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Ndjomatchoua FT, Guimapi RAY, Rossini L, Djouda BS, Pedro SA. A generalized risk assessment index for forecasting insect population under the effect of temperature. J Therm Biol 2024; 122:103886. [PMID: 38878392 DOI: 10.1016/j.jtherbio.2024.103886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 06/03/2024] [Accepted: 06/04/2024] [Indexed: 06/19/2024]
Abstract
Life history traits have been studied under various environmental factors, but the ability to combine them into a simple function to assess pest response to climate is still lacking complete understanding. This study proposed a risk index derived by combining development, mortality, and fertility rates from a stage-structured dynamic mathematical model. The first part presents the theoretical framework behind the risk index. The second part of the study is concerned with the application of the index in two case studies of major economic pest: the brown planthopper (Nilaparvata lugens) and the spotted wing drosophila (Drosophila suzukii), pests of rice crops and soft fruits, respectively. The mathematical calculations provided a single function composed of the main thermal biodemographic rates. This function has a threshold value that determines the possibility of population increase as a function of temperature. The tests carried out on the two pest species showed the capability of the index to describe the range of favourable conditions. With this approach, we were able to identify areas where pests are tolerant to climatic conditions and to project them on a geospatial risk map. The theoretical background developed here provided a tool for understanding the biogeography of Nilaparvata lugens and Drosophila suzukii. It is flexible enough to deal with mathematically simple (N. lugens) and complex (D. Suzukii) case studies of crop insect pests. It produces biologically sound indices that behave like thermal performance curves. These theoretical results also provide a reasonable basis for addressing the challenge of pest management in the context of seasonal weather variations and climate change. This may help to improve monitoring and design management strategies to limit the spread of pests in invaded areas, as some non-invaded areas may be suitable for the species to develop.
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Affiliation(s)
- Frank T Ndjomatchoua
- Department of Plant Sciences, School of the Biological Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom.
| | - Ritter A Y Guimapi
- Biotechnology and Plant Health Division, Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box 115, NO-1431 Ås, Norway.
| | - Luca Rossini
- Service d'Automatique et d'Analyse des Systèmes, Université Libre de Bruxelles (ULB), v. F.D. Roosvelt 50, CP 165/55, 1050, Brussels, Belgium.
| | - Byliole S Djouda
- Department of Physics, Faculty of Science, University of Yaoundé 1, P.O. Box 812, Ngoa Ekelle, Yaoundé, Cameroon
| | - Sansao A Pedro
- Departamento de Matemática e Informatica, Faculdade de Ciências, Universidade Eduardo Mondlane, 254, Maputo, Mozambique
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Kinyungu SW, Agbessenou A, Subramanian S, Khamis FM, Akutse KS. One stone for two birds: Endophytic fungi promote maize seedlings growth and negatively impact the life history parameters of the fall armyworm, Spodoptera frugiperda. Front Physiol 2023; 14:1253305. [PMID: 37900958 PMCID: PMC10600476 DOI: 10.3389/fphys.2023.1253305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 09/29/2023] [Indexed: 10/31/2023] Open
Abstract
The fall armyworm (FAW) Spodoptera frugiperda, is a voracious pest of cereals native to the Americas and which invaded Africa in 2016. Chemical control is the main management option, which however remains ineffective and unsustainable. Fungal endophytes are increasingly used as alternative for the management of insect pests of economic importance. This study assessed the potential of eight endophytic fungal isolates to colonize maize plant and their ability to promote seedlings growth through seed and foliar inoculations, as well as their suppressive effects on FAW. Fungal colonization rates of different plant parts by the endophytes varied as per the inoculation methods. Beauveria bassiana ICIPE 279 colonized more than 60% of all the seedling parts while B. bassiana G1LU3 only colonized stem (25%) and