FILBERT OR HAZELNUT. 



141 



weeks or months before the pustules appear, for these 

 are merely indications of the last stage in the life of the 

 fungus, and with the throwing off the spores from these 

 pustules the old parasite perishes. 



The pustules, when fully open, are from one-six- 

 teenth to one-eighth of an inch in diam- 

 eter, usually round, but sometimes slightly 

 oval in form, and placed mainly in almost 

 straight rows lengthways of the branch, as 

 shown in Fig. 44. These pustules appear 

 on wood of all ages, from two years upward, 

 and in what may be termed patches, rang- 

 ing from a few inches to a foot or more in 

 length, and more frequently on the upper 

 side than the underside of the branches. 



This fungus is undoubtedly indige- 

 nous, and its host plant is the common 

 American hazel (G. Americana). From a 

 very careful search, I have not been able to 

 find any clump of these bushes of any con- 

 siderable size that was entirely free from 

 pustulous stems. But on these wild plants 

 it seems to do but little harm, for if a stem 

 is killed, another soon springs up from the 

 roots to take its place ; but when-this fun- 

 gus invades our orchards and gardens and 

 attacks filbert trees, we recognize it as an 

 implacable enemy. How far the spores of 

 this fungus are likely to be carried by the 

 wind, transported on the clothes of a per- 

 son, or the hair of domestic animals, I do 

 not know, but it certainly is not safe to FIG, 44. 

 plant the susceptible species and varieties HAZEL FUNGUS. 

 within a mile of the wild hazel bushes, unless the planter 

 is prepared to use fungicides freely on his trees. There 

 are certain phases of this filbert blight that are rather 



