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

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.

A Fuzzy-Based Model to Predict the Spatio-Temporal Performance of the Dolichogenidea gelechiidivoris Natural Enemy against Tuta absoluta under Climate Change

“…Various ecological and phenological models have recently been used to predict the establishment of different parasitoid species under current and/or future scenarios in Africa [ 8 ]. Using Insect Life Cycle Modelling (ILCYM) software, the thermal thresholds and demographics parameters of D. gelechidivoris have been investigated based on the thermal response curves [ 38 ].…”

“…Significant crop loss caused by T. absoluta can be attributed to several factors that include the pest’s high dispersal capacity [ 7 ], wide thermal tolerance [ 8 ], high reproduction rate [ 8 ], lack of efficient co-evolved natural enemy to suppress its exploding population [ 9 ], and ability to adapt to the new ecosystems [ 10 , 11 ]. Due to enormous yield losses attributable to T .…”

“…Using temperature and other climatic variables, several models have been proposed to project the habitat suitability for the establishment of natural enemies in Africa [ 8 ]. Indeed, these models have generated an important body of knowledge with regard to the potential parasitoid establishment.…”

Identification, Microhabitat, and Ecological Niche Prediction of Two Promising Native Parasitoids of Tuta absoluta in Kenya

“…The tomato production system was also recorded as either an open field or greenhouse/screen house production. Additionally, an average number of N. tenuis per kilogram of tomato leaves were estimated and four classes were obtained for this variable 0 = absence of N. tenuis , [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ] = low-level presence of N. tenuis , [ 50 ,…”

“…The assemblage of native parasitoids in various tomato-producing areas needs to be documented if they are to be incorporated into augmentative and conservative biological control approaches for the management of T. absoluta. Furthermore, habitat and climate are significant factors limiting the distribution and abundance of insect pests, as well as their physiology and reproduction [ 37 , 38 , 39 , 40 , 41 , 42 ]. Parasitoids and predator distribution on a local scale, are also affected by agronomic practices such as pesticide application [ 43 , 44 ].…”