Parasitoid Species Associated with Immature Stages <i>pieris rapae</i> (L.) Inhabiting Cabbage Plantations in Assiut Governorate, Upper Egypt

Abstract

This work was initiated for the first time to identify parasitoid species associated with the immature stages of Pieris rapae (L.) inhabiting cabbage plantations in Assiut governorate, Upper Egypt during the 2018 and 2019 cabbage growing seasons. Attacking periods and parasitism percentages (PPs) of the identified parasitoid species were calculated. One solitary parasitoid species, Hyposoter ebeninus was found to attack P. rapae larvae in the field 110 days after transplantation. However, one hyperparasitoid species Baryscapus galactopus was recorded as an internal gregarious hyperparasitoid of H. ebeninus. The solitary larval parasitoid H. ebeninus strikes were recorded throughout the last five weeks of the season with a marked decline before harvesting. Although H. ebeninus revealed 42.00% abundance, it presented 21.69% PP on P. rapae larvae during the entire period of study. One solitary, Brachymeria femorata and two gregarious parasitoid species [Pteromalus puparum (L) and Tetrastichus sp. (Haliday) were recorded as P. rapae pupae parasitoids on October, 2 nd . Parasitism peak was recorded on October, 16 th with an average of 56.25%. The first appearance of the gregarious pupal parasitoid P. puparum was recorded on October, 9 th . Four weeks later, the second gregarious parasitoid (Tetrastichus sp.) was recorded on November, 6 th . Both pupal gregarious parasitoid species were found to be active until harvesting. The gregarious parasitoid P. puparum presented high PP (23.73%) as compared with Tetrastichus sp. which exhibited 6.96% PP during the entire period of study. In conclusion, two solitaries, one hyperparasitoid, and two gregarious parasitoid species were identified. Pupal gregarious parasitoid species together reduced P. rapae pupae populations by 30.69%. These parasitoids could be used in the IPM programs for this pest in the future. At the same time, the effect of hyperparsitoides must be taken into consideration.

Effect of Adult Nutrition at Different Concentrations on Reproduction and Longevity of <i>Bracon brevicornis</i>, Larval Parasitoid of Coconut Black-Headed Caterpillar

“…This is also supported by Tena et al, in which a two-fold increase of parasitized hosts by Aphytis melinus in a citrus agroecosystem, was evident on trees supplied with sugar [35]. Apart from that, other factors such as host instar stage [36] and progenies development strategy such as gregarious parasitoid [37] could also affect the parasitism rate.…”