Pest control in agriculture targeting insects, bacteria, fungi, and viruses appeared to be substantial for reducing economic disaster. While chemists held a place in the control of insects, pathologists shared their experience within the diversity of microbes. Following the division into annual and perennial crops, breeders and pathologists were under pressure to improve crops. Annual crops required more assistance of chemists, so we chose in this chapter to focus on perennials and innovative technologies based onto either genetics or genetic engineering. Long-term research on molecular virology and viral resistance has turned from the classical breeding techniques to genetic engineering. This chapter covers a combination of diversified technologies (classical breeding, virus detection and disease identification, molecular research, including natural gene identification and selection, and genetic engineering of virus resistance) that have emerged from pest control; their efficiency in perennials is discussed here.