Molecular typing of mealybug Phenacoccus solenopsis populations from different hosts and locations in Punjab, India

True identity and existence of genetic variability in mealy bug from different regions holds immense significance for adopting appropriate control measures along with predicting the development of any biotypes. Mealy bug, Phenacoccus solenopsis adults were collected from four host plants i.e., Gossypium hirsutum--cotton (C), Abelmoschus esculentus--okra (O), Pennisetum glaucum--Napier Bajra (B) and a weed--Parthenium hysterophorus (P) in five cotton growing districts i.e., Abohar, Bathinda, Mansa, Muktsar and Faridkot of Punjab state. Variability among different populations was investigated through comparative analysis of four different RAPD markers. The genetic similarity dendrogram established that irrespective of the host plant and the collection site, 20 mealybug populations were distinguishable into two major clades that were related to each other by 68%. Clade 1 included populations from Abohar district; it also included a single population each from Muktsar and Bathinda districts. The populations from all the other districts were grouped under Clade 2 with genetic similarity of 78% Even under Clade 2, individual populations appeared to exist in location specific sub-clades. Thus, there is great possibility of development of biotypes which may differ in resistance to insecticides and host plant specificity.