1919 EXTOMOLOGICAL SOCIETY. 95 



The damage done by the slug varies with the various plants on which it 

 feeds, according to their age and consistency. Amongst the vegetables above 

 mentioned, it is obvious that the youngest are the most badly infested. 



Thus, beans had only grown three or four leaves when slugs started eating 

 them up; after 8 or 10 days a dried stem was all that was left. It resulted 

 that 50 per cent, of the plants did not bear any crop and 25 per cent, of the 

 remainder only yielded one-third or one-half of the normal crop; one-fourth only 

 was left intact or at least strong enougli to bloom normally and yield accordingly. 

 In a field where there were several varieties, the Burpee beans were completely 

 cut down. 



The crop of peas has only suffered a small diminution. When slugs launched 

 an attack upon their stems, they were already nearing ripeness and had attained 

 a remarkable degree of resistance. There has been a loss of a few leaves and 

 pods, or a total loss of about 2 per cent. 



Of the crucifers, cauliflowers are the only ones that seem to have been 

 injured, and then only when the slugs were successful in penetrating into the 

 fruit. Finally, in the case of pumpkins, there still remained the expedient of 

 removing the injured part, the sides of the hole bored by the slug. 



Control. — The following substances were used : Paris green, arsenate of lead, 

 Bordeaux mixture, quicklime (powder). 



The first two insecticides only gave poor results; they did not seem to 

 diminish the number of slugs in an appreciable degree. 



Bordeaux mixture containing 6 lbs. of lime to -i lbs. of bluestone makes 

 slugs uneasy, kills a few of them slowly, but does not constitute an efficient 

 means of destruction. 



Quicklime has done wonderfully well. It has been dusted on the infested 

 plants, in the following way : 



1. At night, before slugs appear; in order that the success be complete, 

 it is important that all issues leading to the plant be closed to the slug, which 

 is not. always an easy task. 



2. At night, when the slugs are feeding upon the foliage. In this way the 

 best results are achieved. If we can apply lime to come into close contact with 

 the skin of the slug, the latter will die rapidly. The following morning, their 

 inert bodies, reduced by one-half, of a dark green color, are still sticking to the 

 leaves. 



3. Applied during the day, lime loses its efficiency, because the coolness 

 of the night lessens its strength. 



As a rule, dusted lime retains its destructive power, in whole or in part, 

 as long as it does not rain ; it is excellent in a fresh condition. A small particle 

 of lime is then sufficient to kill a slug. We have watched the doings of 12 slugs 

 placed on a board and surrounded by a wall of lime, one-quarter of an inch in 

 height. Not a single one was successful in getting over the obstacle : as soon 

 as they came into contact with lime, they twisted convulsively and died in the 

 space of 2 to 60' minutes, according as the injured part was more or less great 

 or sensible. Secretions very abundant at first, soon l)ecome nil, coinciding with 

 the complete absence of movement. 



It would be very difficult to find a more energetic remedy and of easier 

 application. By repeating the dusting of lime, particularly at night, these des- 

 trovers will soon be controlled. 



