2IO MINNESOTA STATE HORTICULTURAL SOCIETY. 



the Wisconsin Horticultural Society in 1881, stating that only trees 

 that were in blossom on two particular days of the preceding spring 

 were blighted, and even sends specimens of the blighted blossoms to 

 Prof. Burrill — who pronounces the affection blight — little thought 

 seems to have been given the matter of blossom blight till it was 

 taken up by Mr. Waite. 



For successful inoculation of buds, growing tips, young shoots 

 and fruit, a puncture had been found necessary to get the bacteria 

 through the hard covering. Waite tried inoculating blossoms with- 

 out puncture by dipping a camel's hair brush in liquid containing 

 the bacteria and touching the center of the flower. He was success- 

 ful in producing the blight. When watching one of these blossoms 

 one day he noticed a bee light upon it and begin feeding. Since the 

 bacteria grow and multiply in the nectaries of flowers, he asked him- 

 self why this bee rhight not carry some to the next flower it visited 

 and inoculate that as he had this — with his brush. To test this 

 he captured two bees and from them got cultures with which he 

 successfully produced blight. Here he thought was an explanation 

 of how a whole orchard might become affected within a few days, 

 at blossoming time. To test the matter thoroughly he obtained an 

 orchard in western New York, free from blight, started artificially an 

 epidemic of blight by inoculation, protecting certain flowers by 

 covering with bags of mosquito netting, thus leaving them exposed 

 to the wind but protected from the visit of insects. He asserts that 

 in no case did he get an infection within the mosquito netting, while 

 there were plenty of infections outside. 



Mr. Waite claims that the bacillus amylovorus will not stand 

 drought for a week but will stand hard freezing, those grown in 

 a warm room suffering no injury from a temperature of o degrees F. 

 He therefore concludes that very few live through the winter, only 

 those at work within the branch when the season closes. These, 

 when the warm sun in the spring starts a strong flow of sap, begin 

 active work and multiply rapidly. As a result of their action a 

 gummy exudation takes place. Various insects feed upon this, and 

 if it happens to be at blossoming time their visits to the flowers 

 spread the disease over an orchard in a short time. 



To summarize briefly, for we cannot within the scope of this 

 paper follow out other investigations, the general consensus of opin- 

 ion at the present time is that apple blight is a bacterial disease 

 caused by bacillus amylovorus, feeding under cover of an outer layer, 

 and therefore that it cannot be destroyed by spraying; that the in- 

 jury is caused by the parasite itself and not by any by-products 

 formed ; that the only remedy is to remove with the knife all blighted 



