PROTECTION OF SHADE TREES FROM INSECTS. 345 



soap dissolved in 5 gallons of water, or with kerosene (10 per 

 cent.) and water mixed and applied with a pump made especially 

 for the purpose. 



In the winter the belfries and towers of all public buildings 

 should be searched and the beetles found in them carefully 

 gathered up and burned. Vast numbers of them are often 

 found in such places. 



As the females of the canker worm and of the white-marked 

 tussock moth are wingless, trees may be protected against them 

 by putting sticky bands around the trunks of the trees. A 

 strip of tarred paper five inches wide, tacked around the tree 

 and covered with a quarter-inch layer of printers' ink, makes 

 a serviceable band. Cotton batting should be placed under the 

 paper to prevent insects from crawling beneath it. The ink 

 will harden after a few weeks, but may be kept soft and sticky 

 by brushing it over occasionally with black Virginia oil such as 

 is used for lubricating the axles of freight cars. The ink and 

 oil should not be spread on the bark of the trees. 



Several forms of metal protectors are on the market, but all 

 need frequent attention to keep them in good condition. All 

 forms of bands and protectors are unsightly and are not needed 

 where spraying is practiced. 



Remedies for Sucking Insects. All the sucking insects 

 that have been named above or that are liable to injure shade 

 trees must be destroyed by something that will kill by contact, 

 as they do not take the arsenical poisons into their system. 

 The cheapest and most efficient of these insecticides is kerosene 

 oil and water, but a pump of special pattern is necessary to 

 apply it. A mixture containing fifteen per cent, of kerosene 

 will kill most sucking insects without injury to the foliage of 

 the trees. One pound of whale-oil soap in five gallons of water 

 is also an efficient remedy. 



Remedies for Borers. Borers are more liable to attack trees 

 which have been weakened or injured than healthy and vigorous 

 specimens and often attack that portion of a tree where large 

 branches have been cut off in a careless way and decay has 

 begun. This form of attack is shown in Plate XIII, figure 13. 

 The maple borer, however, sometimes attacks strong trees. 

 Constant watchfulness will detect the borers when they begin 

 their work and they may then be destroyed by injecting carbon- 



