304 PLANT DISEASES 



begin to open ; second, when the petals of the flowers are 

 falling; and third, when the fruit is the size of peas or 

 slightly larger. If the season be rainy a fourth treatment 

 should be given twelve days after the third. Four ounces 

 of Paris green added to each fifty gallons of the mixture at 

 the time of the third spraying will hold the codlin moth in 

 check. The Paris green should first be made into a thin 

 paste by adding a little water. This paste readily unites 

 with the mixture, and does not seem to decrease its value 

 in any way.' 



Experience has shown that ordinary Bordeaux mixture 

 is apt to scorch the foliage, especially when young, hen^e 

 it is advisable to use the dilute form. 



In cases where the disease has existed previously, the 

 trees should be thoroughly drenched with a solution of 

 sulphate of iron during the winter, commencing with the 

 Bordeaux mixture when the leaf-buds are just expanding. 



Galloway, Rep. U.S. Dept. Agric, 1887, p. 341, figs. 

 Goethe, Garienflora, 15 Mai 1887. 



PEAB SCAB 



{Fusidadium pirinum, Libert.) 



This parasite closely resembles in structure and habit 

 apple scab {Fusidadium dendriticum), and by some 

 mycologists is considered as a form of the last-named. 

 Others, however, look upon the two as distinct, but closely 

 allied. At all events, the injury done to the foliage and 

 fruit of the pear is sometimes very severe, especially during 

 a cool, damp season. 



