Plant Diseases and Insects. 



by combining the entire count of all varieties, we have for 

 sprayed trees a final of 32.48 per cent, punctured or stung, 

 and 5.71 per cent, containing' larvae, against a final of 41.86 

 per cent, stung and 10.39 per cent, containing larvae for the 

 check trees." 



The history of spraying for curculio proves that the insect 

 can be kept in check by this means, although the advantages 

 derived from the poison are less marked than in the case of 

 the codlin moth. The codlin moth deposits its egg in the cup 

 or blossom end of the fruit, while the little apple is yet erect. 

 In this cup the poison is caught. The curculio, on the other 

 hand, punctures the side of a fruit, and most of the fruits 

 upon which it works are smooth, and the poison does not 

 adhere well. Riley and Howard state these facts as follows : 



" On the whole the remedy is one which is a desirable addition to our list, 

 although it will never become so great a success as the application of these 

 poisons for the codling moth, and for two reasons : (1) The egg is de- 

 posited and the beetle gnaws preferably upon the smooth cheek of the fruit, 

 where the poison does not so readily adhere, and from which it is more 

 easily washed off. (2) The larva, eating directly from the flap, does not 

 come in contact with the poison as does the larva of the codlin moth." 



But the insect gets the poison from the leaves as well as 

 from the fruit. Until recently it has been supposed that the 

 adult curculio, like many other insects, does not eat, and one 

 of our best entomologists stated in 1886 that " Paris green, 

 kerosene emulsion, and other poisons are of no avail against 

 the curculio. He will not eat them." The persistence of cer- 

 tain fruit growers, however, that spraying is effective against 

 the curculio has led to many investigations of the feeding 

 habits of the adult insect. Forbes' experiments* are particu- 

 larly good. Curculios in confinement ate leaves, flowers and 

 fruits of the plum, leaves of peach, and flowers of rose, honey- 

 suckle and snowball. In view of the fact the insects feed 

 thus indiscriminately, Forbes concludes that it may be " worth 

 while to make the attempt to attract the adult to flowering 

 plants in the orchard, other than the peach, with the hope of 

 poisoning it there (especially late in the season) without using 

 these dangerous insecticides on fruits afterwards to be eaten." 

 Of insects in confinement, fed upon poisoned foliage, some 

 died the second or third day, and others soon followed. The 



*I 1 1 sect Life, ii. 3 (1889). 



* 



