IINDIANA HORTICULTURAL SOCIETY. 363 



and has thrown much light on the subject of blight aud largely cleared 

 the atmosphere of doubt and uncertainty heretofore prevailing. Professor 

 Burrill, like most of his predecessors, seems to have been exhausted here, 

 and sat down to rest, and as far as linown remains in statu quo. 



Recently Mr. M. B. Waite, of the Division of Vegetable Physiology 

 and Pathology of the U. S. Department of Agriculture, has made (?) a 

 special study of pear blight, and added much to the knowledge of the 

 nature, spread and control of the disease. 



Mr. Waite says one of the most remarkable things about the disease 

 is the rapidity Avith which it spreads through an orchard at blooming 

 time. This peculiarity has thrown much light on the way microbes 

 travel about, which they do quite readily, notwithstanding they are sur- 

 rounded and held together and to the tree by sticky and gummy sub- 

 stances. They are able to live and multiply in the nectar of the 

 blossoms, whence they are carried away by bees and other insects from 

 blossom to blossom until whole orchards are inoculated. From the blos- 

 soms the disease extends downward into the twigs, limbs and trees. An- 

 other way in which trees are inoculated is tlirough the tips of growing 

 shoots. This is called twig blight, to distinguish it from blossom blight. 

 Mr. Waite thus describes the action and progress of the disease: 



"The blight begins on the blossoms in early spring; then during the 

 summer we may have twig blight clear into September. The disease runs 

 down on the twigs, and in the majority of cases dies out. The disease 

 works in the bark, and as a rule tinds the tree, at some time during the 

 late spring and summer, too dry and tough for it to take hold of, and it 

 dies out. Occasionally, however, infections keep running down on the 

 twigs, get into the fleshy bark and keep on working slowly till fall. After 

 this season of the year the trees are .so moist that those germs will not 

 dry out, but will live over winter, resulting in "hold-over" blight. It 

 stands the zeros perfectly. In spring the hold-over cases start off when 

 root pressure begins, and when the tree is full of sap. In this way the 

 disease is perpetuated." 



Mr. Waite suggests no new remedies in his treatises as far as I have 

 had time to search. 



The California State Board of Horticulture has recently had an agent 

 at work on this disease, who. after thoroughly investigating the matter 

 under all the available knowledge of recent discoveries, comes to the 

 following conclusions: 



First. The principal point of entry or inoculation is through the blos- 

 soms, and its progress is downward, varying in speed from an inch to 

 several inches daily. 



Second. The healthiest trees— those making the most vigorous growth 

 —are the most susceptible to attack. 



Third. The disease is common to the wliole poniaceous family. 



