University of Twente Student Theses
Assessing the relationship between outbreaks of the African armyworm and climatic factors in the forest transition zone of Ghana
Adama, Ibrahim (2011) Assessing the relationship between outbreaks of the African armyworm and climatic factors in the forest transition zone of Ghana.
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| Abstract: | The African armyworm Spodoptera exempta (Walker) is a migratory moth, the larvae (caterpillars) of which are important pests, particularly in sub-Saharan Africa. This moth species also demonstrates great variability in the extent and severity of infestation. As such it is considered a serious outbreak pest of cereal crops and grasslands in Africa. The African armyworm is known to cause extensive damage to maize crops and rangeland in the transition zone of Ghana. This research is an investigation of the relationship between the Normalized Difference Vegetation Index, rainfall and temperature and how they influence the outbreak of this moth species in the Ejura-Skyedumase district of Ghana. The temporal patterns of the variables and their interrelationships have been evaluated through graphical, logistic and standardization z-score transformations. A strong similarity between temporal patterns of vegetation index and rainfall has been established. Likewise, the temporal pattern of temperature runs opposite to NDVI and rainfall patterns. Standardized NDVI anomaly has revealed periods of low vegetation index with corresponding high wetness denoting damage to vegetation due to the activities of the insects during outbreak. This revelation is a confirmation of reports gathered from local famers. NDVI therefore is a good predictor of armyworm outbreaks since a relationship was established between the occurrences of the moth species and multi-temporal 10-day NDVI signal. The much hypothesized assertion that rainfall and temperature influence the occurrence of armyworms has also been dealt with by assigning some climatic variability likely to influence the occurrence of the moth species. Keywords: Armyworm, Spodoptera exempta, anomaly, outbreak, temporal pattern, relationship, NDVI, rainfall, temperature, multi-temporal, occurrence |
| Item Type: | Essay (Master) |
| Faculty: | ITC: Faculty of Geo-information Science and Earth Observation |
| Programme: | Geoinformation Science and Earth Observation MSc (75014) |
| Link to this item: | https://purl.utwente.nl/essays/93190 |
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