scholarly journals Uncertainties In The Effectiveness of Biological Control of Stem Borers Under Different Climate Change Scenarios In Eastern Africa

2021 ◽  
Author(s):  
Ines Gwendolyn Jendritzki ◽  
Henri E. Z. Tonnang ◽  
Paul-André Calatayud ◽  
Christian Borgemeister ◽  
Tino Johansson ◽  
...  
Keyword(s):  
Climate Change ◽  
Biological Control ◽  
Insect Pests ◽  
Maize Yield ◽  
Stem Borer ◽  
Eastern Africa ◽  
Climate Change Scenarios ◽  
Agricultural Crop ◽  
Yield Losses ◽  
Stem Borers

Abstract Climate change (CC) is expected to significantly affect biodiversity and ecosystem services. Adverse impacts from CC in the Global South are likely to be exacerbated by limited capacities to take adequate adaptation measures and existing developmental challenges. Insect pests today are already causing considerable yield losses in agricultural crop production in East Africa. Studies have shown that insects are strongly responding to CC by proliferation, shift in distribution or by altering their phenology, which is why an impact on agriculture can also be expected. Biological control (BC) has been proposed as an alternative measure to sustainably contain insect pests but few studies predict its efficacy under future CC. Using the species distribution modelling approach Maxent, we predict the current and future distribution of three important lepidopteran stem borer pests of maize in eastern Africa, i.e., Busseola fusca (Fuller, 1901), Chilo partellus (Swinhoe, 1885) and Sesamia calamistis (Hampson, 1910), and two of their parasitoids that are currently used for BC, i.e., Cotesia flavipes (Cameron, 1891) and Cotesia sesamiae (Cameron, 1906) . Based on these potential distributions and data collected during household surveys with local farmers in Kenya and Tanzania, future maize yield losses are predicted for a business-as-usual scenario and a sustainable development scenario. Accordingly, we found that BC of the three stem borer pests by C. flavipes and C. sesamiae will be less effective under more severe CC resulting in a reduced ability to curb maize yield losses caused by the stem borers. These results highlight the need to adapt BC measures to future CC to maintain its potential for environmentally-friendly pest management strategies. The findings of this research are thus of particular relevance to policy makers, extension officers and farmers in the region and will aid the adaptation of smallholder agricultural practices to current and future impacts of CC.

scholarly journals Farmers’ Perceptions of Rice Production Constraints and Stem Borers Management Practices in Tanzania

2018 ◽  
Vol 10 (6) ◽  
pp. 57 ◽  
Author(s):  
Bonaventure January ◽  
Gration M. Rwegasira ◽  
Tadele Tefera
Keyword(s):  
Management Practices ◽  
Insect Pests ◽  
Group Discussion ◽  
Stem Borer ◽  
Rice Production ◽  
Stem Borers ◽  
Access To Credit ◽  
Cultural Methods ◽  
Rice Stem Borers ◽  
Rice Ecosystems

Rice farmers in Tanzania continue to experience losses due to stem borers. However, the information on farmers’ knowledge and perceptions of rice stem borers is limited and farmers’ efforts on managing this insect have been ineffective. The aim of this study was to investigate constraints affecting rice production and farmers’ approaches of stem borer management in irrigated low land rice ecosystems in Tanzania. Research method: A focus group discussion with farmers using a semi-structured questionnaire was used for data collection. The information collected included: farmers’ socio-economic profiles, farm characteristics, knowledge and perceptions of stem borers and their management practices.Farmers reported insect pests such as stem borers, white flies, leaf rollers and grasshoppers as major constraints of rice production. Other constraints reported were such as diseases, damage by birds, drought, weeds and lack of access to credit for purchasing inputs. Most of the farmers apply chemical insecticides against rice insect pests particularly stem-borers where number of health hazards have been reported. Very few farmers use cultural methods including crop residue disposal and split application of nitrogenous fertilizers for reduction of stem borer damages. The study revealed that, most farmers have limited knowledge on the recommended stem borer management practices and suggests that environmentally friendly pest management methods to be designed and implemented to minimize losses associated with rice stem borers.

scholarly journals Assessment of Climate Change Impact on Crop yield and Evaluation of Coping Strategy using Crop Growth Simulation Model

2020 ◽  
Vol 15 (1) ◽  
pp. 106-122
Author(s):  
J. Alam ◽  
R. K. Panda
Keyword(s):  
Climate Change ◽  
Grain Yield ◽  
Simulation Model ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Co2 Concentration ◽  
Maize Yield ◽  
Crop Growth ◽  
Climate Change Scenarios ◽  
Area Index

