1917] DISEASES OF PLANTS. 351 



were obtained with the three liquid sprays iron sulphid, atomic sulphur, and 

 milled sulphur on grapevines and peach trees. The experiments with apple 

 trees, though apparently beneficial, are considered to require confirmation by 

 further tests. 



Com.parative dusting and spraying experiments, D. Reddick and C. R. 

 Crosby OVest. N. Y. Hort. Soc. Proc, 60 {1915), pp. 68-77 ) .—These tests related 

 mainly to insect control, the only disease amenable to the treatments given 

 being apple scab. This trouble was pronounced in some localities in 1913 and 

 very general in 1914. 



It is said that the time of application is most important. The dust method 

 is deemed applicable in case of large, old trees, where it is most needed, is from 

 three to six times as rapid as that of spraying, and the total cost for dusting 

 per tree is not greater than for spraying. The mixture, of which 2 to 3 lbs. 

 should be applied to each tree at each time, is 90 per cent sulphur and 10 per 

 cent lead arsenate, the latter being intended for insects. 



No reports of injury from breathing the dust have been received. The 

 sprayer is recommended in case of apple varieties which are very susceptible 

 to scab. 



See also the bulletin already noted (E. S. R., 34, p. 738). 



Note on apple root rot in Virginia, G. H. Ckabill (Phytopathology, 6 {1916), 

 No. 2, pp. 159-161, fig. 1). — The author states that the root rot previously de- 

 scribed (E. S. R., 33, p. 544) is quite prevalent in the Shenandoah Valley and 

 Piedmont section of Virginia. It is more prevalent on new ground, especially 

 v.here the soil contains decaying wood, and is present in a wide variety of soils 

 and in many localities. In many orchards, several adjoining trees appear to 

 have contracted the disease at about the same time. Some varieties of apples 

 are said to be very susceptible, while others are less liable to attack. 



The roots of the infected trees were found to be infested with a delicate white 

 myceliiun, and the fungus has been identified as Trichoderma kocningi. While 

 the organism is generally considered a wound parasite, the author believes that 

 there is some evidence that it occurs on apple roots as a parasite. 



Apple rosette, O. M. Morris {Rpt. Wash. State Hort. Assoc, 12 {1915), pp. 

 69-72). — Reporting briefly the results of a survey by correspondence extending 

 over several States, the author holds that apple rosette is somehow connected 

 with the nutrition of the plant. While treatment in some sections should 

 look to improving the humus content of the soil, different means must be 

 employed in other sections, such as drainage and improvement of physical 

 condition. 



Sulphur paste as a spray for peaches, D. Reddick {Phytopathology, 6 {1916), 

 No. 2, pp. 206, 207). — Attention is called to the ease of preparation and excel- 

 lent suspension of sulphur paste, which is said to be quite efficient for the con- 

 trol of brown rot and scab of peaches. Directions for the preparation of the 

 paste are given. 



Pear blight (Bacillus amylovorus), T. O. Morrison {Rpt. Wash. State Hort. 

 Assoc, 12 {1915), pp. 131-133). — This is part of a report by the author on hor- 

 ticultural field conditions in 1915, and deals with the progress at various points 

 during the year of B. amylovortis, the cause of fire blight. This is tliought to 

 have reached its highest mark during 1914 and to be now somewhat on the 

 decline, which may possibly be accelerated by imiform control measures 

 throughout* the orchard districts. 



Further studies in the role of insects in the dissemination of fire blight 

 bacteria, V. B. Stewart and M. D. Leonard {PhytojHithologu, 6 {1916), No. 2, 

 pp. 152-158). — During the summer of 1915 tbe authors carried on experiments 

 with Pollenia riidis, Empoasca mali, Psylla pyricola, Plagiognathus politus, and 



