DISPOSAL BY BURIAL OF FRUIT-FLY INFESTED FRUIT 6 



twice as deep as others. Soil was added to fill the depression caused 

 by the packing. It was packed a second time and leveled by adding 

 more soil. The soil in the pits of the other series was left untouched. 



Bottomless wooden cages 8 inches high covered with 18-mesh screen 

 wire were used to cover the pits. The cages extended several inches 

 beyond the edges of the pits. The larger size of the cages greatly 

 reduced the amount of shade that fell on the surface of the soil. 



The surface of the pits was examined daily during the period when 

 there was a possibility of adult emergence. The coarse surface made 

 the examinations for adults difficult because they would either die 

 and fall between the particles or perhaps hide between them in an 

 attempt to find protection from the sun. No live adults were found 

 in any of the cages above the pits during the experiment. MePhail 

 and Bliss, 4 who carried on somewhat similar experiments with this 

 insect, observed that "Some flies emerged even at the greatest depth 

 of 18 inches, but all of these were so badly crippled that they died 

 soon afterwards; . . ." Although all of the adults that emerged 

 in the experiments were found dead, they appeared to be normal. 

 The fact that they lived only a short time is attributed to exposure to 

 the sun without food and water. 



Darby and Kapp 5 obtained the complete mortality of 50 adults of 

 Ajiastrepha ludens at a cabinet temperature of 43.1° C. (109.5° F.) in 

 less than 2 hours. Since temperatures as high as 52° C. (125.6° F.) 

 were recorded at the surface of the pits as early as 11:30 a. m., it can 

 readily be seen that adults would live only a very short time when 

 unable to escape from such conditions. 



After there was no possibility of further emergence of fruit flies 

 from pup aria, the soil of all the pits, with the exception of the 40-inch 

 pit in the unpacked series and the 33- and 40-inch pits in the packed 

 series, was carefully examined for adults, puparia, and parasites. The 

 procedure was the progressive removal of 1-inch layers of soil from each 

 of the pits until all had been removed. This soil was sifted through 

 an 18-mesh screen sieve. Since only about 35 percent of the soil 

 passed through such a sieve, the remainder had to be examined care- 

 fully to find the insect material. Probably many specimens were 

 broken and lost by this method. Most of the soil in the unpacked 

 series of pits had been sifted in this manner when the rainy season 

 began, which precluded the further use of this method. The soil of 

 the other pits was then examined by taking each 1-inch layer of soil 

 and washing it through an 18-mesh sieve by means of a garden hose. 

 Most of the soil passed through the sieve when this procedure was 

 followed, leaving only coarse gravel in the sieve. This was dried and 

 the insect material separated from it. In the unpacked series, the 

 pits 18, 22, 23, and 26 inches deep, respectively, were sifted; also the 

 first 14 inches of soil in the pit 27 inches in depth. The soil of the 

 pits 19 and 22 inches in depth of the packed series was also sifted. 

 The soil of all the other pits was washed. 



In the examination of the soil it was found that the puparia were 

 much easier to detect than the dried bodies of the adults. The latter 

 were more easily destroyed in the sifting operations, and this partially 

 accounts for the far greater number of puparia recovered. Only 



* McPhail, M., and Bliss, C. I. See footnote 2. 



8 Darby, H. H., and Kapp, E. M. observations on the thermal death points of anastrepha 

 LUDENS (loew). U. S. Dept. Agr. Tech. Bull. 400, 19 pp., illus. 1933. 



