Submitted in partial fulfillment of the requirements for the degree of Master of ArtsText from page 1: The San Jose scale is the most serious insect pest of the Missouri orchards. It is capable of killing young fruit trees in two or three years and old trees become unprofitable and succumb to the attack in a few years if unsprayed. It has been Widely spread over almost every county in the state. The scale is a dangerous pest on account of its rapid multiplication and inconspiouous spread which enables it to entirely cover the bark, leaves and fruit of the tree within a few years. It seriously infests nearly all kinds of fruit trees and many ornamental plants. No other insect pest has received more attention or has had more written or said a...