Vexing viruses
Despite lack of direct chemical control products, there are ways to thwart viruses.
Plant viruses are pathogenic particles that cause damage inside plant cells by interfering with the allocation of resources that the plant has produced through photosynthesis. Once viruses get into plants, viruses shed their protein coats and begin using their RNA or DNA to induce the plant cellular machinery to produce more and more virus particles. The viruses then move systemically throughout the plant. Some viruses, such as tobacco mosaic virus (TMV), are mechanically transmitted, including our handling of infested plants and use of propagation tools. Other viruses are vectored by insects and other pests. Impatiens necrotic spot virus (INSV) is a serious disease of greenhouse crops in which the virus is vectored by the western flower thrips insect.