16 



locilitios the loss is almost total. Garcia records, from check trees 

 in sDraving experiments, that the loss varied from 67 to 99 per cent. 

 There are many localities in this zone in both east and west where 

 apples can l)C gTOwn, but on account of the injuries due to the codling- 

 moth other crops are grown instead. 



IMMUNE REGIONS. 



In many regions of the Far West one often hears the fruit growers 

 sav that on act-ount of the peculiar climatic conditions of that region 

 apples are free from injury and the codling moth <-an not exist. 

 Aiuono- these climatic conditions quoted are dense fogs, mountam 

 breezel and comparatively high altitudes. Seven or eight years ago it 

 was thought that the Hood River Valley was immune from the insect; 

 the same was thought of the Pajora Valley in California; but ater 

 developments have shown that immunity was due to the tact that the 

 insect had not been introduced into those localities. It has also been 

 said that there was no codling moth near the coast m Oregon, but 

 Professor Cordley finds that it is present in some localities and 

 believes that the former immunity was due to isolation. 



In many restricted areas in the Pacific Northwest more or less 

 isolated the codling moth is either absent or present in such small 

 numbers that it has not been observed. From past experience and 

 examination of these localities it is evident that the insect in its gen- 

 eral spread has not vet reached them. It is a question whether or 

 not the insect will l>e injurious in these localities, but it is certain ha 

 it can be present. The writer has no hesitancy in concluding that 

 there is no region in the Pacific Northwest in which apples are 

 crrown in which the codling moth can not exist. „ , , 



Manv causes of immunity by isolation in river valleys have been 

 noted. ^ The most marked case is at Mr. I. B. Pernne's orchard at 

 Blue Lake, Idaho. The nearest orchard is 18 miles distant down 

 Snake River, while there are no orchards in the other direc-tion inside 

 of 75 to 80 miles. This orchard was free from codling moth mitil 

 three or four years ago, the larva, having undoubtedly been intro- 

 duced in old apple boxes about that time. 



MEANS OF SPREAD. 



There are several ways in which the codling moth can be distributed 

 The most prolific source of distribution comes from the shipping ot 

 fruit from an infested region. Fruit which contains the larva insects 

 m be shipped great distances, and when the larv. complete tl^r 

 growth thev spin cocoons, and in due time the moths emerge, and 

 |:i:: unerri;g\nstinct seek the nearest apple trees. Many an^a^ 

 found to have spun their cocoons in the angles and cracks of the boxes 



