274 TIMBER AND SOME OF ITS DISEASES. [CHAP. 



to fall prostrate on the surface of the soil ; in y< 

 others, the lower parts of the stem of the older s( 

 ling may be blackened, and dark flecks appear 

 the cotyledons and young leaves, which may al 

 turn brown and shrivel up (Fig. 42). 



If the weather is moist e.g. during a rainy May 

 June the disease may be observed spreading rapi< 

 from a given centre or centres, in ever-widening circl< 

 It has also been noticed that if a moving body pas< 

 across a diseased patch into the neighbouring health} 

 seedlings, the disease in a few hours is observed 

 spreading in its track. It has also been found that 

 seeds are again sown in the following season in 

 seed-bed which had previously contained many 

 the above diseased seedlings, the new seedlings wi 

 inevitably be killed by this "damping off." As 

 shall see shortly, this is because the resting spores 

 the fungus remain dormant in the soil after the deal 

 of the seedlings. 



In other words, the disease is infectious, and spreac 

 centrifugally from one diseased seedling to anottu 

 or from one crop to another : if the weather is moi< 

 and warm " muggy," as it is often termed such 

 often occurs in the cloudy days of a wet May or June 

 the spread of the disease may be so rapid that evei 

 plant in the bed is infected in the course of two 



