Fall Armyworm in Africa:Which ‘Race’ is in the Race, and Why Does it Matter?

Srinivasan, R.; Malini, Periasamy; Othim, Stephen T O

doi:10.18520/cs/v114/i01/27-28

Cited by 10 publications

(9 citation statements)

References 15 publications

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“…frugiperda in Cameroon, we found 1.7% sequence divergence between the two S . frugiperda strains, which is greater than the 1% reported by [34], but it is still below the 2% usually recorded for confirmed congeneric species [51–53]. Intraspecific variation in the South African populations of S .…”

Section: Discussionmentioning

confidence: 59%

“…This provide evidence of the co-occurrence of both strains of S . frugiperda in Cameroon, in contrast to Nigeria, Sao-Tome and Tanzania where only one of the strain was recorded [19,34]. The two strains were recently shown to co-occur also in South Africa [35].…”

Section: Discussionmentioning

confidence: 99%

“…The DNA sequence dataset was completed with some S . frugiperda COI sequences from previous studies [19,34,35], retrieved from the NCBI GenBank database. Multiple sequence alignments for the sequence data were then generated in MAFFT [36].…”

Section: Methodsmentioning

confidence: 99%

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Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) in Cameroon: Case study on its distribution, damage, pesticide use, genetic differentiation and host plants

et al. 2019

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Maize farmers in sub-Saharan Africa recently experienced unusual damage in their farms, attributed to the fall armyworm (FAW) Spodoptera frugiperda (J. E. Smith). This pest was first recorded in Africa in 2016, but detailed information on its distribution and damage and farmer’s response in invaded areas are largely lacking. In this study, we determined FAW distribution, genetic diversity, host plants, crop damage, and farmers’ responses. S . frugiperda was recorded in the 10 regions of Cameroon. Average percentage of infested plants and damage severity (on a scale of 1 to 5) were lowest—20.7 ± 7.4% and 2.1 ± 0.1 respectively—in the Sahelian regions and greatest—69.0 ± 4.3% and 3.1 ± 0.1 respectively—in the Western Highlands. Altitude did not influence FAW incidence and severity and its larvae infrequently co-occurred with maize stemborers on the same plants, suggesting possible direct and/or indirect competition between the two groups of maize pests. In response to this new threat to maize production, farmers have opted for the application of synthetic pesticides. Although our experiments were not designed to determine pesticide efficacy, as parameters such as time since application were not considered, our observations suggest lack of a drastic effect on S . frugiperda infestations on maize. There were two haplotypes of FAW co-occurring in Cameroon corresponding to the rice and corn strains and separated by 1.7% sequence divergence, which does not support the existence of cryptic species. S . frugiperda larvae were also recorded on Sorghum bicolor (L.) Moench (10.6%), Solanum tuberosum L. (2.8%), Ipomoea batatas (L.) Lam. (1.9%), Saccharum officinarum L (0.8%), Phaseolus vulgaris L. (0.4%) and Gossypium hirsutum L. (1.9%). This study show that two strains are present in all agroecological zones in Cameroon, and probably in neighboring countries of central Africa sharing the same agroecologies. Management options should therefore consider the use of specific natural enemies and an informed decision of intervention based on strain capture and damage threshold, to avoid pesticide resistance that may arise from inadequate use of chemicals. Further studies should also be undertaken to assess the response of the two S . frugiperda strains to biopesticides and botanical insecticides.

