India is a country where three-fourths of the population works in agriculture. Farmers grow various plants in their fields depending on the environment and other resources at their disposal. To attain high productivity and outstanding quality, however, some technical know-how is needed, coupled with technological support. The percentage of disease produced in crops is more important than any other factors for efficient and fertile plant cultivation. The solution is to use a camera to take pictures of the input, and a machine learning technique to process them. Once the illness or disease of leaf, stem, or plant is identified, turn on sprayer to spread the specific pesticide over the exposed region; at the same time, display the exposed area and predict the cures. This is very important—otherwise the insecticide cannot be sprayed effectively. It becomes a win–win situation for the farmer as this can be handled from anywhere without having to work in the field covered with pesticides. Precision agriculture can be achieved with variable spray technology (VST). It offers both technological advancement and broader application scope from its inception compared to other approaches in last 5 years. This article elucidates introduction, characteristics, and evolution of VST for multiple criterion such as target identification, automatic controller, and spray applications.