38 AGRICULTURE OF MAINE. 



trunks of your trees about a week before the leaves fall, or 

 even at the present date would catch a lot of the wingless fe- 

 males as they ascend the trunks to deposit their eggs. 



In dealing with both the tent caterpillar and canker worm 

 one should always remember that all insects are most easily 

 poisoned when they are young, so, for ordinary outbreaks of 

 them, spray thoroughly from one to five days before the 

 blossoms open. 



Oyster Shell Scale. 



This is one of our most common scale insects and frequently 

 does quite serious damage to young trees. It is a single brooded 

 insect passing the winter as an egg under the old female scale. 

 About the time the blossoms fall these eggs hatch and four or 

 five days later the young lice, now white, crawl out from under 

 the old scale and scatter over the trees, in a day or so settling 

 down and inserting their beak or sucking tube into the bark of 

 the tree, there to stay during the remainder of their lives. A 

 scale is soon secreted and assumes the familiar oyster shell 

 shape and turns to a dark brown in color. In the fall the eggs 

 are deposited by the female under the scale which has pro- 

 tected her during her life and there they remain sheltered for the 

 winter. The most common recommendation for this insect is 

 dormant spraying with lime and sulphur and I have no doubt 

 but that your dormant or blister mite spray helps to a great 

 extent in controlling it. 



I have seen quite a lot of dormant spraying for oyster shell 

 and have never seen any that appeared really satisfactory. 

 Where the spray has to penetrate or tear off a scale and then 

 destroy a mass of eggs, it seems unreasonable that dormant 

 spraying should be expected to control it perfectly. 



The best remedy in a bad infestation is to spray as soon as 

 the young lice are all out and crawling over the trees and 

 before they have had time to grow a protective scale over their 

 backs. Most writers recommend black leaf 40. or kerosene, or 

 oil emulsion for this spray ; but I have seen perfect results from 

 the use of summer strength lime sulphur and I should recom- 

 mend, where oyster shell is present in any quantity, the retard- 

 ing of the ordinary codling moth spray until the young lice 

 crawl. You will get little reduction in your effect on codling 