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Section: Discussionmentioning

confidence: 59%

Section: Discussionmentioning

confidence: 99%

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Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) in Cameroon: Case study on its distribution, damage, pesticide use, genetic differentiation and host plants

et al. 2019

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“…In addition, as a pure leaf feeder, FAW larvae produced higher leaf damage and dispersal potential than stemborers. The devastating character in maize fields of FAW has been reported in several studies (Goergen et al, 2016; Srinivasan et al, 2018; Fotso Kuate et al, 2019).…”

Section: Discussionmentioning

confidence: 81%

Larval dispersal of the invasive fall armyworm, Spodoptera frugiperda, the exotic stemborer Chilo partellus, and indigenous maize stemborers in Africa

Sokame

Subramanian

Kilalo

et al. 2020

Entomologia Exp Applicata

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Larval dispersal either through ballooning or crawling results in a redistribution of the insect population and infestations within and between plants. In addition, invasive species, such as the fall armyworm (FAW), Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae), and the exotic stemborer Chilo partellus (Swinhoe) (Lepidoptera: Crambidae), may displace indigenous stemborers on maize in Africa. To test whether larval dispersal activity may play a role in the displacement of indigenous stemborers, larval dispersal was compared between FAW, C. partellus, and the indigenous species Busseola fusca (Fuller) and Sesamia calamistis (Hampson) (both Lepidoptera: Noctuidae). Twenty potted maize plants were infested with one batch of eggs either from stemborers (B. fusca, S. calamistis, or C. partellus) or from FAW and monitored in the greenhouse for ballooning activities. After egg hatching, both ballooning and non-ballooning larvae were identified according to species and counted. FAW neonate larvae had greater potential for ballooning off than stemborers, irrespective of species. For each species, more females dispersed than males, and their survival rate was higher than that of non-ballooning larvae. In addition, plant-to-plant larval movements were studied using 6.25-m 2 plots of caged maize in a completely randomized design with five replicates. FAW was found to have wider dispersal and plant damage potential than any of the stemborer species. In conclusion, in contrast to C. partellus, the invasive characteristic of FAW can be explained, in part, by its higher larval dispersal activity compared to stemborers. This difference in larval dispersal might also be considered in sampling plans for monitoring pest density in the field.

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“…Large infestations of fall armyworm in Africa were first reported in southwestern Nigeria in 2016 2 . Within the next two years infestations were observed in most sub-Saharan nations ranging from Kenya to the east and South Africa to the south [3][4][5][6][7] . In 2018 fall armyworm populations were found in multiple locations in India [8][9][10][11] , and now most recently in southeastern Asia [12][13][14] .…”

mentioning

confidence: 99%

Southeastern Asia fall armyworms are closely related to populations in Africa and India, consistent with common origin and recent migration

Nagoshi

Htain²,

Boughton

et al. 2020

Sci Rep

102

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The discovery of fall armyworm, a native of the Western Hemisphere, in western Africa in 2016 was rapidly followed by detections throughout sub-Saharan Africa, india, and most recently southeastern Asia. this moth pest has a broad host range that threatens such important crops as corn, rice, millet, and sorghum, creating concern for its potential impact on agriculture in the eastern Hemisphere. Although genetic data suggest populations sampled in Africa and india originate from a recent common source, it is not known whether this is the case for populations in southeastern Asia, nor whether the subgroup with a preference for rice and millet is present in the region. this study found through comparisons of genetic markers that the fall armyworm from Myanmar and southern china are closely related to those from Africa and india, suggesting a common origin for these geographically distant populations. the results are consistent with a single recent introduction into the eastern Hemisphere followed by rapid dispersion. the molecular similarities include discrepancies between the genetic markers that brings into question whether the subpopulation most likely to be a threat to rice and millet is present in significant numbers in Asia.

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Fall Armyworm in Africa:Which ‘Race’ is in the Race, and Why Does it Matter?

Cited by 10 publications

References 15 publications

Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) in Cameroon: Case study on its distribution, damage, pesticide use, genetic differentiation and host plants

Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) in Cameroon: Case study on its distribution, damage, pesticide use, genetic differentiation and host plants

Larval dispersal of the invasive fall armyworm, Spodoptera frugiperda, the exotic stemborer Chilo partellus, and indigenous maize stemborers in Africa

Southeastern Asia fall armyworms are closely related to populations in Africa and India, consistent with common origin and recent migration

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