69 



when such peas are planted, the fungus immediately develops 



and rots the peas, thus reducing the per cent, of germination. 



Of those peas which do germinate, many do not get through the 



ground. In other cases, the pea comes up only to be attacked 



later by the fungus, which either kills or injures the stem near 



the growing tip or produces lesions on the stem. Fi'^. i, a, 



shows such a lesion a little more than half way up the stem. It 



is not always necessary for the terminal bud or the stem to be 



killed in order to produce development of the axillary buds at 



the base of stem, as a very slight lesion on the side of the stem 



often suffices. Scores of such cases have been observed where 



the primary stem seemed still healthy. Furthermore, not only 



do the buds m the axils of the two cotyledons develop, but other 



adventitious shoots appear from the same region. These may 



either appear when the disease attacks the secondary shoots or 



at the same time as those from the axils of the cotyledons. 



Frequently as many as six shoots developed when the primary 



stem was injured. Fig. i, b, shows three secondary stems ; 



these, in turn were all killed by the fungus at the tip and a fourth 



shoot was just starting. 



Sometimes considerable difficulty is experienced in obtaining 



good germination with peas for botany classes. In view of the 



failure to grow because of the blight fungus, as well as from 



other fungi and bacteria, it is suggested that all discolored peas 



be thrown out ; that the soil be sterilized or a new or less organic 



soil be substituted ; and that the soil should not be kept too wet. 



Seed treatment before planting by the use of heat or chemicals 



has proved a failure, since the fungus is zvithin the pea seed and 



anything used as a fungicide kills the pea germ before it kills 



the fungus. 



Ohio Agricultural Experiment Station, 

 WoosTER, Ohio. 