leaf (5%) tissues through foliar inoculation. Trichoderma atroviride F2S21, T. asperellum M2RT4, T. harzianum F2R41, Trichoderma sp. F2L41, Hypocrea lixii F3ST1 and Fusarium proliferatum F2S51 successfully colonized all the plant parts and therefore were selected and further evaluated through seed inoculation for their endophytic persistence, effect on plant growth, and pathogenicity to Spodoptera frugiperda immature and adult stages. Weekly assessment showed varied effect of the endophytes on maize plant growth parameters compared to the control. During the first week, percentage colonization of the plant parts ranges between 90%-100%, 65%-100%, and 60%-100%, in the roots, stems, and leaves, respectively for all the five tested isolates. However, the colonization pattern/rates significantly decreased over time for H. lixii F3ST1 in the stems and leaves, and for T. harzianum F2R41 in the leaves and for T. asperellum M2RT4 in the roots. In addition, T. harzianum F2R41 outperformed all the other isolates in boosting the plant height, whereas H. lixii F3ST1 and T. asperellum M2RT4 outperformed all the other isolates in increasing the wet and dry shoots weight. Furthermore, the number of egg masses laid on endophytically-colonized maize plants varied among the treatments. Trichoderma asperellum M2RT4 and H. lixii F3ST1 endophytically-colonized maize plants significantly reduced the number of egg masses and the defoliation/feeding rates of the pest compared to the control. Additionally, T. harzianum F2R41 had the highest negative impact on the pupation and adult emergence of S. frugiperda with a female-biased sex ratio. Our findings indicate that T. asperellum M2RT4, T. harzianum F2R41, and H. lixii F3ST1 hold a potential to be developed as endophytic-fungal-based biopesticides for sustainable management of S. frugiperda and as plant growth promoters.
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Affiliation(s)
- Sharon W. Kinyungu
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Ayaovi Agbessenou
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Julius Kühn Institute (JKI) - Federal Research Centre for Cultivated Plants, Institute for Biological Control, Dossenheim, Germany
- Center for Development Research (ZEF), Department of Ecology and Natural Resources Management, University of Bonn, Bonn, Germany
| | - Sevgan Subramanian
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Fathiya M. Khamis
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Komivi S. Akutse
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Unit of Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
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Mediouni Ben Jemâa J, Soltani A, Djebbi T, Mejri I, Kanyesigye D, Otim MH. The Maize Caterpillar Mythimna (= Leucania) loreyi (Duponchel, 1827) (Lepidoptera: Noctuidae): Identification, Distribution, Population Density and Damage in Tunisia. INSECTS 2023; 14:786. [PMID: 37887798 PMCID: PMC10607259 DOI: 10.3390/insects14100786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/24/2023] [Accepted: 07/26/2023] [Indexed: 10/28/2023]
Abstract
Surveys were conducted during 2020 and 2021 to study the emerging lepidopteran pests inflicting cereals in Tunisia, with specific emphasis on maize and sorghum crops. A species was collected from traps placed in the Jendouba, Bizerte, Nabeul and Gabes regions. Thus, this study carried out first report on its identification, distribution, population density and damage. Results showed that M. loreyi was abundant in all prospected areas, with total adult captures reaching 4779 and 9499 moths on sorghum and maize, respectively, during 2020. Moreover, the mean infestation percentage reached its maximum during August at 31.05% and 20.69% for the Jendouba and Bizerte regions, respectively, while the highest infestations were observed in the Gabes and Nabeul regions during July, with respective mean values of 13.54% and 21.35%. In addition, results revealed that the highest pest incidence occurred in the Gabes region, with values of 11.1 ± 0.47 and 5.7 ± 0.48 during 2020 and 2021, respectively. Additionally, results pointed out that M. loreyi achieved two summer generations in the different localities of Tunisia. Overall, this study provides basic insights into the ecology and population biology of M. loreyi, which are required to establish an effective pest control program.
