Table 1.--Results of laboratory tests with hardened bait consisting of 
13 grams Bayer L 13/59 in 1 pint of dark Karo syrup, June, 1953. In each test 
2,000 house flies were released in a 20- by 18- by 9$-foot room in which 
20 milliliters of the bait had been placed in 10 small bait containers grouped 
within an area of 3 square feet. 
Per Cent of Fly Population Number of Hours Required 
Test No. (2,000 Flies) Killed in 1 Hour for 100 Per Cent Kill 
1 92 12 
a 90 20 
3 94 8 
Table 2.--Results of treatment with hardened bait, consisting of 15 grams 
Bayer L 13/59 in 1 pint Karo syrup, used against the house fly on Illinois prem- 
ises, summer, 1953. 
Square Feet Per Cent Control Miéilliliters Period 
Premises of Obtained With of of 
Floor Space One Application* Bait Used Observation 
Calf barn 1,000 94.0 260 21 weeks 
Fly Lab. office 500 Shai, 50 26 weeks 
Dairy and feeder barn, 5,000 72.0-87.0 1,400 3 weeks 
no Sanitation, windows 
and doors open, no 
screening 
Sheep barn 4,000 G25 450 15 weeks 
Dairy store 800 Gao 3) 8 weeks 
U. of I. office 270 95.0 15 12 weeks 
Grade A dairy barn 1 2,400 90.0 450 16 weeks 
Grade A dairy barn 2 3,000 93,0 450 16 weeks 
Grade A dairy barn 3 L750 92.0 450 16 weeks 
Grade A dairy barn 4 2,400 94.0 450 16 weeks 
Grade A dairy barn 5 2,500** 9520 450 16 weeks 
Grade A dairy barn 6 2, 000** 94.0 450 16 weeks 
Grade A dairy barn 7 2,500** 95.0 450 16 weeks 
Grade A dairy barn 8 4,000 92.0 450 20 weeks 
Dairy round barn, open 4,400 60.0-75.0 1,350 2 weeks 
on all sides, very poor 
sanitation 
Experimental animal meee, 99.0 100 12 days 
rooms, Animal Science (2,000 95.0 150 12 days 
Building 
* ‘The per cent of control was derived by comparing the average fly population 
observed before treatment with the population observed at intervals after treat- 
ment. The apparent lack of control in two cases (less than 90 per cent) was not 
the fault of the technique but the result of lack of both sanitation and screening. 
** Approximate. 
