Toxicity assessment of plant extracts to Cleruchoides noackae Lin and Huber (Hymenoptera: Mymaridae)

摘要

Extracts of Matricaria chamomilla, Maytenus ilicifolia and Echinodorus grandiflorus have been integrated as viable pest management strategy for controlling bronze bug Thaumastocoris peregrinus (Hemipetra: Thaumastocoridae) due to their insecticidal activities. However, the side effects of these extracts on Cleruchoides noackae (Hymenoptera: Mymaridae), the main biological control agent against the bronze bug of eucalyptus, have never been studied. The objective of this study was to verify the effect of 5% aqueous extracts of M. chamomilla, M. ilicifolia and E. grandiflorus on C. noackae. Tests with eggs treated before being offered to the parasitoid female (pre-parasitism) and tests on which the eggs were treated 1 and 7days after the female had performed oviposition (post-parasitism) were carried out. There was no difference between the treatments and the control group regarding parasitoid emergence in none of the tests. Although, there was increase in egg viability and number of emerged parasitoids when comparing the eggs treated 1 and 7days after parasitism for all treatments. In conclusion, none of the plant extracts caused any harmful effect on C. noackae under lab conditions, indicating they may be an environment-friendly option to control the bronze bug of eucalyptus.