Ethel M. Doidge 



51 



visits of bees and other insects which have been shown both in this 

 case and in the case of other diseases of a similar nature to be the 

 principal carriers of infection. 



Comfarative Schedule. 



During September, 10 IG, I was able to visit the pear-growing 

 district, and to study the disease in the orchard ; it was too early for 

 the late-fiowering varieties, some of which are the most susceptible, 

 but considerable infection was found in the Keiffers and other varieties 

 which were then in flower. Information as to the susceptibility of the 

 different varieties was also gleaned from various growers, all of whom 

 mentioned the same varieties as the most liable to the disease. 



Pear trees flowering in the Wellington District and in the Pretoria 

 District show no signs of the blackening: a trouble of a somewhat 

 similar nature has been reported, from Potchefstroom, but it has not 



4—2 



