You can use standard pheromone traps and also add some kairomone to enhance the results. Here are references:
Christine E. Miluch, Lloyd M. Dosdall, Maya L. Evenden, The potential for pheromone-based monitoring to predict larval populations of diamondback moth, Plutella xylostella (L.), in canola (Brassica napus L.), Crop Protection, Volume 45, March 2013, Pages 89-97, ISSN 0261-2194, http://dx.doi.org/10.1016/j.cropro.2012.11.023.
Nofemela, R. S. (2010). The ability of synthetic sex pheromone traps to forecast Plutella xylostella infestations depends on survival of immature stages. Entomologia Experimentalis Et Applicata, 136(3), 281-289.
Pengyan Li, Junwei Zhu, and Yuchuan Qin. 2012. Enhanced Attraction of Plutella xylostella (Lepidoptera: Plutellidae) to Pheromone-Baited Traps with the Addition of Green Leaf Volatiles. Journal of Economic Entomology 105 (4), 1149-1156
Dear sir have you any research paper on Diamondback Moth Rearing/Natural control/ Biological control? if you have any related Research paper kindly attach it with the response Thanks.