Characterization, Distribution and Risk Assessment of the Invasive Papaya Mealybug (Hemiptera: Psuedococcidae) in Kwale, Mombasa and Kilifi, Kenya

Abstract

Papaya mealybug is a serious pest of papaya in South America. In Africa, the pest was first reported in West Africa in 2009. The objectives of this research were to confirm the identity of a pest of papaya mealybug description, which was devastating papaya in Kilifi, Kwale and Mombasa Counties in Kenya; through morphological and molecular characterization, establish its distribution and assess its risk in current and future climatic conditions. Live mealybugs were collected still attached on plants and others in 85% ethanol, transported to Kenya Plant Health Inspectorate Service (KEPHIS) and the International Centre of Insects Physiology and Ecology (Icipe) laboratories for morphological and molecular analysis. Morphological analysis was carried out in two ways, useful characteristics were observed on the mealybugs on plants, while specimens in ethanol were mounted on slides and observed under microscope while running through a taxonomy key. Molecular analysis involved DNA extraction, Polymerase Chain Reaction, Gel electrophoresis, sequencing, BLASTing and phylogenesis. Distribution and risk assessment was determined by running occurrence and environmental data in Species Distribution Models., Maximun Entropy (MaxENT) and Genetic Algorithm for Rule‐set Prediction (GARP). Morphological analysis confirmed the pest positive for Paracoccus marginatus. Molecular analysis confirmed very high similarity of the samples with a Chinese, Paracoccus marginatus sample in the GenBank, National Center for Biotechnology Informatio (NCBI). MaxENT and GARP established very high-risk areas of papaya mealybug establishment with current and future climatic conditions in Kenya.