524 



l)urrows of the individual larvae are not separated ; in a small branch 

 there is one long, continuous burrow with rather large openings at 

 intervals, with as many or more larvae in the tunnel as there are 

 openings. At what stage in development these openings are made is 

 not known. The larvae are not able to subsist on dead wood ; all 

 those observed in the field were feeding upon living branches and 

 attempts to breed them in quince branches cut from the trees were 

 unsuccessful. The larvae begin to make their cocoons about the last 

 week of March in their second year, all having pupated by the end of 

 July. The pupal stage lasts about five months. A calendar is given 

 tabulating the life-cycle of this borer, which occupies a total of 760 

 days. Stages of two successive generations may be found in the same 

 orchard. 



Remedial measures included experiments in inserting a wire into the 

 burrows, but the results show that only about 80% of the insects can 

 be killed by this method, which is often difficult to carry out and is 

 slow in application. To be effective, it should be done during 

 September, when the openings of the burrows are large enough for 

 wire to be inserted and when the moths of the older generation have 

 not yet emerged. The wire should be inserted up, as well as down, 

 the burrow. The cutting away of the area of bark under which the 

 larvae are feeding before they enter the wood and scatter has been 

 found impracticable for several reasons : it would not touch the 

 larvae that enter the wood almost immediately upon hatching ; some 

 young infestations cannot be reached owing to their position ; and this 

 method, even if successful, would have to be applied over at least two 

 years, as there is no period when all individuals are to be found just 

 beneath the bark. 



The injection of different insecticides into the burrows has been 

 tried with varying results, which are shown in a table. Paraffin and 

 raw linseed oil are effective in killing active larvae, but fail to destroy 

 the larval and pupal stages within the cocoons ; arsenate of lead and 

 soap and water and tobacco-soap solution are useless for this purpose. 

 Paraffin oil should not be 'used on account of its injurious effect on 

 the bark of the tree. One application of raw linseed oil, injected into 

 the burrows of both old and young larvae, wall kill over 90 per cent, 

 of the insects, if applied about the middle of March, when all the eggs 

 have hatched, when all the insects are in the active larval stage, and 

 when the burrows of the young larvae are sufficiently large to facilitate 

 the insertion of the syringe. The sawdust-like accumulations should 

 first be brushed away with the hand from the openings, then the 

 injections should be made with a small syringe of 1 or | pint capacity, 

 beginning at the topmost hole. It is not necessary to insert the 

 syringe in every hole. Two or three weeks after this treatment the 

 trees should be inspected and, if any burrows show fresh accumulations 

 of sawdust at their openings, these should be treated again. Attempts 

 were made to prevent emergence of over 100 moths by plugging the 

 openings of the burrows with soap, but this was a slow process and 

 over 50 per cent, of the moths succeeded in emerging by pushing out 

 the obstruction. All old and neglected quince hedges or bushes should 

 be destroyed to prevent the spread of infestation to properly cultivated 

 orchards. 



