| Literature DB >> 34735485 |
Zewdu Abro1, Emily Kimathi2, Hugo De Groote3, Tadele Tefera1, Subramanian Sevgan2, Saliou Niassy2, Menale Kassie2.
Abstract
Since 2016, fall armyworm (FAW) has threatened sub-Saharan 'Africa's fragile food systems and economic performance. Yet, there is limited evidence on this transboundary pest's economic and food security impacts in the region. Additionally, the health and environmental consequences of the insecticides being used to control FAW have not been studied. This paper presents evidence on the impacts of FAW on maize production, food security, and human and environmental health. We use a combination of an agroecology-based community survey and nationally representative data from an agricultural household survey to achieve our objectives. The results indicate that the pest causes an average annual loss of 36% in maize production, reducing 0.67 million tonnes of maize (0.225 million tonnes per year) between 2017 and 2019. The total economic loss is US$ 200 million, or 0.08% of the gross domestic product. The lost production could have met the per capita maize consumption of 4 million people. We also find that insecticides to control FAW have more significant toxic effects on the environment than on humans. This paper highlights governments and development partners need to invest in sustainable FAW control strategies to reduce maize production loss, improve food security, and protect human and environmental health.Entities:
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Year: 2021 PMID: 34735485 PMCID: PMC8568106 DOI: 10.1371/journal.pone.0257736
Source DB: PubMed Journal: PLoS One ISSN: 1932-6203 Impact factor: 3.240
Area under maize cultivation and production by agro-ecological zones in Ethiopia.
| Agro-ecological zones | Cultivated land (millions of ha) | Production (millions of tonnes) | ||||
|---|---|---|---|---|---|---|
| 2017 | 2018 | 2019 | 2017 | 2018 | 2019 | |
| Wet upper mid-altitudes | 0.85 | 0.97 | 0.85 | 3.74 | 4.27 | 3.78 |
| Wet lower mid-altitudes | 0.05 | 0.03 | 0.03 | 0.14 | 0.09 | 0.09 |
| Dry mid-altitudes | 0.34 | 0.29 | 0.34 | 1.00 | 0.88 | 1.37 |
| Wet lowlands | 0.01 | 0.03 | 0.03 | 0.04 | 0.11 | 0.13 |
| Dry lowlands | 0.04 | 0.04 | 0.02 | 0.08 | 0.05 | 0.07 |
| Highlands | 0.69 | 0.85 | 0.82 | 2.95 | 3.59 | 3.59 |
| Total | 1.98 | 2.20 | 2.08 | 7.95 | 8.98 | 9.03 |
Source: CSA’s agricultural sample survey (2017–2019).
Fig 1The study areas and the location of sample communities within maize mega-environments.
Fig 2Pictures of lepidopterous insect pests shown to farmers.
A) stemborers (either Chilo partellus (A1), or Busseola Fusca (A2); B) Spodoptera exempta; and C) Spodoptera frugiperda, obtained from [6] with permission.
Attainable yield, actual yield, and average land size in Ethiopia (2017–2019).
| Agro-ecological zones | Attainable yield (tonnes/ha)-( | Actual yield (tonnes/ha)-( | Yield losses due to FAW and other stresses (tonnes/ha)-( | Average land size (ha)-( | Number of farmers (millions) ( |
|---|---|---|---|---|---|
| A | B | C = A-B | D | E | |
| Wet upper mid-altitudes | 4.02 | 2.76 | 1.26 | 0.12 | 3.41 |
| (0.10) | (0.08) | (0.05) | (0.08) | (0.02) | |
| Wet lower mid-altitudes | 5.08 | 3.73 | 1.35 | 0.08 | 0.32 |
| (0.90) | (0.82) | (0.15) | (0.01) | (0.01) | |
| Dry mid-altitudes | 4.40 | 2.86 | 1.54 | 0.14 | 1.29 |
| (0.13) | (0.13) | (0.07) | (0.01) | (0.01) | |
| Dry lowlands | 3.10 | 2.47 | 0.63 | 0.10 | 0.33 |
| (0.12) | (0.16) | (0.11) | (0.02) | (0.01) | |
| Highlands | 4.13 | 2.88 | 1.25 | 0.11 | 3.80 |
| (0.14) | (0.11) | (0.06) | (0.06) | (0.01) | |
| Average | 4.11 | 2.82 | 1.29 | 0.12 | 9.28 |
| (0.07) | (0.06) | (0.03) | (0.04) | (0.01) |
Note: Standard errors in parenthesis.
Sources: Columns A and B are from the community survey data; columns D and E are from the CSA’s agricultural sample survey.
Farmers’ awareness and knowledge of FAW in the study areas (%).
| Agro-ecological zones | Awareness of FAW (%) | Correctly identified FAW (%) |
|---|---|---|
| Wet upper mid-altitudes | 92.00 | 70.00 |
| Wet lower mid-altitudes | 100.00 | 100.00 |
| Dry mid-altitudes | 99.00 | 88.00 |
| Dry lowlands | 100.00 | 100.00 |
| Highlands | 92.00 | 80.00 |
| Average | 97.00 | 88.00 |
Source: Community survey.
Fig 3Farmers’ FAW control strategies by agro-ecological zones.
