Occurrence, distribution and control of papaya mealybug, Paracoccus marginatus (Hemiptera: Pseudococcidae), an invasive alien pest in Sri Lanka

Abstract

A hitherto unrecorded species of mealybug was discovered in early 2008 in the western provincial districts Colombo and Gampaha in Sri Lanka, infesting a large number of plant species. Investigations were done to identify the pest and to study its host range, nature of damage and distribution, and to design and implement control measures. The pest was identified as papaya mealybug, Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae), an invasive alien species originating from Mexico and/or Central America. The mealybug found to heavily infest more than 40 plant species including papaw, the major host, and several horticultural and floricultural crops like Plumeria, manioc, bread fruit, Alstonia macrophylla and Jatropha spp. By 2009 the pest had spread to other parts of the country including the North Western, Saba ragamuwa, Southern, North Central, Central and Eastern provinces. As an immediate control measure, im idacloprid 200SL, thiamethoxam 25%WG and Mineral oil were recommended for the control of this pest until biological control agents could be introduced