1. A dsRNA for controlling infestation of a plant with an insect, the dsRNA comprising a polynucleotide sequence comprising at least 140 bp and being about 85% to about 100% complementary to a segment of a target gene of the insect, wherein the target gene is a proteasomal beta-subunit gene having the coding sequence as set forth in SEQ ID NO: 3 or SEQ ID NO: 317; and wherein when the dsRNA is topically applied or injected into plants and the plant is ingested by said insect, mortality and/or stunting of said insect is instigated.