FAW control support to the study communities.
| External support: | Wet Upper Mid-altitudes | Wet Lower Mid-altitudes | Dry Mid-altitudes | Dry Lowlands | Highlands | Average |
|---|---|---|---|---|---|---|
| Not at all | 61.00 | 100.00 | 63.00 | 0.00 | 61.00 | 61.00 |
| Increased | 21.00 | 0.00 | 30.00 | 0.00 | 18.00 | 21.00 |
| Same | 7.00 | 0.00 | 0.00 | 100.00 | 5.00 | 6.00 |
| Decreased | 10.00 | 0.00 | 5.00 | 0.00 | 15.00 | 11.00 |
| Do not know | 2.00 | 0.00 | 1.00 | 0.00 | 0.00 | 1.00 |
| Total | 100.00 | 100 | 100.00 | 100.00 | 100.00 | 100.00 |
Source: Community survey.
Fig 4Geographic distribution of average farmers affected (%) by FAW (2017–2019).
Proportion of farmers affected by FAW (%).
| Agro-ecological zones | 2017 | 2018 | 2019 | Average |
|---|---|---|---|---|
| Wet upper mid-altitudes | 36.40 | 39.64 | 39.71 | 38.60 |
| (2.51) | (2.49) | (2.28) | (1.40) | |
| Wet lower mid-altitudes | 55.00 | 55.00 | 67.50 | 59.17 |
| (20.00) | (25.00) | (27.50) | (11.21) | |
| Dry mid-altitudes | 44.02 | 41.71 | 45.27 | 43.68 |
| (4.73) | (5.07) | (4.96) | (2.82) | |
| Dry lowlands | 20.00 | 12.50 | 17.50 | 16.67 |
| (0.00) | (2.50) | (2.50) | (1.67) | |
| Highlands | 37.95 | 42.39 | 44.75 | 41.67 |
| (3.58) | (4.06) | (4.07) | (2.25) | |
| Average | 38.07 | 40.68 | 42.13 | 40.30 |
| (1.86) | (1.97) | (1.89) | (1.10) |
Note: Standard errors of the mean are reported in parenthesis;
the standard errors are zero because FGD participants provided 20% loss for all data points.
Source: Community survey.
Yield losses due to FAW (%).
| Agro-ecological zones | 2017 | 2018 | 2019 | Average |
|---|---|---|---|---|
| Wet upper mid-altitudes | 34.37 | 34.71 | 35.82 | 34.97 |
| (2.14) | (1.96) | (2.05) | (1.18) | |
| Wet lower mid-altitudes | 35.00 | 32.50 | 35.00 | 34.17 |
| (5.00) | (2.50) | (5.00) | (2.01) | |
| Dry mid-altitudes | 38.78 | 41.21 | 43.46 | 41.17 |
| (3.78) | (3.47) | (3.15) | (1.99) | |
| Dry lowlands | 80.00 | 80.00 | 80.00 | 80.00 |
| (0.00) | (0.00) | (0.00) | (0.00) | |
| Highlands | 33.20 | 36.43 | 34.20 | 34.61 |
| (3.13) | (2.69) | (2.75) | (1.65) | |
| Average | 35.13 | 36.64 | 36.96 | 36.25 |
| (1.61) | (1.45) | (1.48) | (0.87) |
Note: Standard errors in parenthesis;
the standard errors are zero because FGD participants provided 80% loss for all data points.
Source: Community survey.
Fig 5Geographic distribution of average yield loss (%) due to FAW (2017–2019).
Estimated total maize production losses.
| MMEs | Loss (millions of tonnes) | Loss (millions of US$) | ||||
|---|---|---|---|---|---|---|
| 2017 | 2018 | 2019 | 2017 | 2018 | 2019 | |
| Wet upper mid-altitudes | 0.064 | 0.080 | 0.084 | 15.21 | 22.35 | 28.53 |
| Wet lower mid-altitudes | 0.007 | 0.004 | 0.006 | 1.52 | 0.89 | 1.73 |
| Dry mid-altitudes | 0.049 | 0.047 | 0.073 | 13.33 | 14.94 | 24.87 |
| Wet lowlands | 0.002 | 0.005 | 0.005 | 0.55 | 1.37 | 1.53 |
| Dry lowlands | 0.002 | 0.002 | 0.002 | 0.75 | 0.58 | 0.46 |
| Highlands | 0.057 | 0.089 | 0.095 | 14.22 | 25.24 | 32.28 |
| Total | 0.182 | 0.228 | 0.265 | 45.59 | 65.38 | 89.40 |
We use producer prices to estimate the value of production losses.
The exchange rate was 26.87 ETB/US$ in 2017, 27.43 ETB/US$ in 2018, and 29.23 ETB/US$ in 2019.
Source: Authors’ computation based on community survey and CSA’s agricultural sample survey.
Human health and environmental impacts of insecticides used to control FAW.
| Insecticides | Active ingredient (%) | Application rate (liter/ha) | Quantity (liters) | Components of field use EIQ | |||
|---|---|---|---|---|---|---|---|
| Average EIQ | Consumer effects | Producer effects | Ecological effects | ||||
| Malathion | 50 | 2 | 114,529 | 23.80 | 3.80 | 7.70 | 49.60 |
| Diazinon | 60 | 1 | 256,914 | 22.60 | 1.30 | 3.50 | 63.00 |
| Dimethoate | 40 | 1 | 25,488 | 11.50 | 3.90 | 3.50 | 26.90 |
| Chlorpyrifos | 48 | 0.5 | 60,496 | 5.50 | 0.40 | 1.20 | 14.90 |
Source: Authors’ computation based on MoA’s pesticides data [37].