Influence of climatic factors on the abundance and spread of the Papaya mealybug, Paracoccus marginatus (Hemiptera: Pseudococcidae) in southwestern Nigeria
NJE Vol. 42(1) : 45-56, 2026
DOI.10.36108/NJE/6202/24.0140
Larayetan A.A1,2, Adedire, C.O2, Umeh V.C,3 and Goergen G.4
1 Department of Biotechnology, Kogi State University Kabba, (KSUK) Nigeria.
2Department of Biology, Federal University of Technology Akure, (FUTA) Nigeria.
3 National Horticultural Research Institute, Idi-ishin Ibadan, (NIHORT) Nigeria.
4International Institute of Tropical Agriculture (IITA), Benin Station, Cotonou, Benin
Abstract
This study assessed how weather variables shape the population dynamics and infestation intensity of the papaya mealybug, Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae), on papaya across three agro-ecological zones in southwestern Nigeria—Akure (Rainforest), Ogbomoso (Guinea savannah), and Ibadan (Derived savannah)—from January to December 2016. Monthly field assessments showed no significant differences (p > 0.05) in infestation intensity or mealybug counts between leaves and fruits across the zones. August, the wettest month (266.43 mm rainfall), had the lowest insect percentage (7.5%), whereas March recorded the highest percentage population (57.94%) on both leaves and fruits; infestation levels followed the same pattern. Relative humidity was negatively associated with both infestation (r = −0.392, N = 36, P = 0.018) and population (r = −0.426, N = 36, P = 0.010). Although some months differed significantly (p < 0.05) in infestation and population, overall variation was linked to intra-annual weather (rainfall, relative humidity, and temperature) rather than to the agro-ecological zone. These results indicate that seasonal climatic conditions, particularly high rainfall and relative humidity, suppress P. marginatus abundance and damage, independent of site-level ecological differences.
Keywords: Carica papaya, Abiotic factors, papaya mealybug, Paracoccus marginatus