Efficacy of moderate heat against all stages of the tobacco beetle Lasioderma serricorne at controlled humidity

In laboratory experiments, temperatures of 43 °C were tested against all developmental stages and adults of the tobacco beetle at a relative humidity (r h) of 53 % and 61.5 %, respectively. Temperatures of 46 °C have so far been tested just at 53 % r h. At 43 °C and 53 % r h, eggs where the most sensitive, followed by young larval stages with no survivors found after 60 h exposure time. Pupae and elder larvae were the most tolerant, some 96 h lead to complete control in all stages. The higher relative humidity of 61.5% lead to increased mortality at 43 °C, which is attributed to reduced evaporation cooling. Complete control was achieved after approximately 60 h. Thus, possibly heat was more important than desiccation as cause of mortality in this experimental setting. At 46 °C, almost complete mortality of all stages was achieved within 24 h exposure time, no survivors were found after 36 h and 53 % r h.