Parasitismo de Trichospilus diatraeae e Palmistichus elaeisis (Hymenoptera: eulophidae) em pupas de Diatraea saccharalis (Lepidoptera: crambidae)

Abstract

Knowledge of biological and behavioral aspects constitute basic information for studies such as the selection of parasitoid species with potential for pest control. The objective was to compare the biological aspects of reproductive T. diatraeae and P. elaeisis reared on pupae of D. saccharalis and skills to locate and parasitize pest pupae inside stems of cane sugar. Thirty-six pupae of D. saccharalis were individualized in glass tubes (2.5 x 8.5 cm) and distributed in three treatments represented by exposure to parasitoids by a female of P. elaeisis or a female of T. diatraeae or a female of P. elaeisis + one female of T. diatraeae. After 24 h the parasitoids were removed from the tubes and pupae kept at 25 ° C, 70% relative humidity and 14 h photoperiod until emergence of parasitoids. The highest rate of parasitism and emergence was for P. elaeisis. When these two species were put together to parasitize the pupae, there was only the emergence of P. elaeisis, considered the dominant species parasitize pupae of D. saccharalis inside glass tubes. To analyze the ability to search and parasitism were used seventy-five stalks of cane-sugar 10 to 15 cm and made a hole in each stem, which was introduced a pupa of D. saccharalis 24 hours old. After fixation of the pupae, each stem was inserted into transparent plastic bottles. These cylinders were released 21 females of P. elaeisis or 21 females of T. diatraeae or even 21 females of P. elaeisis + 21 females of T. diatraeae as treatments. 72 hours after the pupae were removed from the interior of the stalks in separate glass tubes at 25 ° C, 70% relative humidity and 14 h photoperiod until emergence of parasitoids. The highest rate of parasitism and emergence was T. diatraeae and no emergence of P. elaeisis. Parasitism was not observed when the parasitoids were released together. Trichospilus diatraeae showed greater efficiency in parasitizing and developing in pupae of D. saccharalis inserted inside culms of cane sugar.