SHORT COMMUNICATION First record of the impact of the parasitism of Cecidochares connexa (Diptera: Tephritidae) by a solitary larval ectoparasitoid in West Africa: Cause for concern? Pascal Osa Aigbedion-Atalor 1,5 • Itohan Idemudia 2 • Arne B. R. Witt 3 • Michael D. Day 4 Received: 18 August 2018 / Accepted: 18 September 2018 Ó Deutsche Phytomedizinische Gesellschaft 2018 Abstract Cecidochares connexa is currently the only effective biological control agent of Chromolaena odorata an invasive weed in West Africa. Recently, an ectoparasitoid species belonging to the Ormyrus genus was found parasitizing C. connexa in three regions of Ghana. Adult parasitoid emergence percentages varied between 16 and 21%. This raises concerns about its impact on C. connexa populations and the overall biocontrol of C. odorata. New field surveys to determine the distribution range of Ormyrus sp. and its impact on C. connexa should be quickly addressed in West Africa. Keywords Post-release evaluation Á Ormyrus sp. Á Stem-galling fly Á Chromolaena odorata Á West Africa Cecidochares connexa (Macquart) (Diptera: Tephritidae), a specialist biological control agent of the neotropical shrub Chromolaena odorata King and Robinson (Asteraceae) induces galls on the terminal and axillary buds of the plant (McFadyen et al. 2003; Day et al. 2016). The gall fly was introduced into Cote d’Ivoire in 2003 and first detected in Ghana in 2014 (Paterson and Akpabey 2014). Prior to C. connexa, the introduction and establishment of the spe- cialist folivore, Pareuchaetes pseudoinsulata Rego Baros (Lepidoptera: Erebidae), had a significant impact on the weed in the 1990s and is currently widely distributed across West Africa (Aigbedion-Atalor et al. 2018a). However, its density crashed within a decade of its estab- lishment and has since been less effective in managing the impact of the weed on extant vegetation and biosecurity in West Africa (Uyi and Igbinosa 2013). Post-release evaluation studies conducted in 2015 showed that C. connexa is distributed in high densities in southern Ghana (Aigbedion-Atalor et al. 2018b, in press), which is crucial for its long-term management of C. odorata (e.g., Day et al. 2013; Reddy et al. 2013). A recent study showed a significant reduction in the density of C. odorata in Ghana due to high densities of C. connexa (Aigbedion-Atalor et al. ‘‘2018c submitted’’). In 2016, we collected C. connexa galls in the Greater Accra region of Ghana and inadvertently found the larvae of some had been parasitized by an un-identified larval ectoparasitoid. This finding precipitated the collection of galls from four (Ashanti, Greater Accra, Central, and Eastern) regions in the country, with the intention of assessing the distribution and impact of the parasitoid on C. connexa in Ghana. To do this, at each of the four selected regions, 15 C. connexa galls, with 12 replicates each, were collected by cutting off galls on C. odorata stems with a pair of secateurs. Galls were then transported in Plexiglas cages (20 cm 9 20 cm 9 20 cm) to the African Regional Postgraduate Pro- gramme In Insect Science (ARPPIS) laboratory, at the University of Ghana, Legon. In the laboratory, galls were transferred from the initial transport cages into new insect- rearing cages (10 cm 9 10 cm 9 10 cm) which were previously washed and cleaned with distilled water. Location and regional names were affixed to the sides of & Pascal Osa Aigbedion-Atalor patalor@icipe.org 1 International Center of Insect Physiology and Ecology, Nairobi, Kenya 2 Department of Animal and Environmental Biology, University of Benin, Benin City, Edo State, Nigeria 3 CABI, Canary Bird 673, Limuru Road, Muthaiga, Nairobi, Kenya 4 Biosecurity Queensland, Department of Agriculture and Fisheries, Ecosciences Precinct, Brisbane, Australia 5 Centre for Biological Control, Department of Zoology and Entomology, Rhodes University, Grahamstown, South Africa 123 Journal of Plant Diseases and Protection https://doi.org/10.1007/s41348-018-0189-x