86 SHADE TKEES. 



leaves and succulent shoots, and so exhaust their vitality. 

 When they become abundant the honey dew ex- 



Maple louse. -,-,-, -, 



creted by them sometimes covers the leaves with 

 a sticky secretion that may be abundant enough to drop to 

 the street below. This secretion tends to clog the foliage so 

 that it may drop while yet perfectly green, and a black soot 

 fungus is also likely to develop. Fortunately this sort of 

 attack does not continue after the first spell of hot dry 

 weather, and during a normal season is not apt to be bad 

 at all. 



Remedial Measures. 



As against plant lice of all kinds on shade trees, nothing is 

 much better than whale-oil soap suds and this applies not 

 whaie-oii on ^y ^0 those species that attack the leaves but 

 soap - to some that gather along the undersides of 



branches of conifers. In general, 1 pound in 4 gallons of 

 water is an effective strength, and safe on most kinds of 



foliage. 



INSECTS INJURING CONIFERS. 



Pines and other conifers are not often used as street trees, 

 but are not infrequently found in parks and grounds around 

 residences. They suffer from a variety of insects and are 

 not easily treated, because they are extremely sensitive to 

 most insecticides. Against feeders upon the leaves, arsenate 

 of lead is the only arsenical poison that can be 

 safely used. When plant lice attack them, 

 whale-oil soap suds, one pound in six gallons of water, lib- 

 erally applied, will be safe and reasonably effective. Against 

 those woolly species that are frequently found massed against 

 the underside of the branches, a forcible jet of water is often 

 very satisfactory or the whale-oil soap may be used, 1 pound 

 in 4 gallons of water, locally applied. If the trees are suf- 

 ficiently valuable, simply scrub the branches with a stiff 

 brush and weak soap suds. 



