Reproductive and toxicological impacts of herbicides used in Eucalyptus culture in Brazil on the parasitoid Palmistichus elaeisis (Hymenoptera: Eulophidae)

Abstract

The expansion of eucalyptus tree plantations in Brazil has raised concerns that the use of herbicides may reach non‐target organisms and compromise the environment where parasitoids are used to control Lepidoptera defoliators. So, the effect of herbicides used in eucalyptus crops on the parasitoid Palmistichus elaeisis Delvare and LaSalle, 1993 (Hymenoptera: Eulophidae) was evaluated in terms of the impact on reproduction and survival. Treatments consisted of commercial doses of the herbicides sulfentrazone, oxyfluorfen, glyphosate and isoxaflutole with a water‐only control. The herbicides were sprayed on the pupae of the alternative host Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae), which were exposed to parasitism by six females of P. elaeisis per pupa. Glufosinate and oxyfluorfen reduced parasitism and emergence of this parasitoid and were considered more harmful to the P. elaeisis females. Glyphosate and isoxaflutole resulted in higher numbers of individuals and females produced per female; thus these herbicides were less harmful to P. elaeisis and maybe used in IPM programmes in eucalyptus plantations.