94 



TWENTY-EIGHTH FRUIT-GROWERS' CONVENTION. 



FRUIT-FLIES AND THEIR. EXCLUSION. 



By ALEXANDER CRAW, of San Francisco, 

 Deputy State Commissioner of Horticulture, and Horticultural Quarantine Officer. 



The term "fruit-fly" has been given to a group of dipterous (two- 

 winged) insects that deposit their eggs upon fresh fruits while the latter 

 are nearly or quite ripe and still hanging upon the tree or attached to 

 the plant, and on this account are considered the most troublesome 

 pests the horticulturists have to contend with in countries where they 

 are indigenous, or to which they have been unfortunately introduced. 



Repeatedly we have had to burn up importations of infested citrus 

 and deciduous fruits entering the State. To be on the safe side we admit 

 no fruit liable to contain their maggots. 



One of the first fruit-flies to demand our attention was the " Morelos 

 orange worm." This pest is supposed to be a native of the State of 

 Morelos, about one hundred miles south of the City of Mexico. From 

 its location we had little to fear from its introduction into California, 

 until railroads began to penetrate and traverse that country, giving 

 rapid transit to perishable fruits and thus carrying the pest to other 

 sections, until now it is to be found in nearly every State of Mexico; 

 and in referring to it we have discarded the name "Morelos orange 

 worm," and use a broader term and call it the " Mexican orange maggot" 

 ( Trypeta ludens). 



When oranges began to reach the Eastern States from Morelos we 

 took immediate steps to prevent their introduction into California, and 

 wrote to the heads of the Mexican railway companies not to receive any 

 oranges for shipment into this State, and were assured that none would 

 be. We also communicated with the United States officials of the Agri- 

 cultural Department, at Washington, D. C, regarding the advisability 

 of placing quarantine officers to guard against the introduction of such 

 fruit by rail; but in the absence of a Federal law, nothing could be done, 

 and those points are still open. When Acapulco and several other 

 Mexican Pacific Coast districts became infested, infested oranges and 

 sweet limes began to reach us by sea in the possession of passengers and 

 crews on vessels from there, also as freight, and were promptly destroyed 

 by burning, as no dipping or fumigation could be relied upon to destroy 

 the maggot. In preserving the maggots for the cabinet and to send as 

 specimens to the various County Boards of Horticulture in the orange- 

 growing districts of the State, we used 95 per cent alcohol and found 

 they lived from eleven to forty- two minutes therein. Such vitality is 

 probably owing to the fact that in that stage of their existence they live 

 in a solution of citric acid. 



When the State Board of Horticulture adopted such radical measures 

 to prevent the entry of such a pest into the orange groves of the State, 



