Tree spraying or tree pruning involves manually removing some branches of your tree that are encroaching on the shrubs. The reason for the removal is to prevent the new growth of pests and to beautify your shrubs. It is widely used by homeowners and commercial property owners all over the world, as they are one of the cheapest, easiest and fastest insect control methods. Tree spraying involves spraying the trees with various toxic substances in order to kill the pests and prevent them from growing again.
Tree felling and tree spraying are both parts of the broad spectrum of organic pest management practices. Tree felling involves killing the affected trees and spraying the soil where they grow. Tree spraying is similar to insecticide spray except that instead of killing insects and disease organisms, it is used to prevent further infestations. It is generally applied before or during the rainy season or cold weather in order to prevent the growth and spread of diseases.
-Jones Tree and Plant Care