TREATMENT OF ORNAMENTAL CHESTNUT TREES AFFECTED WITH THE 



BUGHI DISEASE. 



This bulletin is intended as a guide for the treatment of individual 

 chestnut trees affected with bli^'lit, which on account of their value 

 as orchard trees or for decorative purposes warrant tlie expenditure 

 I r considerable time and money for tlieir preservation. 



DESCRIPTION OF THE DISEASE 

 The blij^ht disease is caused by a fungus which grows in the bark 

 and also in the outer layers of sapwood. Pustules (fruiting bodies) 

 are soon produced and grow through to the surface of the bark. On 

 old, rough-barked trees these pustule-s are borne in the crevices of the 

 bark, 'the pustules, of a piuhead form, are orange-yellow or saffron 

 in color, and get darker with age, at maturity being a rusty brown. 

 The spores are of two kinds and aro produced at nearly all seasons 

 of the year. They are disseminated through the agency of wind, 

 insects, birds, etc. The spores must reach the inner or middle bark 

 to cause an infection. Ordinarily they germinate very quickly, per- 

 haps in a few hours, or at most in a few days. The mycelium then 

 grows through the bark in all directions, developing a series of more 

 or less concentric rings, so that the lesion, or area of infection, has 

 a somewhat circular or oval shape. The rate of growth of the mycel- 

 ium dei)ends upon weather and other conditions. It grows at all 

 seasons of the year, except in the coldest weather, when it is dor- 

 mant. In summer, esi)ecially in June and July, it is most rapid, as 

 a temperature of about 70 degrees and upwards seems best suited for 

 its development, but growth is less rapid if the weather is dry. In 

 July and August the trees bearing dead branches are especially 

 noticeable. 



FA-KE REMEDIES 



A great number of so called "cures" for the blight have been ad- 

 vanced. In many cases the method of treatment shows that the 

 sponsor is either ignorant or unscrupulous, and in other cases the 

 work is done in such a haphazard fashion that it is entirely worth- 

 less. 



A spray cannot penetrate beneath the bark where the disease is 

 working, and consequently is absolutely worthless as a remedy. It 

 may be i)ossible, however, to find a toxic solution which can be in- 

 troduced in some way into the circulation of the tree which will 

 kill the fungus without killing the tree. The Pennsylvania Chestnut 

 Tree Blight Commission is carrying on a series of experiments with 

 this end in view, and it is hoped that some such remedy will be 

 found. It has been claimed that a proper application of ferti- 

 lizers will cure the disease. \Aliile it may be that a healthy, rapidly 