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Affiliation(s)
- Jouda Mediouni Ben Jemâa
- Laboratory of Biotechnology Applied to Agriculture LR11INRAT06, National Agricultural Research Institute of Tunisia (INRAT), University of Carthage, Tunis 1004, Tunisia; (A.S.); (T.D.); (I.M.)
| | - Abir Soltani
- Laboratory of Biotechnology Applied to Agriculture LR11INRAT06, National Agricultural Research Institute of Tunisia (INRAT), University of Carthage, Tunis 1004, Tunisia; (A.S.); (T.D.); (I.M.)
| | - Tasnim Djebbi
- Laboratory of Biotechnology Applied to Agriculture LR11INRAT06, National Agricultural Research Institute of Tunisia (INRAT), University of Carthage, Tunis 1004, Tunisia; (A.S.); (T.D.); (I.M.)
| | - Ines Mejri
- Laboratory of Biotechnology Applied to Agriculture LR11INRAT06, National Agricultural Research Institute of Tunisia (INRAT), University of Carthage, Tunis 1004, Tunisia; (A.S.); (T.D.); (I.M.)
| | - Dalton Kanyesigye
- National Crops Resources Research Institute (NaCRRI), Kampala P.O. Box 7084, Uganda; (D.K.); (M.H.O.)
| | - Michael Hilary Otim
- National Crops Resources Research Institute (NaCRRI), Kampala P.O. Box 7084, Uganda; (D.K.); (M.H.O.)
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Abdel-Rahman EM, Kimathi E, Mudereri BT, Tonnang HE, Mongare R, Niassy S, Subramanian S. Computational biogeographic distribution of the fall armyworm ( Spodoptera frugiperda J.E. Smith) moth in eastern Africa. Heliyon 2023; 9:e16144. [PMID: 37265631 PMCID: PMC10230198 DOI: 10.1016/j.heliyon.2023.e16144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 04/14/2023] [Accepted: 05/06/2023] [Indexed: 06/03/2023] Open
Abstract
The fall armyworm (FAW), Spodoptera frugiperda J.E. Smith, has caused massive maize losses since its attack on the African continent in 2016, particularly in east Africa. In this study, we predicted the spatial distribution (established habitat) of FAW in five east African countries viz., Kenya, Tanzania, Rwanda, Uganda, and Ethiopia. We used FAW occurrence observations for three years i.e., 2018, 2019, and 2020, the maximum entropy (MaxEnt) model, and bioclimatic, land surface temperature (LST), solar radiation, wind speed, elevation, and landscape structure data (i.e., land use and land cover and maize harvested area) as explanatory variables. The explanatory variables were used as inputs into a variable selection experiment to select the least correlated ones that were then used to predict FAW establishment, i.e., suitability areas (very low suitability - very high suitability). The shared socio-economic pathways, SSP2-4.5 and SSP5-8.5 for the years 2030 and 2050 were used to predict the effect of future climate scenarios on FAW establishment. The results demonstrated that FAW establishment areas in eastern Africa were based on the model strength and true performance (area under the curve: AUC = 0.87), but not randomly. Moreover, ∼27% of eastern Africa is currently at risk of FAW establishment. Predicted FAW risk areas are expected to increase to ∼29% (using each of the SSP2-4.5 and SSP5-8.5 scenarios) in the year 2030, and to ∼38% (using SSP2-4.5) and ∼35% (using SSP5-8.5) in the year 2050 climate scenarios. The LULC, particularly croplands and maize harvested area, together with temperature and precipitation bioclimatic variables provided the highest permutation importance in determining the occurrence and establishment of the pest in eastern Africa. Specifically, the study revealed that FAW was sensitive to isothermality (Bio3) rather than being sensitive to a single temperature value in the year. FAW preference ranges of temperature, precipitation, elevation, and maize harvested area were observed, implying the establishment of a once exotic pest in critical maize production regions in eastern Africa. It is recommended that future studies should thus embed the present study's modeling results into a dynamic platform that provides near-real-time predictions of FAW spatial occurrence and risk at the farm scale.
