THE ARMY WORM 1N CRANBERRY BOGS, 13 
DEPARTMENT OF AGRICULTURE, 
ENTOMOLOGICAL Diviston, 
July 7, 1882. 
Mr. Cuas. G. Rockwoop, Newark, N.J.: 
DEAR SiR: In regard to the saw-fly you sent me as injurious to cranberries, I will 
say that in my breeding jars they refuse to eat the cranberry plants. It now occurs 
to me that you may have possibly overlooked the real authors of the mischief, and 
that the saw-fly larvee have merely fallen upon the cranberry plants from some other 
plant. I beg you now to ascertain whether the larve really feed on the cranberries. 
By doing so you will greatly oblige. 
Yours, truly, ; 
C. V. RILEY, 
Entomologist. 
NEwaARkK, N. J., July 10. 
C. V. Ritey, Esq., Entomologist : 
DEAR Sir: Your favor of the 7th instant has been received. There is no doubt that 
the worm of which I sent you the young did the mischief by eating the vines. I sup- 
pose that my farmer happened to put in the box only old cranberry vines. They do 
_not touch the old vines, but eat the young shoots off this year’s tender growth, and 
only after exhausting the supply of grass which grows among the vines. But eating 
- the new growth takes the fruit buds and destroys this year’s crop, and takes also the 
growth which is to bear next year. The worms undoubtedly feed upon the vines. They 
leave upon the ground many leaves, but must consume largely. 
When I was there, in spots not reached by the worms the new growth arose solid 
above the old vines, say, 4 inches, so that nothing else could be seen. On the other 
side of the ditch would be a patch eaten clean down to the old vines, leaving them as 
they were when the water was taken off and before new growth has started, and the 
whole patch 4 or 5 inches lower in solid growth than the untouched patch adjoining, 
and of difterent color. 
Respectfully, 
CHAS. G. ROCKWOOD. 
We visited Mr. Rockwood, at Newark, N. J., shortly after the receipt 
of his last letter, and concluded from further information obtained that 
the saw-fly larve were certainly not the authors of the mischief, but: 
that the Army Worm in all probability did the damage. Yet, as doubt 
remained, we were anxious to settle the question, and sent Mr. E. A. 
Schwarz to make examination on the spot. The following is the report 
of his observations : 
Sir: In accordance with your directions I have made a study of the injury done to 
Mr. Rockwood’s cranberries as far as it was possible at the time, the insect that did 
the damage having disappeared more than six weeks previous to my visit at Ham- 
monton. ; 
The Rockwood cranberry farm is divided into squares, each of about 50 acres, sur- 
rounded by high dikes, and intersected by numerous irrigation ditches. Two or three 
other squares are just being constructed, but are not yet inclosed with dikes. The 
cranberries being fully formed at the time of my visit, August 1, there was no difh- 
culty in taking in at a glance from the high dikes the extent of the damage done by 
the insect. It was apparent that the damage was confined to a number of the smaller 
squares formed by the irrigation ditches. On some of these hardly any berries were 
to be seen, while other squares adjoining the damaged ones, and only separated from 
these by the narrow ditch, were not injured at all. On the newly-constructed squares, 
where there is an abundance of grass, the newly-planted vines had severely suftered. 
