2 20 TRANSACTIONS OF THE ILLINOIS 



shoots just appearing above ground ; some of the young leaves of these 

 we dusted thickly with mature dust or rust; on others we slightly abraded 

 the upper surface of the leaves, and after moistening tliem, rubbed a 

 rusted leaf over them. It has now been seven days since these shoots 

 were so treated ; to-day they all present the unmistakable signs common 

 to plants that become affected without artificial aid. 



TWIG BLIGHT OF THE APPLE. 



A good deal of mquiry has been made with respect to the Twig-blight 

 in apple trees. The following letter, by Mr. Daggy, and the reply, will 

 indicate what has been done in this direction : 



Dr. E. S. Hull, Alton. — Dear Sir: Enclosed please find a twig of an apple- 

 tree, showing the blight, found in a neighbor's orchard. All the trees are affected 

 more or less. This twig may not be in condition to show the character of the dis- 

 ease, but your familiarity with it may suffice. It is in spots all over the trees, from 

 the trunk to the tips of the branches — some branches entirely girdled with it; yet 

 there are green, healthy looking leaves and fruit above it; some trees (Rambo) 

 are damaged to the extent of perhaps a fifth twig all over the tree, making them 

 the worst cases I ever saw. 



The owner of this small orchard is an amateur fruit-grower, who cultivates 

 highly and prunes judiciously, but feels rather discouraged with the appearance of 

 this indication of the destruction of the tree, while the insects are taking the 

 fruit. 



Can you give us the cause, cure, or future prospects of this blight, or rather your 

 opinion and experience with it? We look to the " Farmer" for your reply. 



Tuscola, 111., June ii, 1870. E. DAGGY. 



P. S. — I cut over two inches, and four healthy looking leaves from the present 

 year's growth on the top of this twig. 



The branch of an apple tree, with the above, came to hand a day or 

 two after date. The branch was a good deal dried. We cut from it, 

 however, several small slices of bark, going deep enough to include a thin 

 slice of wood ; with these we inoculated several succulent pear shoots, by 

 tying in the pieces of bark as in budding. This was done during the 

 recent drought, when it .was not only dry, but extremely warm. These 

 conditions of course were not the most favorable to the spread of blight, 

 since in addition to heat and warmth, a humid condition of the atmos- 

 phere is also required. 



Soon after inoculating the pear shoots we were for several weeks con- 

 fined to the house by illness, and to-day (July 20th), after a lapse of thir- 

 ty-four days, by reading the communication a second time, were reminded 

 of the experiment on the pear shoots. On inspecting them, we found 

 them all blighted. 



The blight had gone above inoculated parts, varying from one half-mch 

 to two inches, and descended from three to fourteen inches, further con- 

 firmino- the opinion we have before several times expressed, that the 

 fungi causing pear and apple tree blight are identical. This disease in 

 thelwigs is not new to the apple trees, nor is it unusual to see trees which 

 are susceptible to it, made more so by late growth, as we will attempt to 

 bhow further on. 



In free-growing ti'ees this twig-blight, so called, is not confined to the 



