Valutazione in vivo dell’efficacia di nuovi sinergici abbinati ad insetticidi nei confronti di Blattella germanica (L.)

[Autom. eng. transl.] One of the most widespread insect pests in the global anthropic environment is Blattella germanica (L.). Thanks to the ease with which it colonizes homes, commercial kitchens, laundries, etc., it is one of the most relevant insects from a hygienic-sanitary point of view, as its involvement in the transmission of numerous species of pathogens is well known, in addition to the potential allergens for humans . In B. germanica the resistance to insecticides has been growing over the years and has become one of the major obstacles to implementing efficient control strategies for this pest. Currently the insecticidal baits with gel formulation maintain a good efficacy while the conventional treatments involving the use of spray formulations, above all of pyrethroids, have shown many limits. In the literature there are numerous cases of ineffectiveness for various active ingredients against B. germanica, making it the second most resistant urban insect in the world ranking. A possible solution to this problem may come from the use of synergists such as piperonyl butoxide (PBO), molecules without or with negligible insecticidal activity which when applied in combination with various insecticidal products enhance its efficacy by inhibiting the metabolic detoxification systems present in the target insect. In this study, performed as part of the European project "Ecosyn" (EcoSyn -Ecofriendly synergists for insecticide formulations, funded by the Seventh Framework Program of the European Union - Contract no. 605740), the PBO and some of its new derivatives were combined with insecticides of already known efficacy, such as cypermethrin and S-metoprene, to evaluate the possible synergistic effect. For the tests with the pyrethroid a contact test was developed, treating glass containers with a mixture of insecticide dissolved in a solution of synergist in acetone and leaving the insects in contact with the treated surface for 30 minutes and then evaluating the knock effect. -down every 5 minutes. Subsequently the insects were transferred to untreated containers, supplying them with water and food. Mortality was assessed after 24 hours. In general the various synergists did not increase the knock-down effect but caused a significant increase in mortality compared to the insecticide used alone. Only one of the new derivatives showed, when used alone, limited toxicity against B. germanica. The experiment with S-metoprene was carried out by administering only wet females containing insecticide and synergistic for a week. After mating with untreated males, both mortality and the appearance, abortion or hatching of the ootheca were measured every day. The data, albeit with differences between the various synergists, show that the cockroaches treated, with respect to the control ones, have a delay in the formation of the wine shops, an increase in the percentage of abortion of the same and a reduction in the number of births.