al 2004;Pereira et al 2004;Pratissoli et al 2006;Zago et al 2006;Pasini et al 2010).…”

PLANTAS HOSPEDEIRAS DE Thyrinteina arnobia (LEPIDOPTERA: GEOMETRIDAE) AFETAM O DESENVOLVIMENTO DO PARASITOIDE Palmistichus elaeisis (HYMENOPTERA: EULOPHIDAE)1

“…Além disso, essa forma de controle provoca a redução da população de inimigos naturais, contaminação ambiental, aumento dos custos de produção e resistência de pragas (PEREIRA et al, 2011). Por isso, métodos complementares têm sido propostos, compondo o Manejo Integrado de Pragas (MIP).…”

“…Parasitoides são inimigos naturais de grande importância para o equilíbrio do agroecossistema de eucalipto (PEREIRA et al, 2011). Palmistichus elaeisis Delvare e La Salle (Hymenoptera: Eulophidae) é um endoparasitoide de pupas generalista e com alto potencial para o controle biológico de lepidópteros na eucaliptocultura (PEREIRA et al, 2009).…”