Abstract
Sitophilus zeamais is a primary pest of stored maize, which can cause quality and quantity losses. Maize is cultivated in several West African countries where different agro-climatic and agro-ecological conditions exist. These conditions could influence the Sitophilus zeamais morphology. Thus, the purpose of this study is to identify the Sitophilus zeamais morphological groups in the four countries. This was carried out through the morphometric study of 30 male Sitophilus zeamais individuals taken from the yellow maize in each country, by measuring with a binocular magnifying glass, 16 variables of the different tagmas belonging to the insect. Subsequently, statistical analyses were firstly carried out with the raw measurements, such as the principal component analysis, in order to extract the contribution of the variables on each factorial axis and to visualise the correlations between the variables. Taking the case of the transformed measurements, in addition to the principal component analysis, a discriminant factorial analysis was carried out to find out the best factor for gathering individuals according to their morphology, a confusion matrix to summarise the individual’s reclassification in order to deduce the good and bad classification rates, and an ascending hierarchical classification which consists of gathering the individuals according to their similarity and separating them according to their dissimilarity using the truncation method. Therefore, five morphological groups were identified. However, the existence of these morphological groups would not be linked to agro-ecological, climatic conditions and to the geographical remoteness between countries.
Highlights
Maize (Zea mays, Poaceae family) is a cereal cultivated alone or with several crops in various agro-ecological zones [1]
Taking the case of the transformed measurements, in addition to the principal component analysis, a discriminant factorial analysis was carried out to find out the best factor for gathering individuals according to their morphology, a confusion matrix to summarise the individual’s reclassification in order to deduce the good and bad classification rates, and an ascending hierarchical classification which consists of gathering the individuals according to their similarity and separating them according to their dissimilarity using the truncation method
Estimating the losses caused by the S. zeamais is most of the time difficult because of its high variability, which can be explained by the agro-ecological conditions, the harvest period [2] [5] and even by the maize variety [2] [6]
Summary
Maize (Zea mays, Poaceae family) is a cereal cultivated alone or with several crops in various agro-ecological zones [1]. Maize is infested in the field and during its storage by insect pests such as the Sitophilus zeamais (Motschulsky) This primary pest of stored maize can cause qualitative and quantitative losses [2] and encourage the colonisation of stocks by secondary pests and toxin-producing fungi such as the Aspergillus flavus [3]. The environmental factors, including agronomic practices (types of fertilisers, cultivation practices), influence the grain composition [9], the morphology and even the genetics of the insect population that infests the maize, as noted in the case of Caryedon serratus [10] This context led us to ask whether the S. zeamais has the same morphology in the different West African agro-ecological areas where maize is cultivated in important quantities. In order to answer this scientific issue, the objective of this study will be to determine the existence of the S. zeamais morphometric groups in West Africa
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call