124 MASSACHUSETTS HORTICULTURAL SOCIETY. 



what form or in what place it passes the winter, I do not yet 

 know, bnt given one affected plant in a squash or cucumber field 

 in June or July, and plenty of beetles to feed on it, and in a 

 month or six weeks there will frequently be more diseased than 

 healthy plants. That all are not destroyed by it appears to be 

 due largely, if not wholly, to the fact that it is readily killed by 

 exposure to sunlight and to dry air. 



Bacterial Broivn Rot of the Potato, Tomato, and Egg-Flant. — 

 The Department of Agriculture has recently published a bulletin 

 on this disease, which some of you may have seen. This disease 

 is also disseminated by insects, and in all probability owes the 

 greater part of its destructiveness to this fact. The insects feed 

 on diseased plants that are swarming with the parasite and then 

 crawl or fly to other plants, which are bitten and subsequently 

 become diseased. I do not yet know how widespread this dis- 

 ease may be, but am now inclined to attribute to it a large part 

 of the potato rot of the eastern United States. It may be known 

 by the sudden wilt of the foliage, the stems becoming brown 

 internally and shrivelling. The bacillus passes down the inte- 

 rior of the stem into the tubers, and brown-rots them from within. 

 I succeeded in communicating this disease from sick to healthy 

 plants very readily by means of Colorado potato beetles. They 

 Avere taken from healthy potato fields which remained healthy, 

 were allowed to feed on diseased leaves and stems for a few 

 hours and then transferred to healthy plants, which they gnawed 

 a little in various places, but from which the beetles were re- 

 moved before they had done any serious injury of that sort. 

 Seven to nine days later the plants suddenly developed the dis- 

 ease on many parts of the top, corresponding to many bites, and 

 the progress of th6 disease after the first day or two was rapid. 

 As the spread of this disease is simply a matter of the transfer 

 of a few germs from the interior of diseased to the interior of 

 healthy plants, I do not see why any gnawing or puncturing 

 insect might not serve just as well as the potato beetle as a 

 carrier of this disease.' 



Spread by Snails and Slugs. — The role of mollusks in the 

 dissemination of fungous and bacterial diseases is also an impor- 



» As this paper goes through the press (Feb., 1898), Dr. W. C. Sturgis, of the Connecticut 

 Agricultural Experiment Station, reports the interesting discovery that the mildew of Lima 

 beans {Phytophthora Phaseoli, Thaxter) is disseminated by bees which visit the flowers for 

 nectar. 



