34 MASS. EXPERIMENT STATION BULLETIN 168. 



winter flowed every year for several years, this flowage having been let 

 off between March 15 and April 1 in both 1914 and 1915, and has been 

 resanded every other year for the past twelve years. It was reflowed in 

 June as usual. Early Black and Late Howe vines were injured somewhat, 

 but the variety most affected was the Chipman. 



A- a matter of passing interest, it was noticed that the caterpillars of 

 the apple sphinx moth {Sphinx gordius Cramer), usually found on the 

 bogs in considerable abundance by the pickers, seemed to be almost 

 entirely absent this fall, not a single one being found on the station bog 

 where they were in evidence in large numbers in the fall of 1914. 



The writer has observed the oyster-shell scale {Lepidosaphes idmi L.) 

 in more or less abundance on cranberry vines on dry bogs for several 

 years, a rather seriously injurious infestation being occasionally found. 

 This insect apparently never becomes very abundant on bogs that are 

 winter flowed. 



The Gypsy Moth {Porthetria dispar L.)- 



There are apparently four distinct ways in which a bog may become 

 infested with this pest, as follows : — 



1. By the Hatching of Eggs deposited on the Bog the Previous Year. — 

 This is probably the principal source of trouble under present conditions. 

 Egg masses on a bog in Carver which, having become completely flowed 

 by the accumulation of rains to a depth of 10 inches by the 1st of February, 

 had the water all pumped off by the 11th of April were observed by the 

 owner to hatch fairly well afterward. 



The writer collected a quantity of egg masses, all from the same general 

 locality, and separated them into three approximately equal batches. 

 One batch was placed in a can in the basement of the station screen-house 

 for the winter as a check. The other two were submerged in 3 feet of 

 water in a pond on January 14. One of these lots was taken out of the 

 pond on April 1 and the other on May 20. Practically all the eggs kept 

 in the screen-house hatched normally, while only about half of those 

 taken from the water on April 1 and none of those taken out on May 20 

 hatched. These experiments indicate that late holding of the winter 

 flowage (until May 20), when practicable, may be relied upon to wipe out 

 an old infestation. 



If, for any reason, late holding of the winter water is not desirable, 

 reflowing will undoubtedly prove a satisfactory method of control where 

 water supplies are abundant, if applied about May 20 and again about 

 June 5, care being taken to kill by burning or by spraying with kerosene 

 those caterpillars that succeed in floating ashore alive. If spraying must 

 be resorted to, it should be done while the worms are j^et in their early 

 stages. Most of the eggs usually hatch between May 5 and May 18. 

 To be most effective, the spraying should probably be done about May 15, 

 and should, if the infestation is very serious, be repeated a week later to 

 kill the worms that hatch afterwards. It is the writer's experience that 



