Bottle gourd, Lagenaria siceraria (Molina) Standley, is a top ranked important vegetable crop in Bangladesh. Recently, bottle gourd production in the north eastern part of Bangladesh has reduced greatly by the infestation of an invasive beetle species. This study is the very first report that confirmed the species as sap beetle, Epuraea sp. (Erichson) (Coleoptera: Nitidulidae) (Accession No: MW256489.1) by molecular barcoding. It was observed that Epuraea sp. has spread in all the four districts viz. Sylhet, Habiganj, Sunamgonj and Maulvibazar of the north eastern part of Bangladesh. This beetle caused the pollination failure in bottle gourd by consuming the pollens voraciously from the male flowers. Just after blooming of bottle gourd flowers, Epuraea sp. adults attacked the male flowers and fed almost all the pollens and also damaged the stamens. In severe cases these beetles also fed the pollens on the stigma of female flowers that carried by the other pollinators. The mean numbers of beetles per male and female flowers were 6.4 ± 1.02, 1.8 ± 0.37, 2.0 ± 0.44, 2.6 ± 0.55 and 1.6 ± 0.24, 0, 0, 1.4 ± 0.2 in Sylhet, Habiganj, Sunamgonj and Maulvibazar, respectively. Eventually, this infestation occurred 29.6 to 52.6% fruit setting reduction by this pest.