178 Seventeenth Annual Report of the 



cellars and shops where imported stock was handled were made 

 and all trimmings were carefully collected and burned. Early in 

 January we found that wherever infested stock was unpacked in 

 a warm room, the larvae would leave their nests and not return as 

 they do in the open. They would soon cover themselves with their 

 silken threads wherever they found lodgment. 



To discover and burn all nests required a very careful seedling- 

 to-seedling inspection, especially with branched or bushy plants. 

 Even the roots needed to be looked into for any nest or portion of 

 nests that might have been torn off and dropped into them. The 

 custom of packing seedlings not tied in bundles, placed tops and 

 roots in layers, caused a distribution of nests through the boxes 

 containing from 3,000 to 15,000 seedlings each. All such inspec- 

 tion was comparatively simple until we found the habits of the 

 escaped caterpillars and an inch-to-inch inspection was pursued. 

 At this stage, of course, careful fumigation of all stock with 

 hydrocyanic acid gas appeared feasible, but to our disappointment 

 we found that the use of a formula of 4- to 5 times such as is used 

 for San Jose scale, together with much longer time exposure, was 

 ineffective. The young larvae were not all killed. With more 

 time and many more experiments we do not find yet that fumiga- 

 tion can be relied on. All stock from boxes in which nests were 

 found were ordered dipped in miscible oil at portions of 1 to 20. 

 This proved effective. 



In the mass of reported shipments that came to our office while 

 we were receiving daily reports of the discovery of a large number 

 of insects by our inspectors, we at the same time had knowledge of 

 large shipments of imported stock to nearly every slate in the 

 Union and to the Dominion of Canada. 



Certainly, we could not permit the establishment of brown-tail 

 moths to the southwest and north of us. Therefore, in accord- 

 ance with the useful custom of the members of the American 

 Association of Official Horticultural Inspectors, we sent a state- 

 ment of our findings to each inspector in the States and the 

 Dominion and also called attention to the apparent inefficiency of 

 fumigation to destroy the tiny caterpillars. 



This statement of information was followed by a prompt report 

 to each state inspector on this continent of all shipments of which 



