Food Host Preference and Life cycle characteristics of the Papaya mealybug, Paracoccus marginatus Will. and Granara de Willink in Ibadan, Southwest Nigeria

Abstract

Papaya mealybug, Paracoccus marginatus is an invasive polyphagous hemipteran that causes enormous damage to different host plants in Nigeria. However, information on the pest’s damage potential and host range is scanty; therefore, the host preference and life cycle of P. marginatus were investigated. Six economic plants: Carica papaya (Caricaceae), Solanum lycopersicum (Soalnaceae), Manihot esculenta (Euphorbiaceae), Abelmoschus esculentus (Malvaceae), Psidium guajava (Myrtaceae) and Tectona grandis (Lamiaceae) were evaluated as food hosts to P. marginatus using free-choice and no-choice tests in screen cages (1.80×0.60×1.50m). The developmental biology was investigated following standard procedures at ambient conditions of 27±20C; 70±5% RH and 12:12 hour photoperiod. Significantly more P. marginatus migrated to and utilized C. papaya (27.5±2.9) and M. esculenta (20.75±1.3) as food host. This pest occurred on other plants in decreasing order; S. lycopersicon (17.0±1.3) > P. guajava (12.5±0.4) > A. esculentus (11.8±1.2) and T. grandis (10.00±1.4) appeared to be the least preferred. The duration of development from egg to adult ranged from 23.52±0.1 to 25.76±0.4 days in the females and 25.91±0.6 to 30.62±0.8 in the males, which passed through more nymphal instars (4) than in females (3). The life cycle of P. marginatus was completed in shorter time on C. papaya than on any other host plants. The differences between male and female adult weights (2.98±0.4mg and 3.90±0.6mg) were not significant. Paracoccus marginatus preferred pawpaw and cassava to the other crops. This information is useful for development of appropriate integrated management programme for the pest.