June, 15] 



SEVERIN-SEVERIN: KEROSENE TRAPS 



331 



The solution was prepared by dissolving the brown sugar through a 

 cheese-cloth bag in cold water so as to strain out all foreign material 

 including ants, which in the Hawaiian Islands frequently gnaw through 

 the paper sacks containing the sugar. The mixture was thoroughly 

 agitated by pumping the liquid back upon itself with a common, 

 garden, brass spray-pump. This pump was provided with a rose 

 sprinkler nozzle which throws a mist-like spray (PL 13). 



To determine the effectiveness of the poisoned bait spray as a means 

 of controlling the Mediterranean fruit-fly under Hawaiian conditions 

 the following plan of procedure was adopted. For a period of five 

 weeks, ten kerosene traps were wired to the branches of citrus trees 

 of an orchard containing about four hundred orange, lemon, grape- 

 fruit, banana, fig, guava, papaia, peach, pear, pepper, plum and mango 

 trees. No spray was applied to any of the trees and vegetation in the 

 orchard during this period and exact data were kept concerning the 

 number of fruit-flies and beneficial insects found dead in the oil traps. 

 During the following five weeks, the poisoned bait was sprayed once 

 a week upon all of the fruit-bearing trees and again a record was kept 

 of all the Mediterranean fruit-flies and beneficial insects captured in 

 the traps. A comparison of the number of fruit-flies caught in the 

 kerosene traps before, during and after spraying would test the value 

 of the fruit-fly remedy. 



The following table shows the number of male and female fruit- 

 flies which were captured in the oil traps at intervals of from two to 

 four days for a period of five weeks before spraying: _ 



TABLE I 



Number of Male and Female Mediterranean Fruit-Flies Captured in Ten 

 Kerosen*e Traps at Intervals of Two to Four Days for a Period of Five 



Weeks Before Spraying 



9 



Oct. 8- 9, two days' catch 683 2 



Oct. 10-11, two days' catch 631 0 



Oct. 12-13, two days' catch 454 0 



Oct. 14-16, three days' catch 734 3 



Oct. 17-20, four days' catch ' 1,090 1 



Oct. 21-24, four days' catch 1,150 0 



Oct. 25-28, four days' catch 1,622 6 



Oct. 29-Nov. 1, four days' catch 986 3 



Nov. 2-4, three days' catch 951 2 



Nov. 5-7, three days' catch 491 7 



Nov. 8-11, four days' catch 1,411 12 



Thirty-five days' catch 10,203 36 



36 



10,239 Total 

 f 291 males captured per day. 

 Average ] ^ female captured per day. 



[ 292 Total. 