 Any change in climate will have implications for climate-sensitive systems such as agriculture, forestry and some other natural resources. Changes in solar radiation, temperature and precipitation will produce changes in crop yields and hence economics of agriculture. It is possible to understand the phenomenon of climate change on crop production and to develop adaptation strategies for sustainability in food production, using a suitable crop simulation model. CERES-Maize model of DSSAT v4.0 was used to simulate the maize yield of the region under climate change scenarios using the historical weather data at Kharagpur (1977-2007), Damdam (1974-2003) and Purulia (1986-2000), West Bengal, India. The model was calibrated using the crop experimental data, climate data and soil data for two years (1996-1997) and was validated by using the data of the year 1998 at Kharagpur. The change in values of weather parameters due to climate change and its effects on the maize crop growth and yield was studied. It was observed that increase in mean temperature and leaf area index have negative impacts on maize yield. When the maximum leaf area index increased, the grain yield was found to be decreased. Increase in CO2 concentration with each degree incremental temperature decreased the grain yield but increase in CO2 concentration with fixed temperature increased the maize yield. Adjustments were made in the date of sowing to investigate suitable option for adaptation under the future climate change scenarios. Highest yield was obtained when the sowing date was advanced by a week at Kharagpur and Damdam whereas for Purulia, the experimental date of sowing was found to be beneficial.

scholarly journals Economy-Wide Effects of Climate Change in Benin: An Applied General Equilibrium Analysis

2019 ◽  
Vol 11 (23) ◽  
pp. 6569 ◽  
Author(s):  
Femi E. Hounnou ◽  
Houinsou Dedehouanou ◽  
Afio Zannou ◽  
Johanes Agbahey ◽  
Gauthier Biaou
Keyword(s):  
Climate Change ◽  
General Equilibrium ◽  
Crop Yield ◽  
National Level ◽  
Import Demand ◽  
Equilibrium Analysis ◽  
Household Welfare ◽  
Climate Change Scenarios ◽  
Yield Losses ◽  
Poor Households

This research analyzes the economic effects of climate change-induced crop yield losses in Benin. As agriculture is a large sector in Benin, the climate change-induced crop yield losses are expected to affect the entire economy as well as household welfare in both rural and urban areas. The paper applies a dynamic general equilibrium model and simulates productivity shocks in the agricultural sector derived from climate change scenarios for Benin. The findings show that climate change-induced crop yield losses reduce domestic agricultural outputs by 4.4% and the nonagricultural output by 0.9% on average by 2025. While export supply decrease by 25.5%, import demand increases by 4.9% on average by 2025. As price of labour and capital decline, household income drop for all household groups by 2.5% on average. Ultimately, household welfare decline for all household groups by 2.7% on average. Rural and particularly poor households are projected to experience the worst adverse effects of climate change-induced crop yield losses. The results show that without adaptive strategies to cope with climate change, economic growth and household welfare will decline even further by 2035 and 2045. Subsequently, the paper suggests that adaptation strategies are needed not only at the national level to overcome the projected negative effects on macroeconomic indicators, but also at household level to enhance the adaptative capacity of households, especially the poor households living in rural areas.

Insect pests and management technologies in dryland wheat in Washington

1996 ◽  
Vol 11 (2-3) ◽  
pp. 104-107
Author(s):  
K. S. Pike ◽  
L. K. Tanigoshi
Keyword(s):  
Biological Control ◽  
Seed Treatment ◽  
Insect Pests ◽  
Conservation Tillage ◽  
Cropping Systems ◽  
Wheat Yield ◽  
Yield Losses

AbstractSix species of ophids (Homoptera: Aphididae) are the most economically significant insect pests of wheat in Washington. Management technologies under development or in use in Washington emphasize biorational approaches, including development and use of resistance germplasm, manipulation of pest populations through cropping systems, and development of biological controls. We review wheat yield losses caused by aphids, their biological control, and the effects of conservation tillage and systemic seed treatment.

scholarly journals Simulated Impacts of Climate Change on Surface Water Yields over the Sondu Basin in Kenya

2016 ◽  
Vol 4 (8) ◽  
pp. 161-173
Author(s):  
Stephen Kibe Rwigi ◽  
Jeremiah N. Muthama ◽  
Alfred O. Opere ◽  
Franklin J. Opijah ◽  
Francis N. Gichuki
Keyword(s):  
Climate Change ◽  
Surface Water ◽  
River Basin ◽  
Assessment Tool ◽  
Swat Model ◽  
Eastern Africa ◽  
Fourth Generation ◽  
Climate Change Scenarios ◽  
Time Step ◽  
Impacts Of Climate Change

