OKCHAKD MANAGEMENT. 121 



131. The Tent Caterpillar. On young apple-trees the 

 ring or cylinder of eggs covered with waterproof varnish 

 can easily be detected, detached, and burned during the 

 leafless period of winter. If any escape it is far better to 

 twist out the nests with a forked stick than to burn them 

 out, as often practised with kerosene, which always injures 

 the bark and leaves. 



The rodents and insects noticed at this time the 

 orchard ist comes first in contact with in orchard manage- 

 ment. A few of the leading insects encountered later will 

 be discussed in the chapter on spraying. But we now 

 have special books on spraying copiously indexed that can 

 be used at the nick of time when exact information is 

 needed to guide the work of insect extermination or con- 

 trol. 



132. Orchard Fertilization. In the Eastern and South- 

 ern States, and on the west coast, the commercial fertil- 

 izers have been used freely in orchards with continued 

 culture. The result has been that the expression "Fer- 

 tilizer sick" has come into use. The evident trouble in 

 such cases is lack of humus in the soil and a changed 

 mechanical condition of the soil. What is needed is a 

 mingling of the humus and nitrogen of cover-crops, and 

 a judicious application of potash and phosphoric acid. 

 Even on the rich prairie lands of the West the soil is 

 deficient in potash. After an orchard has borne repeated 

 crops, and the spread of tops does not favor the sowing 

 of catch-crops, the free use of barn-yard manure is advis- 

 able at least once in four years. The summary that will 

 apply to all soils and all parts of the Union is that the 

 orchard must have humus in the soil from cover-crops or 

 manure, with an ample supply of nitrogen, potash, and 

 phosphoric acid. 



133. Low Hedge for Shelter-belt. Stock should in all 



