First record of parasitoids Megastigmus sp. and Quadrastichus mendeli as potential biological control agents of eucalyptus gall inducers in Tanzania

Abstract

Leptocybe invasa and Ophelimus maskelli (Hymenoptera: Eulophidae) are serious pests causing damage to eucalypt plantations in Tanzania. Biological control is considered the best alternative to other control methods, both ecologically and economically. Thus far, no parasitoid of the eucalyptus gall wasps documented or reported. Likewise, the number of parasitoid species and their parasitic capacities are unknown. Therefore, the study investigated the parasitoids of the eucalypt gall inducer from October 2021 to April 2022. Galls were collected from E. tereticornis and E. grandis x E. camaldulensis clones and reared until wasps emerged. The emerged wasps were sorted and identified at the Sokoine University of Agriculture, Tanzania, and the Insect Biosystematics Laboratory at IPB University, Indonesia. Two species of parasitoids of eucalyptus gall-inducers in Tanzania were first collected and identified as Megastigmus sp. (Torymidae) and Quadrastichus mendeli (Eulophidae). In Korogwe, North Ruvu, and Morogoro plantation areas, the percentages of parasitization for the two parasitoids combined were 29.7%, 64%, and 33.3%, respectively. A higher parasitization rate was observed from L. invasa galls in the E. grandis x E. camaldulensis clones. These parasitoids can be potential biological control agent candidates to control the pest. However, future monitoring is needed to determine their distribution, host specificity, interactions, and efficacy.