Resposta de clones de Eucalyptus ao ataque da microvespa-da-galha Leptocybe invasa

Abstract

The eucalyptus gall wasp (Leptocybe invasa) is a pest that causes serious damage in young plantations and seedlings of eucalypt. However, there is still no method of control to combat this pest. Therefore, there is a challenge to develop plant materials that can offer higher degrees of resistance to this pest. Thus, this study aimed to determine the response of different Eucalyptus clones exposed to the attack of eucalyptus gall wasp. In order to undertake the study clones of eucalyptus were divided in two subgroups: exposed plants and unexposed plants. The results showed that the attack of eucalyptus gall wasp affected growth in height and collar diameter in all clones evaluated in comparison with the average growth of unexposed plants. In terms of absolute values there was a higher effect of parasitism on growth in percentage in the height variable than in collar diameter. Regression curves determined that all clones were susceptible to the attack of eucalyptus gall wasp. The quality of infested plants showed low levels of robustness being adequate to sturdiness quotient. The visual symptoms associated with parasitism were observed in all clones, presenting different average numbers of presence of oviposition symptoms for clone. The development of galls was confirmed in all infested plants, presenting no statistical difference between the values analyzed although the higher number of galls was registered in Eucalyptus urophylla and Eucalyptus urograndis than in Eucalyptus urocam. These results show the pest behavior in response to different commercial plant materials studied. Thus, this study can contribute to determine future methods to control L.invasa.