A Civic Enemy: TKe TussocK MotK" 



Prof. D. P. PenKallow, McGill University 



THE past year's discussion in the 

 press of Montreal, Toronto and other 

 cities, relative to the appearance 

 of the Tussock Moth, has directed atten- 

 tion to a matter of very great interest 

 to all cities where shade trees are re- 

 garded as of essential value. Among 

 the many insect enemies of our shade 

 trees, the Tussock Moth is one of the 

 worst, since it multiplies rapidly, and the 

 very large number of insects produced 

 by a single brood leads to the rapid de- 

 foliation of the trees upon which they 

 occur. Fortunately, as pointed out by 

 Dr. Fletcher, the danger here is not so 

 great as farther south, since with us 

 there is only one brood each year, while 

 in the northern states there are two 

 broods and in the southern states prob- 

 ably three broods in a season. This 

 difference is due to the fact that we are 

 situated near the northern limit of dis- 

 tribution, and it is therefore a much less 

 difficult matter to control the insect or 

 even to exterminate it if proper measures 

 are adopted. As an aid to human en- 

 deavor in this direction, birds and nat- 

 ural parasites constitute an important 

 element, but even under such conditions 

 it is possible for the insect to get beyond 

 control and to cause the most serious 

 damage to one of the most valuable 

 assets a city can have. 



That the Tussock Moth is not regarded 

 with indifference or allowed to be con- 

 trolled by its natural enemies, is evident 



Silver Maple Leaves Eaten by Larvae. 



In successive stages of growth from a (newly hatched larvae) to / (full 

 larvae). 



m the great care taken, and the large 

 cunt of money annually expended, 



r*THECANADiAN HORTICULTURIST has received 

 umber of requests for information regarding 



le Tussock Moth, which has done much damage 

 to shade trees in various Canadian cities during 

 the past summer. We have pleasure, therefore, 

 in reproducing this article with cuts from and 

 by permission j of The Canadian Municipal 

 Journal. 



by cities in the United States, for its ex- 

 termination. As the female does not 

 fly, the distribution is effected either by 

 the migration of the cater- 

 pillars from tree to tree in 

 search of food, or by their 

 transport on vehicles, animals 

 or people upon whom they 

 may fall from trees. It there- 

 fore follows that when the 

 insects are found in a restrict- 

 ed area, it 'is possible to con- 

 fine them there, if prompt and 

 efficient measures be taken. 

 In winter and early spring 

 the eggs ma}^ be readily de- 

 tected and destroyed either 

 by picking and burning, or by 

 the use of creosote oil which 

 is far more expeditious and 

 economical. But if the eggs 

 are allowed to hatch, which 

 they will do about the first of 

 May, the situation becomes a 

 much more difficult one to 

 deal with, as then the only 

 effective remedy is to be 

 found in spraying, a process 

 which will not only involve 

 expensive apparatus but the 

 expenditure of much time and 

 labor, with the result that 

 extermination will not be as 

 effective and complete. 



There is only one way to deal with 

 such a problem, and that is to take 

 prompt and efficient meas- 

 ures at the time when a 

 minimum of labor and ex- 

 pense will be demanded. The 

 indifference which leaves 

 such matters to the natural 

 course of events in the hope 

 that the difficulty may right 

 itself, is not justified Isy any 

 policy of good municipal 

 government. 



Shade trees are among the 

 most valuable assets a city 

 can have. They not only 

 add a great element of 

 beauty and general attract- 

 iveness to otherwise barren 

 stretches of pavement and 

 dwellings, but they contrib- 

 ute to the actual health and 

 moral tone of the commti- 

 nity in ways which are too 

 numerous and too well known to re- 

 quire restatement here. The mere fact 

 that in all the most cultured and 

 enlightened communities of the world, 

 streets are provided with trees at 

 great cost and maintained with great 

 care, is in itself sufficient proof that they 

 are esteemed beyond the ordinary stand- 

 ards of pecuniary value. But from a 



275 



merely monetary point of view, a well- 

 grown tree is worth anywhere from $100 

 toj$500 according to its kind and size. 



The White-Marked Tussock Moth 



Orgyiti leucostigma. u, larva; &, female pupa; c.malepupa; d.e.male 

 moth; /. female moth; g, same ovipositing; h, egg mass; i, male cocoons; 

 k, female cocoons, with moths carrying eggs. 



It is, therefore, not inappropriate to 

 urge in the most insistent manner, that 

 our cities should take efficient measures 

 for the better care of its trees, and that 

 it should not allow such pests as the 

 Tussock Moth to work unchecked. 



Protect the Birds 



Our birds deserve protection and en- 

 couragement. Some birds, the robins, 

 for instance, do destroy some few small 

 fruits during a short season in the year, 

 June and July; but the amount of fruit 

 they save, in the destruction of insects 

 throughout the whole year, is of infinitely 

 greater moment. The robins' appetite 

 for insects is never satisfied; and the 

 fruit grower should ignore his slight 

 depredations on cherries and other 

 fruits in the light of his greater benefits. 



However, there is an easy and de- 

 sirable means of saving even this small 

 amount of fruit that the birds eat, and 

 that is to supply them with something 

 still more desirable in their eyes. The 

 Russian mulberry tree looks well and 

 bears heavily, while the birds prefer 

 the berries to any of our small fruits. 

 If these trees were liberally planted 

 throughout the country, the fruit would 

 be saved for commercial purposes, and 

 the birds for insect destroyers. 



