The Codling-Moth. 141 



later. Our observations on the development of the young fruit, as 

 just described, led us to theorize that the poison must have lodged in 

 the open calyx cup (see figure 145) and, no rain intervening to wash 

 it out, remained there while Nature proceeded to draw a protecting 

 roof over it (see figure 146) and finally left it securely hidden in the 

 calyx cavity. Here it was found by a young apple-worm a week or 

 so later. 



We soon found, as have other observers, that from 75 to 85 per cent, 

 of the worms which hatch in the spring enter the apples through the 

 blossom-end; and we found, also, that these young worms got their first 

 and several subsequent meals in this calyx cavity. It then only remained 

 to prove the possibility of there being poison therein which had been left 

 there when the trees were sprayed two weeks before. Fortunately, about 

 the time the worms were hatching, we found some apples which had been 

 sprayed with Paris green and Bordeaux mixture just after the blossoms fell. 

 A careful examination of the calyx cavity with a lens revealed particles of 

 a bluish color. Were these particles of Bordeaux mixtures with their 

 attendant bits of poison ? Only the chemist could tell this. We at once 

 carefully removed the calyx lobes. and surrounding skin from about 50 of 

 these apples, and then submitted only that portion of the apples contain- 

 ing the calyx cup to our chemist, Mr. Cavanaugh. He soon reported 

 traces of arsenic. The quantity found was scarcely enough to weigh, and 

 it seemed as though it were not enough to kill the little apple-worms. 

 But when one remembers that only four or five gallons of the spray are 

 usually applied to a whole tree, and when this is divided up among the 

 millions of leaves and the thousands of apples on that tree, it is easy to see 

 that the amount of arsenic which a single fruit would get, or even 50 of 

 them, would be exceedingly small. Would it be enough to kill the young 

 apple-worms ? Careful experiments have shown that it takes much less 

 poison to kill caterpillars when they are small ; and as the young apple- 

 worms are scarcely a sixteenth of an inch in length when they begin 

 feeding in the calyx cavity, it would take only an infinitesimally small 

 amount of arsenic to kill them.* 



* Munson has figured out how much poison would be hable to stay on one 

 apple, allowing two sprayings of two gallons each to a tree. His figures 

 show that the amount of poison per fruit would be less then 3-1000 of a grain. 



Others have made chemical analyses of the blossom-ends of apples, and 

 report no traces of arsenic, but their material was not taken until several 

 weeks after the spraying was done (and it may not have been done when the 

 calyx cup was open), hence could be of little value to determine the point 

 in question. 



