Population Dynamics of the Mango Mealybug Rastrococcus invadens Williams (Homoptera: Pseudococcidea) in Western Burkina Faso

Abstract

Aims: The study aimed at determining the periods of high pest population of the mango tree mealybug Rastrococcus invadens Williams with respect to biotic and abiotic factors. Study Design: Semiweekly observations were performed on the mango trees with a view of assessing the density of alive, dead or parasitized R. invadens. Place and Duration of the Study: This study was conducted in Western Burkina Faso from May 2014 to April 2015. Methodology: A set of mango trees was selected in each of the following locations: Toussiana, Bérégadougou and Orodara. The assessment was conducted on 20 leaves (five leaves per cardinal point) that were picked up from each mango tree at each observation date. The parasitized mealybugs were kept inside pill boxes for two weeks and the emerging parasitoids were collected and kept in alcohol 70°. Data were registered and processed with the Microsoft Excel 2010 and SPSS software. Results: Results showed that R. invadens’ populations were more abundant during the wet season (May-September 2014) than the dry season (November 2014-April 2015) in all study locations. In general, parasitism was low. Some peaks of abundance were recorded in both wet and dry seasons. The evolution of the mortality of the insect pest was the same in all locations and peaks were observed from December 2014 to April 2015. The density of living R. invadens was significantly correlated with temperature and relative humidity. Impact of the parasitism due to Anagyrus mangicola Noyes and Gyranusoidea tebygi Noyes were also assessed and discussed. Conclusion: Periods of R. invadens populations’ abundance are well known in Western Burkina Faso. The parasitoids A. mangicola and G. tebygi are well established. The level of parasitism could be improved by releasing of A. mangicola and G. tebygi to control R. invadens efficiently.