166 



THE GARDEN MAGAZINE 



November, 1911 



The workings of a boring insect (leopard moth in 

 silver maple). See what havoc the cut uncovered! 



always follow neglected wounds or the 

 work of unskilled pruners. The cavity 

 may be small and not important of itself, 

 but as a possible breeding place for insects 

 and fungi, it demands serious consideration. 

 The accumulation of moisture and the 

 exclusion of light and heat, characteristic 

 of every cavity, are the very conditions 

 that the spores of a fungus disease seek. 

 The weakened vitality of the tree, resulting 

 from the fungus together with the de- 

 cayed wood, then invite the entrance of 

 many injurious insect pests, so that within 

 a comparatively short time serious injury 

 will result to the whole tree. If the disease 

 has not traveled far and the cavity is small, 

 a timely cleaning (by cutting back to sound 

 wood) and filling will prevent the entrance 

 of fresh insects and fungi. 



Every bit of decayed and discolored 

 wood must be removed by the free use of 

 the knife, chisel or gouge. It is far better 

 to enlarge the cavity by cutting out every 

 bit of diseased wood than to leave a 

 smaller hole in an unhealthy state. And 

 it may surprise you how far the diseased 

 tissue will run. 



If boring insects are within the cavity 

 they must be destroyed before the filling 

 is put in, either by cutting out bodily with 

 the knife or suffocating by an injection of 

 carbon bisulphide into the burrows. When 

 the cavity is absolutely cleared, cover its 

 interior with a coat of white lead paint, 

 which acts both as a disinfectant and helps 

 to hold the filling. The cavity is then 

 solidly filled with stone and cement. The 

 cement is used in mixture with two-thirds 

 fine sand and not only serves as a bed for 

 the stone but also forms the outer wall of 

 the filling. The exposed face of the filling 



must not be brought out to the same plane 

 as the outer bark of the tree, but should 

 recede a little, so that the growing tissue 

 or cambium which is situated immediately 

 below the outer bark, can grow over the 

 cement and cover the whole cavity (if it 

 be a small one), or grow out sufficiently 

 to overlap the filling and hold it as a frame 

 holds a picture. 



In many cases, mere gouging out of the 

 decayed material without the filling will 

 best serve the purpose. This is true of 

 all shallow perpendicular wounds caused 

 by bruised bark. In such cases the bruised 

 bark should be removed; it will never 

 adhere to the tree again. Then cut smooth 

 the rough edges and cover the exposed wood 

 with coal tar. Coal tar has an antiseptic 

 as well as protective influence. It becomes 

 absorbed by the wood of the tree to a 

 depth of an eighth to a quarter of an inch, 



Where the chisel and gouge alone will serve the pur- 

 pose better than filling 



and destroys every fungus spore with which 

 it comes in contact. Tar is preferable to 

 paint for wound dressing, not only because 

 of its penetrating and antiseptic qualities 

 but also because it lasts longer and never 

 peels off in later years. 



Bandaging wounds with burlap or cloth 

 is hurtful to the tree, because beneath the 

 bandage fungus spores find ideal con- 

 ditions for development. Wherever I have 

 seen a bandage applied to a tree wound, 

 I have invariably found disease on the 

 wood underneath. Discard all bandages! 



If it is an insect that infests your trees, 

 observe its habits — whether it feeds by 

 chewing the leaves, by sucking the sap 

 from the leaves and twigs, or by boring 

 into the wood. The choice of the remedy 



will greatly depend on the method of 

 feeding. Insects fall into three groups 

 according to their way of feeding: 



Chewing insects (Group i), such as elm 

 leaf beetle and tussock moth, are de- 

 stroyed by spraying the foliage with arse- 

 nate of lead andparis green. Four pounds 

 of arsenate of lead and three ounces of 

 paris green to forty gallons of water will 

 be a suitable mixture. 



The sucking insects, scales or lice (Group 

 2), are killed by spraying or washing (de- 

 pending on the habit and life stage of the 

 insect) with a solution of whale oil soap or 

 kerosene emulsion or some of the commer- 

 cial miscible oil emulsions, or other prepara- 

 tions specially designed for plant lice, all of 

 which act externally on their bodies, smoth- 

 ering or stifling them. Care is required in 

 the use of these solutions, presupposing 

 a knowledge of the insect and its habits, the 

 strength of the solution and the time of 

 application. 



The boring insects (Group 3) are killed 

 by injecting carbon bisulphide into the 

 burrow and clogging the orifice immediately 

 with putty or soap, or in some cases (espe- 

 cially fruit trees) by cutting out the insect 

 with a knife. 



Certain trees in special localities may 

 require special and radical treatment. 

 Thus if your chestnut trees are dying from 

 the fungus which has killed almost all the 

 chestnut trees in the vicinity of Greater 

 New York; or if your hickory trees are 

 commencing to die (see the October Gar- 

 den Magazine, page 109), the only thing 

 is to cut them down and burn. 



Finally, after all "treatment" is done, 

 look to better growing conditions — culti- 

 vate the soil around the trees to a distance 

 proportionate to the spread of the branches 

 and apply some fertilizer in the fall and 

 again in the early spring. 



ML 





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A diseased wound where a filling is justified 





