Storage conditions’ effects on two Bemisia tabaci parasitoids’ (Eretmocerus mundus and Encarsia sophia) emergence
Ali Ben Belgacem, Mohamed Sadok Bel-Kadhi and Refki Ettaieb
The storage conditions of pests’ natural enemies are prominent factors that delineate the biological control technique applicability and its effectiveness. In this work we evaluated two indigenous Bemisia tabaci’ parasitoids Eretmocerus mundus and Encarsia Sophia emergences following short -terms storage at temperature ranging from 0 to 12 °C. To do so, we used E. mundus and E. Sophia pre-pupae that were submitted to one combination of the following conditions: constant temperature of 0, 2, 4, 6, 8, 10 or 12 °C and duration of 5, 10, 15, 20, 25 or 30 days. Our results showed that the two wasps’ emergence rate significantly increases when temperature is hissed, but it drops down when storage duration is longer. The optimal emergence rate were observed when storage conditions were set at 10 – 12 °C for 5 to 10 days, both for E. mundus (from 93 ± 4.83 to 98 ± 4.22%) and E. Sophia (from 81 ± 9.94 to 95 ± 7.07%). The evaluation of time lapses to emergence arrest and its maximal value permitted to define the chronology of 2nd release of parasitoids that might be applied 7 days after the first one, in the geothermal greenhouses. It is concluded that 10 to 12 °C temperature and duration of 5 to 10 days are optimal conditions to conserve the E. mundus and E. Sophia pre-pupae, in order to allow a maximal rate of their emergence. Further studies are in need to better explore these findings to ameliorate the two wasps’ use in managing B. tabaci pest.