The biology of Trichogramma pretiosum as atmospheric O2 becomes depleted and CO2 accumulates

This study evaluated the effect of modified atmospheric concentrations of O2 and CO2 on the biology of Trichogramma pretiosum Riley. For this purpose, cards with five different quantities of parasitized eggs were kept in hermetically sealed vials producing five different atmospheres as a function of different parasitoid respiration levels. Controls consisted of egg cards kept in an ambient atmosphere in ventilated vials. Concentrations of O2 and CO2 in vials were measured daily with a gas analyzer. No parasitoids emerged from vials where the CO2 concentration exceeded 16% and O2 was less than 2.5%. Only 47% of T. pretiosum emerged in an atmosphere with a maximum of 13.3% CO2 and 6.78% O2, significantly lower than in treatments with lower CO2 and higher O2 concentrations, or controls. Parasitoid performance was also diminished by high CO2 and low O2 conditions, relative to controls. We conclude that rearing conditions for T. pretiosum should ensure ventilation sufficient to maintain CO2 levels below 4.3% and O2 levels above 18.5%. Graphical abstract

Source: Biological Control - November 11, 2016 Category: Biology Source Type: research