Biochemical characterization of culturable bacterial endosymbionts of papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae) from papaya plants

Abstract

Papaya mealybug, Paracoccus marginatus is a polyphagous pest with wide host range and reported to cause heavy economic loss upon infestation. Use of chemicals was found to be ineffective in controlling this exotic pest. The best alternative to control the pest is by means of biocontrol management strategies. Microorganisms, mostly bacteria were found to be in symbiotic relationship with several insects and they play a key role in the growth and development of the insects. In the present study, twenty six culturable bacterial endosymbionts of papaya mealybug viz., 7, 10, 3 and 6 from LB, R2A, NB and TSA media were isolated and characterized biochemically (carbohydrate fermentation, IMViC tests [Indole production, Methyl red, Voges-Proskauer test, and Citrate utilization test] and starch hydrolysis). Based on the results, the isolated gut bacteria were tentatively identified as Bacillus, Burkholderia, Serratia, Escherichia and Pseudomonas.