Insecticide use, farmers’ self-reported health status, and genetically modified cowpea in Nigeria: Findings from a clustered randomized controlled trial with causal

Excessive insecticide use in smallholder agriculture can threaten human health and the environment. We evaluate the effects of receiving a genetically modified cowpea variety that confers resistance to the legume pod borer (Maruca vitrata) using a clustered randomized controlled trial with an encour...

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Autores principales: Amare, Mulubrhan, Andam, Kwaw S., Spielman, David J., Bamiwuye, Temilolu, Nwagboso, Chibuzo, Zambrano, Patricia, Chambers, Judith A.
Formato: Artículo preliminar
Lenguaje:Inglés
Publicado: International Food Policy Research Institute 2025
Materias:
Acceso en línea:https://hdl.handle.net/10568/179030
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author Amare, Mulubrhan
Andam, Kwaw S.
Spielman, David J.
Bamiwuye, Temilolu
Nwagboso, Chibuzo
Zambrano, Patricia
Chambers, Judith A.
author_browse Amare, Mulubrhan
Andam, Kwaw S.
Bamiwuye, Temilolu
Chambers, Judith A.
Nwagboso, Chibuzo
Spielman, David J.
Zambrano, Patricia
author_facet Amare, Mulubrhan
Andam, Kwaw S.
Spielman, David J.
Bamiwuye, Temilolu
Nwagboso, Chibuzo
Zambrano, Patricia
Chambers, Judith A.
author_sort Amare, Mulubrhan
collection Repository of Agricultural Research Outputs (CGSpace)
description Excessive insecticide use in smallholder agriculture can threaten human health and the environment. We evaluate the effects of receiving a genetically modified cowpea variety that confers resistance to the legume pod borer (Maruca vitrata) using a clustered randomized controlled trial with an encouragement design in Nigeria. We find that farmers who received the pod borer-resistant (PBR) cowpea with complementary inputs significantly reduce insecticide volumes and report fewer days of insecticide-related illness compared to farmers who only received a conventional cowpea variety. Farmers receiving PBR cowpea alone experience smaller, mostly insignificant reductions. To explore heterogeneous responses, we combine ANCOVA (analysis of covariance) interactions with machine learning-based Causal Forest estimates of Conditional Average Treatment Effects (CATEs). Results reveal that smaller, less wealthy, and labor-constrained households experience the largest reductions in insecticide use and health improvements, whereas wealthier farmers or those with higher baseline spraying practices experience lower reductions. Women-managed plots exhibit modestly higher responsiveness. Our findings highlight the importance of moving beyond average effects and seed distribution toward targeted, context-specific interventions that account for behavioral and resource constraints in smallholder farming systems.
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spelling CGSpace1790302025-12-19T15:53:45Z Insecticide use, farmers’ self-reported health status, and genetically modified cowpea in Nigeria: Findings from a clustered randomized controlled trial with causal Amare, Mulubrhan Andam, Kwaw S. Spielman, David J. Bamiwuye, Temilolu Nwagboso, Chibuzo Zambrano, Patricia Chambers, Judith A. insecticides farmers health genetically modified foods cowpeas randomized controlled trials machine learning Excessive insecticide use in smallholder agriculture can threaten human health and the environment. We evaluate the effects of receiving a genetically modified cowpea variety that confers resistance to the legume pod borer (Maruca vitrata) using a clustered randomized controlled trial with an encouragement design in Nigeria. We find that farmers who received the pod borer-resistant (PBR) cowpea with complementary inputs significantly reduce insecticide volumes and report fewer days of insecticide-related illness compared to farmers who only received a conventional cowpea variety. Farmers receiving PBR cowpea alone experience smaller, mostly insignificant reductions. To explore heterogeneous responses, we combine ANCOVA (analysis of covariance) interactions with machine learning-based Causal Forest estimates of Conditional Average Treatment Effects (CATEs). Results reveal that smaller, less wealthy, and labor-constrained households experience the largest reductions in insecticide use and health improvements, whereas wealthier farmers or those with higher baseline spraying practices experience lower reductions. Women-managed plots exhibit modestly higher responsiveness. Our findings highlight the importance of moving beyond average effects and seed distribution toward targeted, context-specific interventions that account for behavioral and resource constraints in smallholder farming systems. 2025-12-18 2025-12-18T22:05:37Z 2025-12-18T22:05:37Z Working Paper https://hdl.handle.net/10568/179030 en https://hdl.handle.net/10568/145073 https://hdl.handle.net/10568/145074 https://hdl.handle.net/10568/178553 Open Access application/pdf International Food Policy Research Institute Amare, Mulubrhan; Andam, Kwaw S.; Spielman, David J.; Bamiwuye, Temilolu; Nwagboso, Chibuzo; et al. 2025. Insecticide use, farmers’ self-reported health status, and genetically modified cowpea in Nigeria: Findings from a clustered randomized controlled trial with causal. IFPRI Discussion Paper 2388. Washington, DC: International Food Policy Research Institute. https://hdl.handle.net/10568/179030
spellingShingle insecticides
farmers
health
genetically modified foods
cowpeas
randomized controlled trials
machine learning
Amare, Mulubrhan
Andam, Kwaw S.
Spielman, David J.
Bamiwuye, Temilolu
Nwagboso, Chibuzo
Zambrano, Patricia
Chambers, Judith A.
Insecticide use, farmers’ self-reported health status, and genetically modified cowpea in Nigeria: Findings from a clustered randomized controlled trial with causal
title Insecticide use, farmers’ self-reported health status, and genetically modified cowpea in Nigeria: Findings from a clustered randomized controlled trial with causal
title_full Insecticide use, farmers’ self-reported health status, and genetically modified cowpea in Nigeria: Findings from a clustered randomized controlled trial with causal
title_fullStr Insecticide use, farmers’ self-reported health status, and genetically modified cowpea in Nigeria: Findings from a clustered randomized controlled trial with causal
title_full_unstemmed Insecticide use, farmers’ self-reported health status, and genetically modified cowpea in Nigeria: Findings from a clustered randomized controlled trial with causal
title_short Insecticide use, farmers’ self-reported health status, and genetically modified cowpea in Nigeria: Findings from a clustered randomized controlled trial with causal
title_sort insecticide use farmers self reported health status and genetically modified cowpea in nigeria findings from a clustered randomized controlled trial with causal
topic insecticides
farmers
health
genetically modified foods
cowpeas
randomized controlled trials
machine learning
url https://hdl.handle.net/10568/179030
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