Potential impacts of climate change on surface water yields over the Sondu River basin in the western region of Kenya were analysed using the Soil and Water Assessment Tool (SWAT) model with climate input data obtained from the fourth generation coupled Ocean-Atmosphere European Community Hamburg Model (ECHAM4) using the Providing Regional Climates for Impacts Studies (PRECIS) model. Daily time step regional climate scenarios at a spatial grid resolution of 0.44Ëš over the Eastern Africa region were matched to the Sondu river basin and used to calibrate and validate the SWAT model.Analysis of historical and projected rainfall over the basin strongly indicated that the climate of the area will significantly change with wetter climates being experienced by 2030 and beyond. Projected monthly rainfall distribution shows increasing trends in the relatively dry DJF and SON seasons while showing decreasing trends in the relatively wet MAM and JJA seasons. Potential changes in water yields resulting from climate change were computed by comparing simulated yields under climate change scenarios with those simulated under baseline conditions. There was evidence of substantial increases in water yields ranging between 88% and 110% of the baseline yields by 2030 and 2050 respectively. Although simulated water yields are subject to further verification from observed values, this study has provided useful information about potential changes in water yields as a result of climate change over the Sondu River basin and in similar basins in this region.

scholarly journals Quantifying Agroforestry Yield Buffering Potential Under Climate Change in the Smallholder Maize Farming Systems of Ethiopia

2021 ◽  
Vol 3 ◽  
Author(s):  
Abel Chemura ◽  
Amsalu Woldie Yalew ◽  
Christoph Gornott
Keyword(s):  
Climate Change ◽  
National Level ◽  
Climate Change Impacts ◽  
Farming Systems ◽  
Maize Yield ◽  
Agroforestry System ◽  
Climatic Conditions ◽  
Yield Losses ◽  
Climate Regulation ◽  
Maize Yields

Agroforestry is a promising adaptation measure for climate change, especially for low external inputs smallholder maize farming systems. However, due to its long-term nature and heterogeneity across farms and landscapes, it is difficult to quantitatively evaluate its contribution in building the resilience of farming systems to climate change over large areas. In this study, we developed an approach to simulate and emulate the shading, micro-climate regulation and biomass effects of multi-purpose trees agroforestry system on maize yields using APSIM, taking Ethiopia as a case study. Applying the model to simulate climate change impacts showed that at national level, maize yield will increase by 7.5 and 3.1 % by 2050 under RCP2.6 and RCP8.5, respectively. This projected increase in national-level maize yield is driven by maize yield increases in six administrative zones whereas yield losses are expected in other five zones (mean of −6.8% for RCP2.6 and −11.7% for RCP8.5), with yields in the other four zones remaining stable overtime. Applying the emulated agroforestry leads to increase in maize yield under current and future climatic conditions compared to maize monocultures, particularly in regions for which yield losses under climate change are expected. A 10% agroforestry shade will reduce maize yield losses by 6.9% (RCP2.6) and 4.2 % (RCP8.5) while 20% shade will reduce maize yield losses by 11.5% (RCP2.6) and 11% (RCP8.5) for projected loss zones. Overall, our results show quantitatively that agroforestry buffers yield losses for areas projected to have yield losses under climate change in Ethiopia, and therefore should be part of building climate-resilient agricultural systems.

scholarly journals Field assessment of corn yield losses and compensatory yield for infested plants by Lepidopteran stem borers in different sowing dates at El-Behiera governorate, Egypt.

2020 ◽  
Vol 13 ◽  
pp. 31-40
Author(s):  
Al-Eryan M. A. S ◽  
Abu- Shall Amany M. H. ◽  
Ibrahiem H. K. ◽  
Huessein Hanaa S.
Keyword(s):  
Total Yield ◽  
Maize Yield ◽  
Simple Linear Regression ◽  
Yield Losses ◽  
Stem Borers ◽  
Yellow Corn ◽  
Maize Varieties ◽  
Increase Rate ◽  
Economic Injury

