8o FUNGOID DISEASES 



4. Do not plant too closely, but allow light and 

 air to enter : crowded plants keep moist longer and 

 are more likely to suffer from the disease. 



5. Spray with Bordeaux Mixture (see p. 25). 



6. Collect and burn diseased haulms where this 

 is practicable. 



7. Boil diseased tubers prior to feeding. 



8. Cutting off the tops has been found to reduce 

 the disease in some cases, but results in a decrease 

 in the crop. 



9. Do not dig tubers which are to be stored until 

 at least ten days after the death of the haulms, so 

 that tubers already infected may have a chance to 

 decay, while the danger of infection of the tubers on 

 diofoinor is to a oreat extent avoided. 



II. Potato Leaf Curl [Macrosporium solaui, E. 

 e t M, ). ^ Fungi Impe j'fecti. 



Note. — This disease must not be confused with the " Leaf 

 Roll " {BlattroUkrankheit) or the " Curly Dwarf" or '' Curly Leaf" 

 {Kr'iuselh'ankheit) so prevalent on the Continent, which are not 

 caused by a fungus, l3ut are due to a physiological derangement. 



This disease is more prevalent in the United 

 States (where it is called early blight) and in 

 Continental Europe than in Great Britain, though 

 during dry seasons more harm is done to our own 

 crops than is generally imagined. 



Symptoms. — Brown irregular patches, marked by 

 concentric zones, are found on the leaves, without 



' This has been claimed to form its conidia in chains under cultural 

 conditions and would then be called Altc?'iiaria solani. 



