DISPOSAL BY BURIAL OF FRUIT-FLY INFESTED FRUIT 



11 



the mangoes were well spaced and that those in the outer rows actually 

 touched the sides of the pits. The first mangoes were buried March 7, 

 1932. The next operation was to fill the pit with either dry or moist 

 sand until the 20-inch level on the stake was reached. The entire 

 surface of the sand was then well packed. After this packing, more 

 sand was added until the 20-inch level was again reached. _ Packing 

 with the tamper was then repeated. After the second packing, sand 

 was added up to the 20-inch level on the stake, but was not packed 

 again. The effect of this packing is shown in table 8. 



Table 8. — Depression of the sand of the burial pits caused by packing with a wooden 



tamper 



Dry series 



Moist series 



Pit no. 



First 

 pack- 

 ing 



Second 

 pack- 

 ing 



Total 



Pit no. 



First 

 pack- 

 ing 



Second 

 pack- 

 ing 



Total 



2 



Inches 



27/l 6 



2Me 



334 



2 



Inches 

 VA 

 l 



m 



i 



Inches 



311/16 

 3?/16 



4% 

 3 



1 



Inches 

 4H 



53/l 6 



6 



Inches 



25/16 



2 



2/2 

 2% 



Inches 



6H/6 



4 



3 



6i/6 



6 



5 ..... 



7% 



8 



7 



8J4 







Soil temperatures were recorded among the mangoes at the 20-inch 

 level of pit no. 6 from March 29 to May 15, 1932, inclusive. During 

 this time the temperature was very constant, ranging between 28° 

 and 31° C. (82.4° and 87.8° F.). The daily mean air temperatures 

 taken in the shade for this period (except Apr. 11, 12, and 13) ranged 

 from 20.5° to 29° C. (68.9° to 84.2° F.), 6 the mean for the 45 days being 

 25.8° C. (78.4° F.). 



The examination of the surface of the pits was greatly facilitated 

 by the sand and the white sides of the cages placed above the pits. 

 No adults emerged from any of the pits. When all chance of adults 

 emerging had passed, the dry-packed sand was removed in 1-inch 

 layers and sifted through an 18-mesh sieve. Nearly all the sand 

 passed through the sieve, leaving mostly insect material which could 

 be removed and examined very easily. The sand that had been 

 moistened became very hard upon packing and standing. It could 

 be removed only in large pieces which could be broken with difficulty. 

 For this reason the sand in only one of the pits of this series was 

 removed and examined. The small amount of insect material 

 recovered indicates that probably much of it was destroyed and lost 

 when tne chunks of sand were broken. It is inconceivable that the 

 flies could move any distance through sand so compact and solid. 



A summary of the material obtained by sifting the sand is shown in 

 table 9. A total of 596 flies, or 46.4 percent of those that emerged, if 

 based on the total of 1,284 empty puparia, were recovered from the 

 four pits that contained dry sand. Only 6 flies, or 3.6 percent, out of 

 a possible 163 flies, were recovered from the single pit examined of 

 those containing moist sand. Only 1 fly was found as high as 9 inches 

 above the fruit, but 1 dead larva was found 1 1 inches above the fruit 

 in one of the pits. It will be noted that the great majority of the flies 

 were found within the 4 inches of sand above the fruit as well as the 



6 Summarized from 2-hour readings taken from the thermograph. 



