EXPERIMENT STATION REPORTS. 315 



eaine about largely from Septoria bliglil, aggravated by delays on the 

 l)art of tlie carrier, some idea of the magnitude of tlie losses can be seen. 

 Many growers did not try to slii[) their third (or main) crop. Celery as 

 seen in the market was small, due to tlie trimming necessitated by the 

 blighting of the outer stalks. 



Early Blight was found doing enormous damage in the susceptible 

 varieties of green celery, particularly ]S'eweirs Market. In many sec- 

 tions during the hot weather of July and August this disease and not 

 Septoria was important. Hpotling of the leaves and cankering of the 

 stalks characterize<l the heavy infestations. The correlation of this dis- 

 ease with hot weather seems to fit the previously observed Southern dis- 

 tribution of the trouble. 



LEGUMES. 



Stveet Clover: 



Ascochyta caulicola was found in several locations in Michigan. The 

 P3^cnidia of the fungus were found on the old stalks of the preceding 

 year, and their i)reseuce served as a source of new infection. At present 

 sweet clover is not widely jjlanted as a forage crop, but with increased 

 use of this promising plant the Stem Blight may be very important. The 

 fungus does not differ from that described by Laubert (Arb. Biol. Abt. 

 f. Land, und Forstwirtschaft 3 :441, 1903.) 



Pea: 



The Septoria disease of pea was found severe in gardens near the 

 college. The disease appeared on the first leaves and quickly spread to 

 the stems and eventually to the pods. While seed transference of the dis- 

 ease seemed likely, the relation of trash was not completely eliminated. 



A bacterial disease of peas has been collected at the station for more 

 than 3 years. It seems to be increasing in severity'. Blotched or girdled 

 stems, spotted leaves, with smooth greasy brown spots, and gnarled cir- 

 cular, sunken spots on the pods are characteristics of this disease. Its 

 importance is as yet unknown, but it bids fair to become as serious as 

 Bean Blight is to the bean crop. 



Bean Blight and Bean Anthracnose were important the first half of 

 the season in causing poor stand and seedling injuiy. As the dry 

 Aveather came on, Bean Anthracnose largely disappeared and caused 

 but little spotting of the seed beans. Bean Blight on the contrary as- 

 sumed enormous proportions and caused wholesale injury to the leaves. 

 Seed beans sent in for examination by the laboratory showed an un- 

 usualh' high percentage of yellowed, shrivelled seeds. 



Well's Bed Kidney beans brought into the state for a test of Anthrac- 

 nose resistance were in many sections a failure due to the severity of 

 Bean Blight. 



A Bean Mosaic which has been seen on plants here and there for sev- 

 eral years assumed last year an extremely important role. Whole fields 

 were seen in which not a healthy plant could be found. This was 

 ■especially noteworthy at one seed farm where a certain wax variety was 

 being increased. Mr. S. P. Doolittle of this department reported in Sep- 

 tember successful inoculation exi)eriments in which juice from diseased 

 plants was used to convey the disease to healthy plants. 



The increasing importance of Mosaic diseases in general, the develop- 

 ment of these new and unexpected epidemic troubles, indicates a field of 

 work, worthy of scientific stud3^ 



