18 



The Forests op Maryland. 



height to be out of the reach of cattle, the ensuing damage, if any, will 

 be very slight, unless the soil itself is damaged by excessive pasturing. 

 This problem must, therefore, be solved by carefully weighing the 

 relative values of the woodlot for pasture or for wood production, and 

 the one which is least important must be sacrificed to the other. It 

 should be understood that they cannot be successfully combined, and 

 it is for the owner to decide between them. 



TREE DISEASES. 



There are a number of insects and fungous diseases affecting forest 

 trees, some of which have done an immense amount of damage locally 

 in recent years, and others which have been destructive at different 

 periods. It will not be possible within the limits of this report to treat 

 the subject with any amount of detail, but information regarding the 

 different diseases, their life histories, habits, and methods of control, 

 so far as they have been worked out, may be obtained in special publi- 

 cations issued by this Department or by the Federal Government.* 



Insect Injuries. 



The most important insects affecting forest trees are the Locust 

 Borer, the Locust Leaf Miner, the Two-Lined Chestnut Borer, and the 

 Pine Bark Beetle. None of these insects are of wide distribution in 

 the State and they have not done a very great amount of damage. 

 They may of course at any time increase to an alarming extent under 

 favorable conditions, but ordinarily they are held in cheek by natural 

 enemies or other adverse conditions. Mention is not made here of the 

 numerous insects which feed upon shade trees and often do great dam- 

 age ; though some of them attack the trees in the forest, they are not 

 sufficiently destructive to be classified and described as forest insects. 



The Locust Borer, Cyllene rohiniae, is found throughout the State, 

 but is most destructive in the central portion, where it attacks locust 

 trees of all sizes, boring into the wood, often honeycombing it, causing 

 the trees to have dead patches on the surface, and rendering them 

 liable to desti'uction in storms or by having branches broken off. Like 

 practically all other boring insects, they are difficult to reach and 

 little can be done toward their control. In sections where the Locust 

 Borer is at all destructive it is not advisable to plant locust, nor to 

 depend upon it as a forest tree. 



The Locust Leaf Miner, Odontota dorsalis, was partieularlj^ active 

 and widespread in Maryland during 1912-1915. Its work is charac- 

 teristically shown by the brown appearance of the foUage of locust 



• Samples of insects and fungi sent to the State Forester will, wherever possible, be 

 identified, and advice given as to methods of control. 



