Population dynamics of Thaumastocoris peregrinus in Eucalyptus plantations of South Africa

Abstract

Thaumastocoris peregrinus is a sap sucking insect that infests non-native Eucalyptus plantations in Africa, New Zealand, South America and parts of Southern Europe, in addition to street trees in parts of its native range of Australia. In South Africa, pronounced fluctuations in the population densities have been observed. To characterise spatiotemporal variability in T. peregrinus abundance and the factors that might influence it, we monitored adult population densities at six sites in the main eucalypt growing regions of South Africa.At each site twenty yellow sticky traps were monitored weekly for 30 months, together with climatic data. We also characterised the influence of temperature on growth and survival experimentally, and used this to model how temperature may influence population dynamics.T. peregrinus was present throughout the year at all sites, with annual site specific peaks in abundance. Peaks occurred during Autumn (February -April) for the Pretoria site, Summer (November -January) for the Zululand site and Spring (August -October) for the Tzaneen, Sabie and Piet Retief monitoring sites. Temperature (both experimental and field collected), humidity and rainfall were mostly weakly, or not at all, associated with population fluctuations. It is clear that a complex interaction of these and other factors (e.g. host quality) influence population fluctuations in an annual, site specific cycle. The results obtained not only provide insights into the biology of T. peregrinus, but will also be important for future planning of monitoring and control programs using semiochemicals, chemical insecticides or biological control agents.

Entomopathogenic fungi naturally infecting the eucalypt bronze bug,Thaumastocoris peregrinus(Heteroptera: Thaumastocoridae), in Uruguay

“…Nadel et al (), in their work on population dynamics of T. peregrinus, found that the temperature range tolerated by this insect was between 4 and 39°C, being 30°C the optimum for egg development. Most of the isolates exhibited high spore viability at 30°C.…”

“…isolates, those were selected to assess viability at different temperatures and water activity, as these parameters can correlate with suitability for field applications in suboptimal conditions. Nadel et al (2015), in their work on population dynamics of T. peregrinus, found that the temperature range tolerated by this insect was between 4 and 39°C, being 30°C the optimum for egg development. Most of the isolates exhibited high spore viability at 30°C.…”

The potential global distribution of the Bronze bug Thaumastocoris peregrinusCarpintero and Dellapé (Hemiptera: Thaumastocoridae)

“…These results may explain the population outbreaks that occur during the hot summer season. The maximum critical thermal range for T. peregrinus adults was identified as between 32 and 45 °C by Nadel et al () who reported a mean maximum critical thermal value of 38.6 ± 4.7 °C. Our results showed that high temperatures became limiting at some point between 30 and 35 °C, although the methodology used in the present study was quite different from that in Nadel et al ().…”

“…and hybrids in Brazil, where the effect of host species on the life cycle and reproduction of T. peregrinus was demonstrated. More recently, Nadel et al () conducted a study on the population dynamics of this pest in Eucalyptus plantations of South Africa, as well as laboratory experiments aiming to determine the influence of temperature on growth and survival.…”

Toxicity and repellency of plant extracts on Thaumastocoris Peregrinus (Carpintero Dellap) (Hemiptera: Thaumastocoridae)

“…It has a short life cycle (an average of 35 days) and the female can lay up to 60 eggs during her lifespan (Jacobs and Neser, 2005;Noack and Rose, 2007;Soliman et al, 2012). This high biotic potential enables T. peregrinus to have several generations per year, and to have the potential to spread and rapidly establish into new environments (Nadel et al, 2015;Saavedra et al, 2015).…”