996 I. M. Hawiey 
Three field cages, containing bean plants sprayed, respectively, with 
powdered arsenate of lead (2 pounds to 50 gallons of water), calcium 
arsenate (1 pound of the powder to 50 gallons of water), and water alone 
to serve as a check, were set up in the laboratory field in July, 1920. 
Twenty slugs were placed in each cage. The plants sprayed with arsenate 
of lead were freely eaten, as had been the case in previous, experiments; 
but those sprayed with calcium arsenate showed little evidence of any 
feeding after the first two days. Several dead slugs were found in the 
calcium-arsenate cage, while none were found in the arsenate-of-lead cage. 
The check plants, sprayed with water only, were almost entirely destroyed. 
The searcity of slugs in the field had made it impossible to test the caleium- 
arsenate spray on a larger scale. 
A cage was placed in the field covering eight bean plants on July 7, 1920. 
Four of these plants were sprayed with bordeaux mixture and four were 
left unsprayed. ‘Twenty slugs were then placed in the cage. A week 
later the unsprayed plants were badly eaten, while the sprayed plants 
were almost untouched. Only where a leaf had been missed by the spray 
was it injured. 
Since the above work was carried on, the excellent paper of Lovett and 
Black (1920) has come from the press. As a result of many careful ex- 
periments, these writers conclude that, for Oregon conditions, a spray of 
bordeaux mixture (4—4—50) as a repellent, supplemented by a poison bait 
of calcium arsenate (one. part by weight to sixteen parts of chopped let- 
tuce), is the most effective means of slug control. When lettuce is not 
available, cabbage, kale, clover, or other succulent leaves may be used. 
The writers say that this bait should be scattered in small heaps at fre- 
quent intervals over the infested area. The importance of cleaning up 
crop remnants and débris about fields and gardens is also emphasized. 
In an experiment testing the efficiency of this combination of repellent 
and poison bait, Lovett and Black found 33 out of 35 slugs dead at the end 
of twenty-four hours. The bordeaux had kept the slugs from the plants 
and they were killed by feeding on the poison bait. 
As previously stated, the severity of the winter of 1917-18 apparently 
killed many hibernating slugs and many slug eggs. Few slugs have been 
found in New York bean fields since that time, and the writer has not 
found conditions favorable for control experiments in the field. In 1920 
there were more slugs in bean fields than in the two preceding years, but 
very little injury resulted. The control work has therefore been limited 
to field-laboratory and greenhouse experiments carried on whenever 
slugs were available. Results of laboratory experiments have at times 
been contradictory, and, since laboratory control measures often prove 
entirely inadequate in field practice, it is impossible at this time to do 
more than suggest possible control measures for field use under such 
conditions as those of western New York. 
