142 . JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 15 



loss as a result of mixing the combs from diseased with those from 

 healthy colonies. The first, through systematic selection seems to have 

 successfully isolated the infected combs from the others in two years, 

 but the second let his yard go down to less than 300 colonies before he 

 finally gave up, and melted 100,000 combs. 



Effect of Weather Conditions 



As outside influences which may affect progress, the most important 

 have been the effect of weather conditions on the honey flow. It 

 is of course out of the question to allow the average beekeeper to apply 

 treatment when no nectar is coming in. The summer of 1918, for 

 example, was entirely without honey over a large section of the state. 

 No pressure was placed on the beekeepers to destroy their infected 

 colonies, they dared not treat, and as a result slightly more American 

 foulbrood was found in 1919 in the areas begun the previous season 

 than had been reported at the first inspection. 



Rate of Progress 



Progress in area clean-up work seems to follow a definite course 

 when allowance is made for various outside influences. For example, 

 in Jefferson and Milwaukee counties together, a total of 503 apiaries 

 have been inspected, of which 323 have never been found with American 

 foulbrood. Of the remaining ISO, nearly one-half (86) showed disease 

 in 1918 or 1919 but have been clean since. Of the other half, 44 were 

 still infected in 1920 but were clean in 1921. Of those showing disease 

 this season (50), 17 were either new yards which had been missed be- 

 fore, were outside the area covered in previous years, or had been free 

 from disease at a previous inspection. 



Beginning with 1919 the result has been a fairly tmiform reduction 

 of about 50% a >ear, in all heavily infected areas. Theoretically such 

 a ratio would bring us to a single mfected yard in each of these countie 

 by 1923 or 1924, but it is hard to anticipate the results of the more 

 drastic attack made on the few remaining diseased yards when the total 

 number becomes reduced to a small percent. 



The rate of reduction just given applies to all counties except Dane, 

 in which many large infected apiaries are selling quantities of infected 

 honey in their own locality. Here the amount of reinfection is dis- 

 couragingly high, being related apparently both to honey sales and to 

 the more pronounced economical tendencies of the beekeepers in this 

 area. In Dane county the shaking treatment is used uniformly, and the 

 same state of mind which keeps most of the beekeepers from destroying 



