106 MASS. EXPERIMENT STATION BULLETIN 160. 



following those conditions was a fair one. This year the tips died badly, 

 and the budding for 1915 was poor. 



The tips have been carefully examined every year since this trouble 

 was first noticed, but the cause of the injury was not discovered with 

 certainty until 1914. The tip worm was suspected from the first, but 

 as the maggots of the broods which appear before blooming time were 

 known to always make their cocoons in the tips of the vines, the cocoons 

 remaining as certain evidence of their work even after the flies themselves 

 had emerged and disappeared, it was thought that at least cocoons, if 

 not maggots, ought to be found in connection with the tip injury coming 

 after the bloom, if it was caused by this insect. 



This year a special effort was made to ascertain the cause of the trouble. 

 The tips were examined before they showed injury, while the bog was 

 in full bloom, and maggots in various stages of development were soon 

 found in a good share of them, as many as five sometimes being present 

 in one tip. Tip worm eggs were also found in abundance. In less than 

 three weeks the infested tips had dried up, the maggots having disappeared 

 without leaving cocoons. There was no longer any doubt as to the cause 

 of the injury observed in previous seasons. It was soon found that the 

 maggots of this, the most injurious brood, leave the tips and go down 

 to the sand under the vines to form their cocoons. Unfortunately, it 

 was not discovered in what condition the insect passes the winter. It 

 is suspected that it may remain in the cocoon and be able to endure 

 winter flooding. 



As soon as this insect was found in such abundance on the station bog 

 an examination of other bogs was begun, and a great variation was found 

 among them in the amount of tip worm damage, due, apparently, to 

 the treatment they had received. Two-thirds of the tips on the station 

 bog were injured, and practically all of them were hurt on a bog of 4 or 

 5 acres in Carver. On some bogs, however, the damage was only from 

 3 to 5 per cent. From 50 to 60 bogs were examined in the course of this 

 investigation, and it resulted in the following conclusions: — 



1. That flowed bogs, in case they had not been resanded before the 

 1st of May, were, as a rule, much more seriously injured than were strictly 

 dry bogs (without winter flowage). In its relative abundance on dry 

 and floAved bogs, the tip worm seems to be in a condition similar to that 

 of the flowed-bog fireworm, though the reasons for the condition may 

 not be the same with both species. 



2. That flowed bogs which had been resanded the fall before or in the 

 spring before the 1st of May were, as a rule, much less seriously injured 

 than those not thus resanded. In nearlj^ every case those most hurt 

 had not been resanded for two years or more. 



3. The "Late Howe" variety, as a rule, showed distinctly more injury 

 than did the "Early Black." 



4. No bog showed great tip worm injury where traces of severe frost 

 damage were in evidence. 



