INTRODUCTORY. 31 



been found in isolated orchards this year, so that undoubtedly 

 thev were brought in return packages. 



file discovery made in various sections of the country this 

 Sprincr (1883), of the presence in young orchards of the San 

 Jose s'cale {A. vemiciosm) is sufficient proof that the nursery 

 stock was infested when bought. . , . j 



The presence of the codhn moth in an isolated apple orchard 

 in San Diego County, can readily be accounted for by the 

 owner carrying home his groceries in empty apple boxes that 

 were shipped to San Diego with infested fruit. 



The presence of the red scale {A. aurantii) in some orchards 

 in Southern California is attributed to the importation of two 

 or three young trees from Australia. 



The presence of the cottony cushion scale (/. purchcm) can 

 be charged to importation. . . . 



The codlin moth was brought in an importation ot hve bar- 

 rels of apples from States east of the Rocky Mountains, about 

 1878 The grain weevil (C. granana) and other injurious 

 species of the weevil family {curmUomdse) can readily be spread 

 in grain and plant seeds. 



CHAPTER VIIL 



Notes on Experimental Work. 



It is not only a duty, but a necessity, that every cultivator 

 of the soil, irrespective of the line of industry in which he is 

 en-ac^ed if his premises are infested or hkely to be infested by 

 in^ec't pests, that he should use his utmost efforts in experi- 

 mental work to find the best and cheapest methods for their 

 extermination, or for preventing their spread at least. In the 

 course of such experimental work, should he think he had 

 made an important discovery, he should be gmded by the 



following rules : . • u + 



1 It is well worth the care of any one who wishes to 

 be sure-as every one should-of conferring a benefit upon his 

 fellows rather than risk doing them an injury, to delay the 

 expression of results of experiments until the correctness ol 

 their results are tested by repeated trials. 



