| Outbreak and Control of Papaya Mealy Bug (Paracoccus marginatus) in India
Papaya mealy bug Paracoccus marginatus is an invasive pest. The pest was first observed in Coimbatore in Tamil Nadu during 2008 on Papaya crop. Rapid spread of P. marginatus among agricultural and horticultural crops of economic importance was noticed. The pest assumed serious status across many economically important and horticultural crops of Tamil Nadu followed by its spread to the adjoining States of Kerala, Karnataka, Andhra Pradesh, Maharashtra and subsequently in Tripura and Odisha. The pest emerged as a serious threat to a number of crops such as Papaya (Carica papaya L; Caricaceae), Mulberry (Morurs alba L; Moraceae), Jatropha (Jatropha curcus L; Euphorbiaceae), Tapioca (Manihot esculenta Crantz; Euphorbiaceae), Shoes flower (Hibiscus-rosa-sinensis L; Malvaceae), and Guava (Psidum guajava L; Myrtaceae). In addition, other annual crops such as Cotton (Gossypium hirsutum; Malvaceae), Brinjal (Solanum melongena L; Solanaceae), Red gram (Cajanus cajan; Leguminaceae) and Tomato (Lycopersicon esculentum L ; Solanaceae) were affected.
The pest is invasive, and has a wider host range. It was necessary to take up immediate steps to manage it in the places of occurrence to limit the yield and crop losses. Insecticidal treatment against this pest has proved futile in most places. Therefore, three species of exotic parasitoids effective against the papaya mealy bug were imported from Puerto Rico, and mass multiplied under quarantine at National Bureau of Agriculturally Important Insects (NBAII), Bengaluru. These three species of exotic parasitoids are Anagyrus loecki (Noyes and Menezes), Acerophagus papayse (Noyes and Schauff) and Pseudleptomastrix mexicana (Noyes and Schauff) (Hymenoptera: Encyrtidae). The field releases of these parasitoids gave effective control of the pest in the affected areas. Mass multiplication techniques of these parasitoids in laboratory and field were developed by NBAII. The parasitoids are being supplied to the farmers of affected areas for the control of Papaya mealy bug. A training programme on mass multiplication of these parasitoids was also organised by NBAII for scientists/officials of Krishi Vigyan Kendras (KVKs), State Agriculture Universities (SAUs) and Central Integrated Pest Management Centers (CIPMCs).
A strategy for promoting bio-control along with survey and surveillance programme has been adopted for the suppression of this potential pest. Inoculative releases of exotic parasitoids are expected to provide successful pest suppression in India. Creation of awareness through wider publicity across the affected States will avoid the risk of further crop loss and pest spread. Plucking of infested plant parts and keeping them in cages for conservation of naturally occurring bio-control agents may also be useful for the control of this pest.
At present there is no report of serious pestilence due to this pest and the pest is below economic threshold level in all the areas where pest is reported in India. It took five months to suppress this pest effectively through classical biological control.