422 BOARD OF AGRICULTURE. [Pub. Doc. 



the most favorable conditions this metiiod of treatment can 

 be applied at a low cost at the present time, and, "when 

 thoroughh" done, it constitutes an absolutely positive remed}'^ 

 for this and other diseases that have their origin in the soil. 



Damping off (^PytJinwi De Baryanum Hesse.). — Seed- 

 ling cucumbers very frequently damp off Avhen })laced under 

 unfavorable conditions. The principal unfavorable condi- 

 tions which give ]-ise to damping off are lack of light, too 

 close planting, too much heat and moisture, — or, in fact, 

 anything Avhich tends to produce weak, spindling seedlings. 

 For this troublesome disease the method of prevention is 

 obvious, viz., to eliminate the conditions which favor the 

 groAvth of the fungus. Damping off almost invariably 

 occurs on seedlings, and seldom affects plants which have 

 deA'eloped a leader five or six inches long. If it is neces- 

 sary to force seedlings, or place them under conditions 

 which favor the development of the damping fungus, a-posi- 

 tive prevention can be had in sterilizing the soil. Since tho 

 amount of soil which is necessary to start many hundreds 

 of seedlings is small, this method of treatment can be 

 applied at an insignificant cost, and, besides acting as an 

 efficient remedy for damping off, the germination of the 

 seed and development of the plant will be greatly accele- 

 rated. 



DoAVNV Mildew (^PJa.wiopara Cnhensis (B. & C.) II um- 

 j)hrey) . — This mildew made its appearance for the first 

 time in Massachusetts in 1890, and it was not observed 

 again until 1899. Since this latter date it has been present 

 each 3^ear in both indoor and outdoor cucumbers and melons. 

 It does the most damage, however, to outdoor crops of 

 cucumbers and melons. There is something peculiar in the 

 histoiy of this mildew, as it is not known positively where 

 it originated, nor Avhy it should appear so suddenly over a 

 wide area. The mildew can be seen on the under side of 

 the leaves, and its identification can best be established, 

 with the naked eye, by the characteristic small whitish or 

 yellow angular spots which occur on the leaves. Its occur- 

 rence on greenhouse plants is not, however, of serious con- 

 sequence, as it ai:)pears only on crops that are planted early, 



