Managing disease and insect pests has evolved over the years. When I first became a certified arborist in the mid seventiessprays were still applied on a calendar schedule using pesticides with long lasting chemical residues left on the plant. Everything on the property was treated.  This was more than a decade after Rachel Carson's "Silent Spring" was published. Understanding the life cycles of disease pathogens and insect pests and targeting treatments only when thresholds are met are goals of an Integrated Pest Management (IPM) program. Using non-chemical products such as oils, soaps or biologicals is the preference. A chemical treatment is only used when there is no alternative. IPM succeeded in agriculture in the late seventies and early eighties greatly reducing the use of pesticides and saving the farmers a lot of money. In the mid to late eighties IPM techniques and concepts were adopted in the care of the urban forest. At first the cost of managing cost more than calendar sprays. This was because it required more visits on a property to monitor for insect populations and disease conditions. The nineties brought the concept Plant Health Care (PHC) to the urban forest. Plant Health care is a politically correct way of saying Integrated Pest management. It manages insect and disease problems with pesticides as a last resort. Unfortunately tall trees still had to be sprayed and non target trees and properties were still exposed to spray drift. Throughout the nineties injection technolgies for tree pest managemnt improved. Ninety foot trees could now be treated to manage insects or disease without any drift. The products stayed inside the plant and moved systemically throughout protecting the plant from significant damage. This was fantastic but expensive. Since the milenium the injection technology has improved and is more affordable. New environmentally products have arrived. Some products can be injected into the root systems pf trees and shrubs and delive long lasting management. In 2020 there is no need for a tree or landscape company to spray pesticides on your tall trees that can drift on non taget trees and properties