104 



THIRTY-FOURTH FRUIT-GROWERS ' CONVENTION. 



Ill order to secure a comprehensive and at the same time thorough 

 knowledge of the distribution of the different citrus pests in this great 

 Southern California citrus belt, as well as to determine the extent to 

 which fumigation is practiced, and its efficacy in different districts, the 

 months of August, September, and October were spent in examining 

 citrus groves from Santa Barbara to Chula Vista, including the counties 

 of Santa Barbara, Ventura, Los Angeles, San Bernardino. Riverside. 

 Orange, and San Diego. 



Much information of value relative to our subject Avas secured during 

 these travels, and the hearty cooperation advanced, as well as services 

 rendered by the various county horticultural commissioners, county 

 inspectors, and fruit growers with whom I came in contact, made my 

 travels indeed a path of pleasure as well as of duty. The earnestness 

 of these men in their duties, together with their broad knowledge of 

 their profession, easily explains why the horticulture of Southern Cali- 

 fornia has reached its present high degree of perfection. 



The prevalence of noxious scale pests throughout this southern citrus 

 belt (with few exceptions, notably that of interior San Bernardino 

 County) , and their subsequent effect on the tree and fruit, demand the 

 attention of the fruit grower who would make his crop a most success- 

 ful one. The recent researches in fruit transportation, conducted by Mr. 

 G. H. Powell, .of the United States Bureau of Plant Industry, inform 

 us .that the percentage of decay in shipment is greater in washed than 

 unwashed fruit, all other factors being equal. To obviate the necessity 

 of washing leads to the introduction of fruit into the packing house in 

 a clean condition. This can be accomplished largely through the -control 

 of those scale pests which cause the dirty fruit. 



There are three methods most commonly resorted to in this State for 

 the control of the scale pests of the citrus. These are fumigation, spray- 

 ing, and beneficial insects. It is unnecessary for us to mention the 

 efficacy of each of these different practices — suffice to say, that fumi- 

 gation has come to be relied upon far more generally in Southern 

 California than any other one practice. Since its discovery in 1887. 

 fumigation with hydrocyanic acid gas has grown so greatly in favor 

 that to-day it is generally practiced in all the more important scale- 

 infested districts of Southern California, as well as in other parts of 

 the world. Hand in hand with the widespread use of this gas, an 

 evolution of fumigation methods and equipment has taken place. The 

 cumbersome apparatus of the earlier days has dropped into disuse, and 

 been replaced by simplified forms. 



In the first dosage system published, that of ]\Iorse. in 1887. dosage 

 A\'as estimated in proportion to the height of the tree, being based 

 apparently on the contents or space represented when the tree was 

 enclosed by a tent. For a tree 6 feet high ]\Iorse gave the equivalent 

 of 1 ounce of cyanide ; for a tree 20 feet high the equivalent of 36 

 ounces. Plis dosage throughout for trees from 6 feet in height to those 

 20 feet in height averaged practically % of an ounce of cyanide per 

 hundred cubic feet space enclosed. 



In 1888 Coquillett gave forth his dosage system, which also applied 

 to trees from 6 to 20 feet in height. The dosage throughout this table, 

 as has been deteriiiined by computation. v\'as so calculated as to pro- 

 duce a gas of practically the same strength for large trees as for small. 



