REPORT OF CRANBERRY SUBSTATION FOR 1916. 231 



ture. The cocoons in both the incubator and the barrel were taken from 

 the water at 9 p.m., January 15, and were examined the next day in a warm 

 room. All but 9 of the 30 worms that had been in the incubator were dead, 

 whereas all but 3 of the 30 from the pail were alive. Those taken from the 

 pail were as a rule very lively after they got warmed up, most of them 

 crawling actively. On the other hand, none of those from the incubator 

 became active, the live ones showing they were so only when prodded con- 

 siderably, their movements even then being very sluggish. None of the 

 dead worms had begun to decompose. The temperature of the incubator 

 was shown by the thermometers to have ranged from 52° to 66° F. during 

 the test. The temperature of the water in the cans kept in it was 57° F. 

 at the end of the test, and had probably averaged a little under 60°. The 

 temperature in the barrel had ranged from 31° to 39^° F., that of the 

 water in the pail being 35° at the end of the test. 



This incubator and pail experiment was duplicated by a test carried out 

 similarly in all details, except that vaseline bottles of 3^-ounce capacity, 

 with tightly inserted cork stoppers, were used instead of the cans, the 

 cocoons being submerged at noon, Jan. 29, 1917, and being taken from 

 the water at 3 p.m., February 13. Of the 30 worms kept in the incubator 

 16 were dead and 14 aHve at the end of the test, while of the 30 tested in 

 the pail 27 were alive and only 3 dead. Moreover, the live worms fromi 

 the bottles in the pail were much more active after they got warmed up> 

 than were those from the incubator. None of the dead worms had begun 

 to decompose noticeably. In this test the temperature in the barrel ranged! 

 from 32° to 36° F. The incubator got out of order twice, — on the seventhi 

 and tenth days of the test, — its temperature the first time falling to 40° 

 and the second to 33° F. With these exceptions it ran between 52° and. 

 62°, and probably averaged about 56°. 



Many of the cocoons used in these tests were carefully opened under- 

 water at the end of the submergence, and, while they were all found to be 

 largely filled with water, none were without a little air or gas, this indi- 

 cating that the findings in this regard previously reported by the writer ^ 

 were not quite accurate, the former examinations apparently not having 

 been sufficiently careful. 



The results of these experiments seem to prove that the effect of sub- 

 mergence of the worms in their cocoons depends largely, if not principally, 

 upon the temperature of the water, and they suggest that a flowage after 

 picking, if it is begun before October 1 and continued for twelve or possibly 

 even ten days, may control this insect as well as late holding of the winter- 

 flowage usually does. It may be said that such a flooding would interfere 

 with harvesting, but as late picking is usually a result of late holding of the 

 previous winter-flowage, and as late holding is most commonly practiced 

 as a treatment for the fruit worm, this objection does not seem valid. 

 Flooding practiced annually after picking would probably have a much 

 less harmful effect on a bog than late holding of the winter-flowage every 

 year has. 



» Bui. No. 160, Mass. Agr. Expt. Sta., 1915, p. 113. 