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Sekabira H, Tepa-Yotto GT, Ahouandjinou ARM, Thunes KH, Pittendrigh B, Kaweesa Y, Tamò M. Are digital services the right solution for empowering smallholder farmers? A perspective enlightened by COVID-19 experiences to inform smart IPM. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2023. [DOI: 10.3389/fsufs.2023.983063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The COVID-19 pandemic, surprised many through its impact on the food systems, resulting in collapses in the food production value chains and in the integrated pest disease management sector with fatal outcomes in many places. However, the impact of COVID-19 and the digital experience perspective on Integrating Pest Management (IPM) is still yet to be understood. In Africa, the impact was devastating, mostly for the vulnerable smallholder farm households, who were rendered unable to access markets to purchase inputs and sell their produce during the lockdown period. By using a holistic approach the paper reviews different Information and Communications Technologies (ICTs), digitalization, and how this enhanced the capacity of smallholder farmers resilient, and inform their smart-IPM practices in order to improve food systems' amidst climate change during and in the post-COVID-19 period. Different digital modalities were adopted to ensure continuous food production, access to inputs and finances, and selling surplus production among others. This was largely possible by using ICTs to deliver these needed services digitally. The study shares contributions and capacity perspectives of ICTs for empowering smallholder farmers to boost the resilience of their food systems based on COVID-19 successful experiences. Thus digital solutions must be embraced in the delivery of extension service on pest management and good agronomic practices, money transfers for purchasing inputs, receiving payment for sold farm produce, and markets information exchange. These are key avenues through which digital solutions strategically supported smallholder-based food systems through the pandemic.
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Kasoma C, Shimelis H, Laing MD, Mekonnen B. Fall Armyworm Infestation and Development: Screening Tropical Maize Genotypes for Resistance in Zambia. INSECTS 2022; 13:1020. [PMID: 36354844 PMCID: PMC9694902 DOI: 10.3390/insects13111020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 10/19/2022] [Accepted: 11/01/2022] [Indexed: 06/16/2023]
Abstract
Knowledge of fall armyworm (FAW) (Spodoptera frugiperda J.E. Smith) rearing, infestation and development and precision screening protocols are preconditions for the successful introgression of resistance genes into farmer-preferred varieties. We aimed to determine FAW developmental stages, screen tropical maize and select resistant lines under controlled conditions in Zambia. Field-collected FAW samples constituting 30 egg masses and 60 larvae were reared using maize leaf- and stalk-based and soy- and wheat flour-based diets at 27 ± 1 °C, 60 ± 5% relative humidity and 12 h day length. The resulting neonates were separated into sets A and B. The life cycles of set A and field-collected larvae were monitored to document the FAW developmental features. Set B neonates were used to infest the seedlings of 63 diverse tropical maize genotypes. Egg, larva, pupa and adult stages had mean durations of 2, 24, 20 and 12 days, respectively. Test maize genotypes revealed significant differences (p < 0.05) based on FAW reaction types, with lines TL13159, TL02562, TL142151, VL050120 and CML548-B exhibiting resistance reactions, while CML545-B, CZL1310c, CZL16095, EBL169550, ZM4236 and Pool 16 displayed moderate resistance. These genotypes are candidate sources of FAW resistance for further breeding. This study will facilitate controlled FAW rearing for host screening in the integration of FAW resistance into market-preferred maize lines.
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Affiliation(s)
- Chapwa Kasoma
- African Centre for Crop Improvement, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
- Centre for Agriculture and Bioscience International (CAB International) Southern Africa Centre, 5834 Mwange Close, Kalundu, Lusaka P.O. Box 37589, Zambia
| | - Hussein Shimelis
- African Centre for Crop Improvement, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
| | - Mark D. Laing
- African Centre for Crop Improvement, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
| | - Bethelihem Mekonnen
- Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa
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