Fil.-TY-FIRST ANNUAL RKIMJRT. 30 



DECEMBER 7, 1921. 

 FORENOON. 



After a jiulfiinij; contc'st in which some twelve or fifteen Juniors and 

 Seniors of the JMichi<ian Agricultural College participated, the meeting 

 in charge of Mr. Rogers opened with the Speakers' Contest. 



Mr. J. IX \\'ilsoii of r>ansing was the fir.st speaker. 



BRAMBLE ]:)ISEASES OF MICHIGAN AND THEIR CONTROL. 



J. 1). WILSON, LANSING, MICH. 



The term brambles includes several small fruits. In this discussion 

 it will be confined to raspberries and blackberries. 



The principal diseases of brambles in Michigan are, — anthracnose, 

 cane blight, crown gall, orange rust and yellows. Anthracnose and 

 cane blight cause their greatest damage to the black raspberry. Yel- 

 lows is a disease of red raspberries and orange rust attacks the black- 

 berry. Crown gall (a bacterial disease) infects many fruits. 



Most of the diseases of brambles live over winter in the old canes and 

 rubbish about the berry patch. This fact suggests an important pos- 

 sibility. Why not cut out the old canes and burn them with the rub- 

 bish in the fall? As it happens, this is the best means of keeping most 

 of the diseases down to a minimum of infection. There is one exception 

 to this, anthracnose can be very well controlled by the use of lime sulphur. 

 With the other bramble diseases mentioned, spraying is strangely in- 

 efficient. 



Raspberry anthracnose, caused by Pectodisela veneta, occurs almost 

 universally where raspberries are grown. It is most serious on the 

 black cap. In dry seasons an almost complete loss of the crop may be 

 experienced. It often makes the renewal of the plantation necessary 

 every three or four years. 



The vegetative portion of the fungus lives over the winter in the old 

 canes. Spores are produced in the spring which cause re-infection of 

 the young canes when they are from six to eight inches high. Purple 

 spots appear on the shoots, later these spots enlarge and the center be- 

 comes grey and shrunken. The midribs of the leaves and the fruit 

 are often infected. 



By spraying with lime sulphur before the infection occurs, many 

 of the spores maj^ be killed when they germinate. A dormant applica- 

 tion (1-20) gave commercial control in experiments this year. By 

 putting on a second and third spray of 1-50, complete control may be 

 obtained. The second spray should go on when the new shoots are 

 from six to ten inches high, the third about two weeks before the canes 

 bloom. If, for any reason, it is suspected that control is not complete, 

 the canes should be carefully gone over after the fruit has been har- 

 vested and all of the infected material removed and burned. 



Cane blight, caused by Letoshaeria coniothyrium, is another serious 

 disease of black caps. It occurs over most of the Eastern U. S. It is 

 peculiar in that it causes the greatest loss in dry seasons when one-half 

 to one-third of the crop may be lost. Very often the first sign of this 

 disease, which the grower notices, is a sudden wilting of the canes. The 