Whenever the determination of yield loss and economic injury levels are essential tools for initiating integrated pest management (IPM) programs in the maize field, the assessment of compensatory yield is very important for determinate the accurate losses in the field and the recovery power for the maize verity. The present study aimed to estimate the yield losses of three maize varieties due to Sesamia critica and Ostrinia nubilalis, infestation; regression between maize yield losses and percent of infestation and determine the compensatory yield arising in intact plants as a result of absence or dead (caused by infestation) of adjacent plants under field conditions in El-Behiera governorate. The present results showed that yield losses resulting from S. cretica infestation in early sowed maize ranged from 5.29 – 32.17%. In case of maize that sowed in recommended date “June”, yield losses due to S. cretica was slightly decreased, and it accompanied with O. nubilalis infestation in two fields, which increased the total yield losses. A simple linear regression turned out between the percentage of infestation of S. cretica or O. nubilalis and percentage of yield losses, with R2 values 0.84 and 0.45, respectively. The yellow corn was more tolerant to stem borers infestation than white corn with percentages of increase rate in compensatory yield 27.07 %.  Whenever the determination of yield loss and economic injury levels are essential tools for initiating integrated pest management (IPM) programs in the maize field, the assessment of compensatory yield is very important for determinate the accurate losses in the field and the recovery power for the maize verity. The present study aimed to estimate the yield losses of three maize varieties due to Sesamia critica and Ostrinia nubilalis, infestation; regression between maize yield losses and percent of infestation and determine the compensatory yield arising in intact plants as a result of absence or dead (caused by infestation) of adjacent plants under field conditions in El-Behiera governorate. The present results showed that yield losses resulting from S. cretica infestation in early sowed maize ranged from 5.29 – 32.17%. In case of maize that sowed in recommended date “June”, yield losses due to S. cretica was slightly decreased, and it accompanied with O. nubilalis infestation in two fields, which increased the total yield losses. A simple linear regression turned out between the percentage of infestation of S. cretica or O. nubilalis and percentage of yield losses, with R2 values 0.84 and 0.45, respectively. The yellow corn was more tolerant to stem borers infestation than white corn with percentages of increase rate in compensatory yield 27.07 %.  

Assessment of irrigated maize yield response to climate change scenarios in Portugal

2017 ◽  
Vol 184 ◽  
pp. 178-190 ◽  
Author(s):  
Chenyao Yang ◽  
Helder Fraga ◽  
Wim Van Ieperen ◽  
João Andrade Santos
Keyword(s):  
Climate Change ◽  
Maize Yield ◽  
Yield Response ◽  
Climate Change Scenarios

Relationships of intercropped maize, stem borer damage to maize yield and land-use efficiency in the humid forest of Cameroon

2005 ◽  
Vol 95 (5) ◽  
pp. 417-427 ◽  
Author(s):  
A. Chabi-Olaye ◽  
C. Nolte ◽  
F. Schulthess ◽  
C. Borgemeister
Keyword(s):  
Land Use ◽  
Cropping Systems ◽  
Maize Yield ◽  
Stem Borer ◽  
Percentage Increase ◽  
Mixed Cropping ◽  
Stem Borers ◽  
Humid Forest ◽  
Land Use Efficiency ◽  
Use Efficiency

AbstractStem borers are the most important maize pests in the humid forest zone of Cameroon. Field trials were conducted in the long and short rainy seasons of 2002 and 2003 to assess the level of damage and yield reductions caused by stem borers in monocropped maize and in maize intercropped with non-host plants such as cassava, cowpea and soybean. The intercrops were planted in two spatial arrangements, i.e. alternating hills or alternating rows. All intercrops and the maize monocrop were grown with and without insecticide treatment for assessment of maize yield loss due to borer attacks. The land-use efficiency of each mixed cropping system was evaluated by comparing it with the monocrop. The temporal fluctuation of larval infestations followed the same pattern in all cropping systems, but at the early stage of plant growth, larval densities were 21.3–48.1% higher in the monocrops than in intercrops, and they tended to be higher in alternating rows than alternating hills arrangements. At harvest, however, pest densities did not significantly vary between treatments. Maize monocrops had 3.0–8.8 times more stems tunnelled and 1.3–3.1 times more cob damage than intercrops. Each percentage increase in stem tunnelling lowered maize grain yield by 1.10 and 1.84 g per plant, respectively, during the long and short rainy season in 2002, and by 5.39 and 1.41 g per plant, respectively, in 2003. Maize yield losses due to stem borer were 1.8–3.0 times higher in monocrops than in intercrops. Intercrops had generally a higher land-use efficiency than monocrops, as indicated by land-equivalent-ratios and area-time-equivalent-ratios of >1.0. Land-use efficiency was similar in both spatial arrangements. At current price levels, the net production of mixed cropping systems was economically superior to controlling stem borers with insecticide in monocropped maize. The maize–cassava intercrop yielded the highest land equivalent ratios and the highest replacement value of the intercrop. At medium intensity cropping this system is thus recommended for land-constrained poor farmers who do not use external inputs such as fertilizer and insecticides.

Sign in / Sign up

Export Citation Format

Share Document