A deadly encounter: Alien invasive Spodoptera frugiperda in Africa and indigenous natural enemy, Cotesia icipe (Hymenoptera, Braconidae)

Samira Abuelgasim Mohamed; Mark Wamalwa; Francis Obala; Henri E Z Tonnang; Tadele Tefera; Paul-Andre Calatayud; Sevgan Subramanian; Sunday Ekesi

doi:10.1371/journal.pone.0253122

A deadly encounter: Alien invasive Spodoptera frugiperda in Africa and indigenous natural enemy, Cotesia icipe (Hymenoptera, Braconidae)

PLoS One. 2021 Jul 16;16(7):e0253122. doi: 10.1371/journal.pone.0253122. eCollection 2021.

Authors

Samira Abuelgasim Mohamed¹, Mark Wamalwa¹, Francis Obala¹, Henri E Z Tonnang¹, Tadele Tefera², Paul-Andre Calatayud¹, Sevgan Subramanian¹, Sunday Ekesi¹

Affiliations

¹ International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya.
² International Centre of Insect Physiology and Ecology (icipe), Addis Ababa, Ethiopia.

Abstract

The invasion and wide spread of Spodoptera frugiperda represent real impediments to food security and the livelihood of the millions of maize and sorghum farming communities in the sub-Saharan and Sahel regions of Africa. Current management efforts for the pest are focused on the use of synthetic pesticides, which are often economically unviable and are extremely hazardous to the environment. The use of biological control offers a more economically and environmentally safer alternative. In this study, the performance of the recently described parasitoid, Cotesia icipe, against the pest was elucidated. We assessed the host stage acceptability by and suitability for C. icipe, as well as its ovigenic status. Furthermore, the habitat suitability for the parasitoid in the present and future climatic conditions was established using Maximum Entropy (MaxEnt) algorithm and the Genetic Algorithm for Rule-set Prediction (GARP). Cotesia icipe differentially accepted the immature stages of the pest. The female acceptance of 1st and 2nd instar larvae for oviposition was significantly higher with more than 60% parasitism. No oviposition on the egg, 5th and 6th larval instars, and pupal stages was observed. Percentage of cocoons formed, and the number of emerged wasps also varied among the larval stages. At initial parasitism, parasitoid progenies, time to cocoon formation and overall developmental time were significantly affected by the larval stage. Egg-load varied significantly with wasp age, with six-day-old wasps having the highest number of mature eggs. Ovigeny index of C. icipe was 0.53. Based on the models, there is collinearity in the ecological niche of the parasitoid and the pest under current and future climate scenarios. Eastern, Central and parts of coastal areas of western Africa are highly suitable for the establishment of the parasitoid. The geographic distribution of the parasitoid would remain similar under future climatic conditions. In light of the findings of this study, we discuss the prospects for augmentative and classical biological control of S. frugiperda with C. icipe in Africa.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Ecosystem
Ethiopia
Female
Host-Parasite Interactions
Introduced Species
Kenya
Larva / parasitology
Male
Oviposition
Pest Control, Biological / methods
Spodoptera / growth & development
Spodoptera / parasitology*
Wasps*

Grants and funding

The authors gratefully acknowledge the financial support for this research by the following organizations and agencies: The European Union (through fund for the project “Integrated pest management strategy to counter the threat of invasive fall armyworm to food security and Eastern Africa (FAW-IPM)”), FOOD/2018402-634; UK’s Foreign, Commonwealth & Development Office (FCDO); the Swedish International Development Cooperation Agency (Sida); the Swiss Agency for Development and Cooperation (SDC); the Federal Democratic Republic of Ethiopia; and the Government of the Republic of Kenya. The views expressed herein do not necessarily reflect the official opinion of the donors.