46 MAINi; AGRICULTURAL LXPJiRlMENT STATION. I9I3. 



following experiments were made during the summer of IQ12, 

 at Orono. 



A small field was planted with potatoes and divided into five 

 plots ; one of wdiich was spra3^ed with Bordeaux to which was 

 added three pounds of arsenate of lead, per 50 gallons of spray 

 mixture; the second like the first hut with the addition of 2 T-2 

 quarts of Karo corn s3'Tup per 50 gallons of the spray, the third 

 without bordeaux but using three pounds of arsenate of lead 

 in 50 gallons of water; the fourth as in tlie third with the addi- 

 tion of 2 1-2 quarts of syrup; the fifth, unsprayed. The pota- 

 toes were sprayed at intervals of about two weeks during the 

 season, and put on at the rate of 250 gallons per acre. The 

 conditions under which these experiments were conducted ren- 

 dered it impossible for us to keep a quantitative record of flea- 

 beetle injury (counts of flea-beetle punctures) but in general it 

 may be said that there was decidedly more flea-beetle injury in 

 in the unsprayed plot than in the sprayed and least injury in the 

 first and second plots which were sprayed with a mixture con- 

 taining bordeaux. There was no noticeable difiference between 

 the plots wdiich were sprayed with the mixture containing the 

 syrup and the corresponding one without it. Had a pure corn 

 syrup been used instead of Karo corn the result might have been 

 difl^erent. The difiference between the sprayed and the un- 

 sprayed plots was much more noticeable during September than 

 earlier in the season. 



Some laboratory experniients were also made. A number of 

 beetles were placed in a glass jar with some tender potato leaves 

 thoroughly drenched in an arsenate of lead spray mixture 

 (three pounds in 50 gallons.) 



In a second jar Watson's soluble arsenoid (an efficient poison 

 for potato beetles) w^as used; in the third as in the first but 

 with the addition of Karo corn syrup (2 1-2 quarts per 50 

 gallons). At the end of 24 hours all the beetles were still alive 

 in the first and second jars, but over 2-3 were dead in the third. 

 All the leaves showed feeding puncture at the conclusion of the 

 test. Though we are scarcely justified from so limited a series 

 of experiments in assuming that the syrup would be service- 

 able when used on a large scale, nevertheless, the results are 

 interestino: and sus'srestive. 



