April, '15] 



GLENN: APPLE FLEA- WEEVIL 



283 



would be trapped in this way. Five days later an average of 423 

 beetles was found on these bands. Two such bands were placed on 

 the trunks of several trees, and in three days an average of 656 beetles 

 to the tree had been -caught. The following spring 64 trees in this 

 same orchard were banded early before the beetles, had emerged from 

 their winter quarters, in the hope that they might be caught in large 

 numbers while ascending the trees. The first beetles to emerge in 

 spring were rather sluggish and attempted to reach the branches of 

 the tree by crawling up the trunk, but later when the weather became 

 warmer, many of them flew directly from the ground to the branches, 

 with the result that while the beetles which attempted to crawl up 

 the trunk of the trees were prevented from doing so, and many of them 

 were caught in the bands, others succeeded in getting past the bands 

 by flying. Many beetles crawling up the trunks of the trees were ob- 

 served to take wing and again alight on the trunk, and others flying 

 from the ground were also observed to alight on the trunk. Some of 

 these alighted on the bands and were unable to extricate themselves; 

 a large proportion of the beetles which were caught in the bands were 

 caught in this way, and for this reason the wider the bands were the 

 greater was the number of beetles caught. It was estimated that bands 

 from three to five inches wide placed about the trunks of trees re- 

 duced the number of larval mines in the leaves of the banded trees 

 about 50 per cent. Wider bands would be more effective but also more 

 expensive, and it is doubtful if it pays to go to the trouble and expense 

 of using a protective measure whose efficiency is only 50 per cent. 



Arsenical Sprays. — Since the larvae of this species are leaf-miners, 

 there is no way of reaching them with arsenical sprays; but the adults 

 feed upon the tissues of the under side of the leaves and hence arsenical 

 sprays applied so as to cover the under sides of the leaves should 

 theoretically be effective. Sprayed orchards, however, have suffered 

 almost as badly as unsprayed ones. This fact may possibly be ex- 

 plained in several ways: viz., the beetles may be less susceptible to 

 poison sprays than other insects that are easily controlled by them; 

 the beetles may possibly be able to discriminate between poisoned 

 leaves and those not poisoned, and in this way avoid the poison; 

 the spray may not have been applied so as to cover thoroughly enough 

 the under sides of the leaves where the beetles feed; and lastly, the 

 sprays may not have been applied at the proper time. 



By inclosing beetles in a cage with poisoned leaves it was found that 

 when they fed freely some died within a day or two while others lived 

 for a week or more, indicating that while they are not immune from 

 poisons, some are much less susceptible to poison than others, or else 

 feed less freely upon poisoned tissues. 



