REPORT OF CRANBERRY SUBSTATION FOR 1914. Ill 



but does the insect itself no similar harm. A fireworm infestation always 

 becomes noticeably injurious first at some distance from the upland, and 

 bogs of large size and compact form are much more often badly infested 

 than are smaller ones. This is due to the fact that it takes some time for 

 the natural enemies of the pest to work in from the upland and become 

 effectively numerous on all parts of a large bog, especially on the middle 

 part, after the spring flooding is done. In connection with this fireworm 

 situation, the following findings, concerning this year's distribution of 

 fruit worm parasites on the station bog and on a dry l^og near by, are 

 distinctly interesting, the figures given in the table showing the percentage 

 of fruit worm eggs or womis found parasitized in the different locations 

 indicated: — 



Table 6. — • Disfributioii of Effectiveness of Principal Fruit Worm Para- 

 sites. 



' Because of a mathematical error by the writer, the percentages (32 and 30) given in the 

 Report of the 27th Annual Meeting of the Cape Cod Cranberry Growers' Association, 1914, 

 page 21, were inconect. 



It will be seen that the distribution of the Chalcidid and Ichneumonid 

 parasitism was, in a general way, like that found to obtain, as shown in 

 previous reports, with the enemies of the firew^orm. The dry bog used 

 in this comparison is about two acres in area. The center of the station 

 bog is about 250 feet from the upland. The three "edge of station bog" 

 locations were on different sides of the bog. The examinations on which 

 these figures are based were made during the first two weeks in August. 

 Each figure is an average, representing numerous examinations. The 

 station bog was reflowed for the last time a little over seven weeks before 

 these parasite investigations were made. When all these facts are con- 

 sidered, the great influence of flooding on the distribution of the first two 

 of these parasites becomes at once apparent. It will be seen, however, 

 that the water did not seem to affect the Braconid very much, the results 

 of the investigation in this regard being contrary to those of last year's 

 rearing tests. If last year's report is referred to (page 56), however, the 

 foUowing remark concerning the results of those tests wiU be found: 

 "From a study of the life history of Phanerotoma tibialis, it is not easy to 

 see just how the flowage can affect its prevalence to so marked an extent." 

 In the present opinion of the writer it will be found that flooding does 



