208 



Maine Agricultural Experiment Station. 1917. 



From a portion of the infested berries, 12,154 puparia were 

 obtained. The puparia were placed in moist sand in glass jars 

 with cheese cloth covering- the mouth of each container. The 

 jars were transferred from the insectary to a laboratory and 

 were kept out of direct sunlight. On August 9, two female cur- 

 rant fruit flies emerged and by the end of the month 17 trypetids 

 had issued. Of this number 11 specimens were apparently nor- 

 mal but 6 were abnormal due to the fact that the wings did not 

 expand properly. This abnormality may have been caused by 

 the loss of moisture from the sand. A few adults emerged also 

 during September. 



If a second brood of flies issued under natural conditions, 

 one would expect an infestation of such berries as were over- 

 looked by the pickers after the crop was harvested. Accordingly, 

 currants and gooseberries were gathered on August 15, and 

 placed on sand in breeding jars. One month later the sand was 

 sifted but no puparia were found. 



In view of the fact that conditions were not normal under 

 insectary and laboratory conditions, it was decided to determine 

 whether a second brood occurred under field conditions. During 

 the season of 1915, 101 quarts of infested gooseberries were dis- 

 tributed in four large cages (height 35, length 36, width 31 

 inches) with top and sides made of mosquito wire. The vary- 

 ing soil conditions with reference to sunshine and shade under 

 which the cages were placed over the infested gooseberries in 

 the field are indicated in table 15. The cages were visited daily 

 except on heavy rainy days. In none of the cages did a single 

 adult emerge. There is no evidence of a second brood under 

 natural conditions at Orono, Maine. 



TABLE IS. 



Soil Conditions Under Which Cages Were Placed Over Infested 



Gooseberries to Determine Whether a Second 



Brood Occurs. 



Cage Location 



gQij Sunshine or 



Infested 



Dates drops 









shade 



gooseberries 



were gathered 



No. 1 



Adjacent 

 to barn 



Sod removed from 

 rich black soil 



Partial shade 



31 qts. 



June 13—26 



No. 2 



Hay field 



Sod 



Sunshine 



32 qts. 



.June 27— July 3 



No. 3 



Forest 



Plowed clay 



Shade below 

 alder tree 



22 qts. 



July 4—10 



No. 4 



Orchard 



Tufts of grass 



Shade below 



16 qts. 



July 11—17 







growing in clay 



apple tree 







