39 



the most active agent in the spread of mildew. If a few leaves become 

 infected in the house when the bees are active, it does not take a great 

 while for tiiem to infect the whole crop. Care should be taken in such 

 cases to destroy the first signs of mildew as it appears. 



Timber Rot (Schlerotmia Liber liana Fckl.). — This disease is com- 

 mon to both cucumbers and tomatoes. It attacks the stem, causing a 

 shrivelled, dry and lifeless a^jpearance of that portion affected Black 

 masses, or sclerotia, which are about ^^ to ^\ inch in diameter, appear 

 on the sui'face of the affected region. These will germinate and infect 

 other plants, if the conditions are favorable. The fungus which pro- 

 duces the timber rot is confined to the soil, and is supposed to be the 

 same as that which causes the so-called " drop "' in lettuce. It does not, 

 however, cause very much damage to cucumbers and tomatoes, as a 

 rule. Should it ever become serious, the only remedy to apply will be 

 to sterilize the soil. Under the most favorable conditions this method 

 of treatment can be applied at a low cost at the present time, and, when 

 thoi'oughly done, it constitutes an absolutely positive remed}' for this 

 and other diseases that have their origin in the soil. 



Damping off (Pyihiuni De Baryanum Hesse.). — Seedling cucumbers 

 very frequently damp oft' when placed under unfavorable conditions. 

 The principal unfavorable conditions which give rise to damping oft' are 

 lack of light, too close planting, too much heat and moisture, — or, in 

 fact, anything which tends to produce weak, spindling seedlings. For 

 this troublesome disease the method of prevention is obvious, viz , to 

 eliminate the conditions which favor the growth of the fungus. Damp- 

 ing off almost invariably occurs on seedlings, and seldom aftects plants 

 which have developed a leader 5 or 6 inches long. If it is necessary to 

 force seedlings, or i)lace them under conditions which favor the develop- 

 ment of the damping fungus, a positive prevention can be had in steril- 

 izing the soil. Since the amount of soil which is necessaiy to start 

 many hundreds of seedlings is small, this method of treatment can be 

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

 remedy for damping off, the germination of the seed and development 

 of the plant will be greatly accelerated. 



Downy Mildew (Plasmopard Cubensis (B. & C.) Humphrey). — 

 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 ])resent each year 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 history 

 of this mildew, as it is not known positively where it originated, nor 

 why 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 occurrence on 

 greenhouse plants is not, however, of serious consequence, as it appears 

 only on crops that are planted early, and no record of its appearance 

 later than December is known in this State. We have never known 

 indoor cucumbers started in October or November to be affected with 

 this fungus, but those started in August or September are likely to be. 



