if^Ew YoKK Agricultural Experiment Station. 197 



knot. In the central part of Rensselaer Co. we have examined 

 the choke cherry, Prunus virginiana L., which grows wild there, 

 but found no knots upon it. However, at Washingtonville, Orange 

 Co., the latter species is said to be much affected. 



What has been said applies only to old knots. The observa- 

 tions furnish no information as to the number of knots produced 

 by infections occurring in 1899, for the new knots do not appear 

 until late in autumn, after the time when the survey was finished. 



witches^ brooms. 



(Exoascus cerasi (Fckl.) Sadeb.) 



Knowing that this disease is not uncommon in some other parts 

 of the State^^ we expected to find it in the Hudson Valley, but 

 failed to find a single specimen. 



POWDERY MILDEW. 



(Podosphaera oxyacanthae (D. C.) De By.) 

 On July 20, a single bearing cherry tree affected with powdery 

 mildew was observed at Delmar, Albany Co. A few leaves at 

 the ends of the twigs were affected. 



FUNGUS ON DEAD TRUNKS. 



(Irpex lacteus Fr.) 



On a fruit farm at Middle Hope we observed many dead cherry 

 trees bearing numerous pilei of Irpex lacteus Yy}*^ The trunks 

 were from three to five inches in diameter and in many cases were 

 thickly covered with the fungiis to a height of from three to five 

 feet. The OT\Tier explained that the trees were of the variety 

 Elkhorn, which is not hardy. Most of the trees had died during 

 the past three or four years, apparently from winter injury. 



15 See Fourteenth Ann. Ecpt. of this station, 1895: 532-533; also, Fifteenth 

 Kept., 1896: 459. In May, 1899, we found a single large specimen on an ox- 

 heart cherry [Prunus avium), at Sodus Center, in Wayne county, about five 

 miles from the shore of Lake Ontario. 



16 Identified by Dr. C. H. Peck. 



