Population Density and Distribution Pattern of Mites Infesting The Invasive Plant, Bidens Sulphurea Cav.

Population density and distribution pattern of the major groups of mites infesting an invasive plant, Bidens sulphurea Cav. were studied during the period of January, 2013 to September, 2013 covering three districts of Kerala viz. Malappuram, Palakkad and Thrissur. Random samples of leaves were collected from mite infested plants of B. sulphurea growing in various localities, based on visual symptoms. Individual leaf was thoroughly screened under a stereomicroscope to record the species diversity, nature of infestation, distribution pattern etc. of the associated mites. Results of the study revealed the association of both phytophagous and predatory mites on the plant. The phytophagous mites recovered during the study included members of 3 families viz. Tenuipalpidae, Bryobiidae and Tetranychidae while the predatory mites belonged to the family Phytoseiidae. A general abundance of tenuipalpid mites was recorded on the plant, irrespective of geographical variation. The family Tetranychidae was found represented by two genera viz. Tetranychus and Eutetranychus while the remaining families were found to comprise of a single genus each. Most of mite species preferred the lower surface of the leaves and in cases of severe infestation, the upper surface of the leaves was also found invaded by a few species. The paper also discusses on the population density and distribution pattern of individual mite species on B. sulphurea.