502 TwENTY-FlEST BlENNIAL EIePOET 



In a commercial orchard district even the family orchards have 

 to be sprayed to a certain extent, no matter v^hat the owner thinks 

 of it. The laws in most of the northwestern states provide that 

 where an orchard is infected with certain insects or d.iseases and 

 the owner refuses to spray and clean up his premises, the inspectors 

 have the power to do the work and it is charged up against the 

 owner and collected with his taxes. Even in the towns the trees 

 are sometimes so badly infested with scale that it is necessary for 

 the inspection service to provide power sprayers and spray the few 

 trees in the back yards. A man either has to take care of his fruit 

 trees or cut them down. If he refuses to remove them, the inspector 

 will, and that is also charged and collected the same as taxes. 



By far the most destructive disease the grower on the Pacific 

 Coast has to contend with is the Fire Blight of the apple and pear. 

 This is caused by a minute organism that lives in the inner bark 

 where no spray can reach it. The disease is confined almost ex- 

 clusively to pome fruit. The pear is supposed to be the most 

 susceptible, but in the Pacific Northwest, it is almost as destructive 

 in some varieties of apples as in the pear. 



The appearance is first noticed as blossom blight. The blossoms 

 wither away and the twigs and young leaves blacken and die as if 

 the orchard had been struck by fire, hence the name Fire Blight. In 

 many cases the disease goes no further than the blossom or fruit spur. 

 In others, and especially in some varieties, it goes on dovra. the limb 

 and may either kill the branch entirely or kill only a portion and 

 form what is known as canker. These cankers carry the disease 

 over winter. As soon as the sap starts to fiow in the spring a 

 sweetish liquid, containing myriads of the bacteria, is exuded from 

 these cankers. Bees Avill suck this juice and then fly to flower 

 clusters and inoculate them. Other insects also carry the disease, 

 but most of the blight is supposed to be transmitted by bees. How- 

 ever, aphis are fond of this juice and when they suck the sap from 

 the rapidly growing twigs or branches, may inoculate them with 

 the blight. 



One fertile source of inoculation is careless cultivators. The top 

 of the hame may strike a canker and later break the bark of a 

 healthy tree and allow the germs to enter. The bacteria cannot get 

 through the old bark except through a wound, but must be carried 

 into a blossom or through the soft, sappy, rapidly growing water 

 sprout. 



Blight spreads much worse in a rapidly growing orchard than 

 in one that is making little growth. Perhaps this is one of the 

 reasons it is so much more destructive in the orchards of the coast 

 where they have good cultivation than in ones that have not such 

 good care. Careless pruning has spread this- disease as much as 

 any one thing. The pruning tools may cut through a canker and 

 then inoculate healthy wood. If there is blight in an orchard, the 



