juiyas. I9I7 A Colletotrichum Leaf spot of Turnips 159 



water. All were inclosed in flasks for four days. No infections occur- 

 red, the wounds on both inoculated and uninoculated pods healing nor- 

 mally. 



Six sound, firm apples were washed with a i -to-500 solution of mercuric 

 chlorid, rinsed in sterile water, and placed three in each of two sterile cul- 

 ture dishes. Three were punctured with a sterile scalpel and inoculated 

 with conidia and mycelium from a culture of the turnip fungus ; and the 

 three others were punctured in a similar manner and inoculated with 

 conidia and mycelium from a culture of Glomerella cingulata from pear. 

 All were left at room temperature in the laboratory. After a month one 

 of those inoculated with G. cingulata was almost entirely decayed, and 

 each of the others so inoculated showed spots an inch or more in diameter, 

 while those inoculated with the species of Colletotrichum from turnip 

 showed only slight decay immediately within the wound. Later, as the 

 fruits began to ripen, the decay spread until the whole of each was 



involved. 



SEED INFECTION 



As previously mentioned, inoculations showed that the seed pods 

 were readily and abundantly infected. In view of the fact that it has 

 been shown that under similar conditions the mycelium of some other 

 species of this genus, notably Glomerella {Colletotrichum) lindemuthianum, 

 Shear and G. (Colletotrichum) gossypii Edgerton, enters the seed and 

 remains dormant there during dormancy of the seed, this observation was 

 of special interest; and experiments were planned to determine whether 

 this was true for the turnip fungus. 



During the spring of 191 5 several old turnip plants in the field were 

 transferred to pots and brought into the greenhouse to produce seed. 

 When seed pods of various ages, from flowers to almost mature pods, 

 had formed on a stalk the whole seed stalk was sprayed with a suspen- 

 sion of spores in water and then covered for a few days with a glass 

 cylinder. Within a short time practically every pod on the inoculated 

 plants showed one or more spots, and on many the entire surface was 

 diseased. When the seed had ripened, the stalks were cut and hung in 

 the storeroom until the experiment could be completed. 



At various times during the following fall and winter seed were care- 

 fully shelled out, counted, and planted in pots in the greenhouse. Many 

 seed from badly infested pods were plainly shrunken and dead. Less 

 than half germinated. In one lot of 500 seed planted only 14 germinated. 

 In all more than 2,000 seed were planted; but in no case could any dis- 

 eased spots be found on the cotyledons or hypocotyl of the seedlings and 

 none developed on the leaves. 



Some of the diseased seed pods were also killed, embedded in paraffin, 

 cut, and stained with various stains; but no trace of mycelium was ever 

 found in living seed. It seems that, when the fungus enters a seed, 

 the young embryo is killed at once, and the fungus probably dries up and 



