Control Of Periplaneta Americana And Blattella Germanica Oothecae Using Chemical And Biological Insecticides

Periplaneta americana and Blattella germanica are pests of great importance in urban areas, mainly due to their role as vectors of pathogens and capability of causing allergies. The interspecific differences between these cockroaches can lead to different results in their control. No chemical (liquid/powder application) or biological products have been successful in controlling pre-embryonic stages of cockroaches and little is known about their residual effect on nymph eclosion. The objective of this study was to analyze the potential of different synthetic chemical insecticides and entomopathogenic fungi in controlling oothecae of P. americana and B. germanica. Two experiments were conducted with the objective of determining nymphal mortality. First, the oothecae of B. germanica and P. americana were submitted to the following treatments: T1 – control, T2 – indoxacarb (0.03g/10mL) T3 –fipronil (62µL/10mL), T4 – lambda cyhalotrin (63µL/10mL) T5 – imidacloprid (31.70µL/10mL) and T6 – imidacloprid + β-cyfluthrin (21µL/10mL); and then the percentage of dead oothecae, the total number of nymphs eclosed and dead nymphs were compared. In the second bioassay, the same variables were analyzed after submitting oothecae to the following treatments: T1 – control, T2 – deltamethrin 0.05% (0.037g/0.015m2), T3 – thyme oil 4.1% (0.046g/0.015m2), T4 –imidacloprid + β-cyfluthrin 0.075% (1.22mL/0,015m2), T5 – isolate 428 of Beauveria bassiana (2.6 x 108 conidia/0.015m2) and T6 – isolate 2575 of Metarhizium anisopliae (1.7 x 108 conidia/0.015m2). Each treatment consisted of 50 oothecae with 5 repetitions. Data were compiled and subjected to analysis of variance by the F test in a factorial (6 treatments X 2 cockroaches) and the means compared by the Tukey test (p≤0.05). M. anisopliae was the most effective strategy to control oothecae of both cockroach species. The chemical active ingredients fipronil, lambda cyhalothrin, deltamethrin and imidacloprid + β-cyfluthrin were most effective in controlling nymphs of these cockroach species.