The papaya mealybug Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae) is native to Mexico and/or Central America (Miller et al. 1999) and was first described in 1992. This species was recorded for the first time in Tamil Nadu, during July, 2008 in Coimbatore district ( which is considered to be invasive) on papaya and also on many ornamental plants in the household and up to December,2008 it was restricted to Coimbatore district and subsequently spread to neighbouring districts. Survey was conducted immediately throughout the state of Tamil Nadu to study the extent of damage and spread of the invasive mealybug, P. marginatus. Severe infestation (80 to 90 %) was observed on the crops viz., papaya, mulberry, tapioca, brinjal, tomato, bhendi and flower crops.
|Reasons faster spread of Mealybug|
A white wax and flour-like substance around the body of the pest is the reason for not able to control this pest easily. This pest spread rapidly due to lack of natural enemies of these pests and it is a foreign originated insect. Also, Reproduction of this mealybug is 15 times a year. It is also more capable of laying. An insect lays between 500 and 600 eggs a year. The population is growing at a higher level, thus causing great damage.
Since, July 2008, a sudden outbreak of papaya mealy bug, Paracoccus marginatus (Williams and Granara de Willink) was noticed in papaya, mulberry, tapioca, jatropa, vegetables, fruits, cotton, plantation crops, spices and flowers including several weeds in different parts of Tamil Nadu. Mass multiplication technology of the exotic parasitoid Acerophagus papayae (Noyes and Schauff) was standardized for large scale laboratory production of parasitoid involving host insect culture, parasitoid production techniques, storage, transportation, adult diet requirement and method of release. Mass multiplication of mealybug parasitoids was immediately taken up in TNAU in Agricultural and Horticultural colleges, 36 research stations and 14 Krishi Vigyan Kendras on a war footing manner and the effective parasitoid viz.,Acerophagus papayae was released throughout Tamil Nadu. About 6.25 million parasitoids viz., Acerophagus papayae (Noyes and Schauff) were mass multiplied and released in the farmers field @ 100 parasitoids / field / village or block in more than 2500 villages at free of cost throughout Tamil Nadu. A spectacular control of papaya mealy bug during 2010, with imported parasitoid A. papayae is an example of successful classical biocontrol programmes carried by this department in which an amount of Rs 435 crores loss per annum is saved in Tamil Nadu on papaya, mulberry and tapioca, and an amount of Rs 244.5 crores was benefited annually by not recommending chemical pesticides.