AXD OTHKR IXJIKKKT.S INSECTS OF I9O7 AXl) KjoS. 67 



vious year either to tlic fact tliat they were more resistant varieties, or that 

 the dry weather this year largely prevented infection. There is no possible 

 doubt any more as to the cause of the ordinary crown-gall. Although Ur. 

 Townsend and myself have not published any very lengthy disquisition on 

 the subject, that is not because we have not worked lengthily on it, and in 

 due time we shall ha\-e out a bulletin. The appearance of the disease in a 

 worse form in another part of the nursery on what you state to be similar 

 kind of ground in plants transplanted from the infested ground the previous 

 year, I would explain as possibly due to the fact that the soil, while similar, 

 is not identical, but perhaps moister. Of course, if the plants were trans- 

 planted from the infected land they would carry with them sufficient num- 

 ber of the bacteria to explain the infections, and all that would be neces- 

 sary would be right soil conditions, that is, enough moisture. 



"I will say to j'ou personallj' that we liave reproduced the crown-gall 

 hundreds of times with pure cultures of our bacteria. We have cultivated 

 out the organism from galls tlius produced, and have reinoculated the same 

 many times, obtaining galls again, and from these galls we have again cul- 

 tivated out the organism and reproduced the disease. We have made a 

 good many cross-inoculations also from one plant to another, but this part 

 of our work has not 3'et been completed. With susceptible plants and 

 young cultures we have a number of times obtained a hundred per cent of 

 infections and none on the checks." 



The Minnesota inspector feels that he must, for the good of the 

 ntirserymen, as well as for their patrons, fall in line with the inspectors 

 of other states, and follow their example. He feels that there is oc- 

 casion for special efifort in preventing the increase of crown gall in 

 Minnesota. He feels sure, further, that all nurserymen will heartily 

 co-operate, not only to protect their patrons, but themselves as well. 

 What, then, can they do to aid in stamping out this disease? They 

 (and citizens generally) can refuse to buy any raspberries from a 

 nursery known to have crown gall. They should refrain for several 

 years, from using ground wherein affected stock has been found for 

 such crops as raspberries, blackberries, plums, or cherries, keeping 

 it free for some time of all brambles wild and cultivated. But scien- 

 tific and practical workers, agree that apples cannot readily contract 

 the disease from the above fruits, hence we believe apples might be 

 planted with safety in such ground. Affected vines should be de- 

 stroyed by burning as soon as found and where such affected vines 

 are numerous, the stock in the entire block where they occur should 

 be burned for reasons given above. Finally, nurserymen can follow 

 faithfully and generously the suggestions of the inspector or his repre- 

 sentative, even though the pocket book is for a time affected. Treat- 

 ment, be it said, must be preventive rather than curative. 



