(iVPSV AM) BROWN-TAIL MOTHS. [Jan. 1908. 



priations will be continued from this source until all danger from the 

 rapid spread of these pests is overcome, and everything has been done 

 that man's ingenuity can dc\ ise and nature's forces can accomplish 

 to reduce the 1 gypsy and brown-tail moths to the rank of such common 

 native pests as tin- tent-caterpillars, tussock moths, canker-worms and 

 elm-leaf beetle. Tlioe native insects have their ])eriods of increase and 

 decrease. or " ups and d<i\vns." at longer or shorter intervals. 



Massachusetts must not expect too much from the extensive and well- 

 directed efforts now hein- made to introduce the natural native enemies 

 of the gypsy niid brown-tail moths i'rom other countries where they 

 are intermittent pests, due in part to their insect enemies, but also to 

 conditions of environment developed through centuries of nature's 

 changes. While remarkable results have already been obtained in suc- 

 cessfully introducing many thousands of Europe's insect foes into the 

 colonies of these pests in America, and while there is evidence that these 

 enemies are breeding here, it may be several years before they make a 

 noticeable impression upon their hosts. The people of Massachusetts 

 must not look for a sudden and wholesale slaughter of these pests by 

 their little European foes. 



The work of finding and introducing these natural enemies is being 

 successfully and thoroughly carried on by careful, conscientious and 

 expert workers, at a minimum expense to Massachusetts. The more 

 thoroughly I investigated this work, the more I became convinced that 

 it was being well done, and the less 1 could find to criticise. If the final 

 results prove of little value in helping to control these pests, it will not 

 be because the work of scouring the earth for their natural enemies and 

 I'ntrnducini;- them was not thoroughly and successfully accomplished. 

 This extensive experiment of attempting to control an insect pest with 

 other insects brought i'rom its native homes in various parts of the 

 world will prove one of the greatest object lessons in economic ento- 

 mology. It must be considered a success from an entomological stand- 

 point, even if these little foes do not succeed in conquering their hosts. 

 Several entomologists are employed by the Hawaiian government to 

 scour the earth for insect enemies with which to light insect pests in 

 the islands. But the federal entomologist. Mr. YauDine, who has spent 

 -cvrral years at the experiment station at Hawaii, and who is thus 

 familiar with the conditions there and the work being done with these 

 natural enemies, lias well diagnosed the situation (hero in the following 

 sentence: "The introduction of such beneficial species will, when they 

 become established, help to solve the problem of Hawaii's insect pests, 

 but cannot be relied upon to exterminate the pests, or render the use of 

 insecticides unnecessary." So far as we know, no serious insect pest 

 has ever been exterminated by its natural enemies, even when aided 

 by man's ablest efforts \\ilh insecticides. The most that Massachusetts 

 can hope for from the introduction of the enemies of the gypsy and 

 brown-tail moths is that they will materially help in controlling these 

 pests. Extermination by these little foes is impossible. 



