APPENDIX. 309 



periments by Lodeman. Craig', and others have demonstrated that the poison 

 is just as etfective affainst the codling moth when used in combination 

 with the fungicide as when used alone. When used alone there should be 

 added to the paris green, but more especially to london purple, about twice 

 as much freshly-slaked lime, to prevent any caustic action on the foliage 

 resulting from the presence of soluble arsenic in the poisons : the lime 

 already in the bordeaux^mixture does this. It is therefore now a common 

 practice among fruitgrow'ers to use the poison ( for the codling moth ) in 

 combination with the bordeaux mixture ( for the api)le scab fungus ). thus 

 "'killing two birds with one stone." In mixing paris green or london 

 purple it is always best to first wet it up in a small quantity of water, making 

 a sort of thin paste : if the dry i)oison is thrown directly into a large quan- 

 tity of water it can not be mixed so quickly nor as satisfactorily. 



When to sprfiy for the codling moth — The commonly accepted notion that 

 the eggs of the insect were laid in or on the calyx of the fruit soon after the 

 blossom fell, and the fact that a large ])ercentage of the worms enter at this 

 point, led to the recommendation to s])ray just after the blossoms fell. The 

 experience of those who have sprayed has confirmed this conclusion, and it 

 is now the universal practice to try and make the first application at this 

 time. As Mr. Lodeman has put it : "The falling of the apple blossoms is 

 the signal for the use of arsenites in the destruction of the codling moth." 

 Our observations would indicate that a safe rule will be to spray the fruit at 

 any time within a week after the Vjlossoms fall : if it rains within a few 

 days repeat the spray at once. The reason why and the great importance of 

 spraying at this time is discussed under the next heading. Where there are 

 both early and late varieties in an orchard it may be necessary to spray 

 some trees before others: but usually there is not enough difference in 

 time between the dropping of the blossoms from late and early varieties so 

 but what all trees can be sprayed the same day. Although experimenters 

 demonstrated that it was necessary to spray at this time to secure the best 

 results, yet but few really understood the "why" of it: that is, just how it 

 did or could affect the insect w^hen applied at this time. 



Hoio the poison affects the codling moth — Those who critically examine the 

 literature, will be surprised to find how few definite statements there are 

 regarding this very important phase of the question of combating this insect. 

 It seems to have been the current notion for some time that the poison spray 

 not only killed some of the insects, but that it also acted as a preventive in 

 some way. It w^as in consequence of the repeated requests of Mr. Lodeman 

 for information on this point that we began studying this old enemy, about 

 which most of us have thought there was nothing new to be learned. We 

 were surprised to find several times that our observations would not agree 

 with the stereotyped notions regarding the life and habits of the insect at 

 the time when fruitgrowers were spraying to kill it. Our first surprise was 

 to find that the moths did not begin to emerge in consideraj3le numbers until 

 several days after the blossoms had fallen, and consequently we were unable 

 to find any eggs until the blossoms had been off' for a week or more. 



Meanwhile, we had been watching the development of the young fruit, 

 and had seen something of great im])ortance to friutgrowers, and which 



