480 Report of the Department of Entomology of the 



may be left in the holes during the drilling process; and (3) by the 

 introduction of spores in the oviposition punctures on account of the 

 remarkable habit of the insect, which employs its excreta to close 

 the openings in the bark after the deposition of the egg. Experi- 

 mental proof of such carriage of the disease is, however, lacking, 

 but studies to this end are being conducted by this Station. 



susceptibility of tree crickets to spraying and other orchard 



practices. 



The occurrence of comparatively small numbers of tree crickets 

 in well-cared-for orchards, except as they adjoin raspberry patches 

 and weedy areas, indicate that the conditions that exist in such 

 plantings are not congenial to these insects. The behavior of the 

 tree crickets in this regard is strongly suggestive of the habits of 

 well-known apple-maggot (Rhagoletis pomonella) in apple plantings 

 in this State. Both insects thrive best in neglected orchards and 

 are for the most part of little importance in plantings that are care- 

 fully managed. It appears that such approved practices as pruning, 

 cultivation and spraying afford protection to the trees from these 

 pests. As with the apple maggot, a satisfactory explanation as to 

 how these operations affect tree crickets is lacking. As yet we have 

 to fall back on suppositions. It does not appear that pruning as 

 ordinarily carried out in commercial orchards would have any 

 appreciable influence on the numbers of the crickets. Clean culture 

 would likely prove unfavorable to them. Following storms and high 

 winds they may sometimes be found on weeds and other under- 

 growth, and the absence of such plants in cultivated orchards might 

 prove detrimental to the insects by rendering them more exposed 

 to the attacks of birds and other foes. Moreover in view of the 

 phytophagous habits of these creatures a hypothesis which seems 

 quite probable is that as a result of applying arsenate of lead to 

 apples, as is now so extensively practised in commercial plantings, 

 the crickets actually feed on sprayed foliage and succumb to this 

 poison. 



In the absence of data bearing on this latter point it seemed 

 desirable to determine the effects of applications of arsenicals at 

 usual strengths to foliage upon these insects, and to this end two tests 

 were conducted by confining different lots of crickets, of five to six 

 individuals, to sprayed and unsprayed foliage of apple trees. In the 



