260 EXPERIMENT STATION RECORD. 



DISEASES OF PLANTS. 



Report of the mycologist, F. C. Stewart (New York State Sta. 

 Bpt. 1896, pp. 447-521, pis. 4). — The author gives a review of the year's 

 work, the most of which has been published in bulletin form. 



Notes are given on several miscellaneous plant diseases that have 

 been noticed by the author. A disease of turnip leaves which was due 

 to Macrosporium herculeum is figured and described at some length. 

 The fungus produces circular, brittle, dead spots on the leaves and 

 when the spots are numerous the leaves wither and fall off. While 

 many of the species of Macrosporium are saprophytic, this species, the 

 author states, is undoubtedly a parasite. A similar disease is reported 

 on the foliage of horse-radish during the summer. However, it is not 

 thought that either on the turnip or horse-radish will sufficient injury 

 be done to warrant the expense of spraying. 



A blight of corn leaves, the primary cause of which is attributed to 

 the parasitic fungus Helminthosporium inconspicuum, has caused con- 

 siderable injury in some localities. The diseased leaves have some- 

 what the appearance of having been frosted. If the surface of the 

 leaves beneath the diseased spots be examined it will be found covered 

 with a delicate, olive-green mold. This disease is said to attack both 

 sweet and field corn. There is a disease of sweet corn due to bacteria 

 which might be mistaken for this disease. The latter disease makes 

 its appearance early in the season, while Helminthosporium inconspicuum 

 usually does not appear until August. No practical remedy is sug- 

 gested. The bacterial disease has been fully described in Bulletin 130 

 of the station (E. S. R., 9, p. 1056). 



The author describes an injury of the foliage of Norway maples which 

 is attributed to the action of dry winds, the entire foliage of some trees 

 being scorched as if by fire or as though killed by a heavy frost. For 

 a period of about a week previous to the appearance of the injury the 

 temperature had been unusually high and during the last three days 

 strong dry winds had blown steadily from the West. The explanation 

 of the injury is that it is due to a disturbance in the transpiration of 

 the trees. In addition to the Norway maple, white pine, pear, and 

 apple trees were slightly injured by the same cause. 



Brief notes are given on a leaf-spot disease of linden due to Cercos- 

 pora microsora, a leaf spot of apples due to Phyllosticta limitata, two 

 diseases of sunflowers caused by Septoria helianthi and Puccinia helian- 

 thi, a disease of the horse-chestnut caused by Phyllosticta sphceropsoidea, 

 a sycamore disease caused by Glceosporium nervisequum, asparagus rust, 

 and a clover rust which are described in more or less detail, all of them 

 having proved injurious during the year. The author also reports 

 the occurrence or additional localities for Hxoascus cerasi, Exobasidium 

 peckii, and Bamularia cylindriopsis. 



Reports are made on the work in combating carnation rust, which 

 was published as Bulletin 100 of the station (E. S. B., 8, p. 238), potato 



