DISEASES OF PLANTS. 55 



On the germination of almonds (Rev. Gen. Bot., 9 (ISO?), No. 1, pp. 5-16). 



Danish seed control, 1871-'96, 0. Rostrup (Dansk Frbkontrol. Copenhagen, 1896, 

 pp. S3). — A resumd of results and methods of Danish seed control puhlished on the 

 occasion of the twenty-fifth anuiversity of the seed-control station in Copenhagen 

 in 1896. A chapter is devoted to seed-control stations in foreign countries, a list of 

 which is given, with year of establishment, name of director, etc. 



DISEASES OF PLANTS. 



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

 Rpt. 1895, }>}>. 519-546, figs. 5). — The following subjects are discussed 

 in this report: (1) Two destructive lily diseases; (2) prevention of cab- 

 bage club root: (3) spraying tomatoes; (4) a disease of Norway 

 maples; (5) witches' brooms on cherry trees; (0) observations on fj.ro- 

 basidium pecJcii and Ramularia cylindriopsis ; (7) inoculation experi- 

 ments with Gymnosporangium macropus; (8) "belted" apples and 

 pears, and (9) a new leaf spot disease of apples. 



The first lily disease described is said to have been known for sev- 

 eral years, and has gradually grown worse until it threatens the com- 

 plete destruction of the Easter lily industry. It is characterized as 

 follows : 



'■ Very soon after the leaves start thej show hlotches and streaks of light yellow. 

 As the plant develops the yellow blotches are gradually replaced by numerous small, 

 irregular, dead spots, giving the leaf the appearance of having been gnawed by 

 insects. The flowers are spotted in the same manner. The whole plant presents a 

 sickly, yellowish, rusty appearance, making it unsalable. In many cases the plants 

 never flower ; in others the Sowers are distorted. The disease progresses very slowly. 

 The bulb appears to lie normal, 1 < 1 1 1 the tips of the feeding roots are found to be 

 dead. If a healthy plant is knocked out of its pot, the hall of dirt appears white 

 all over the outside with growing rootlets. A diseased plant similarly treated shows 

 very few white rootlets.'' 



The cause of the disease is obscure. Cultures made from leaves 

 and buds develop various fungi and bacteria, but no one species 

 appeared constantly. It is thought probable that when the cause of 

 the disease is determined it will be found to be some organism living in 

 the soil which prevents the roots from performing their proper function. 

 Upon this hypothesis the author suggests the following treatment: 

 (1) Never use soil in which lilies or other bulbous plants have ever 

 been grown, and (2) previous to potting soak the bulbs for 14 hours in 

 a weak solution of corrosive sublimate. 



The second lily disease mentioned is that known as the Bermuda 

 lily disease, which attacks several varieties of lilies grown in the open 

 air. The disease is caused by a parasitic fungus, Botrytis sp., and its 

 characteristics as observed on its host are mentioned. Experiments 

 with Bordeaux mixture seem to indicate that spraying at intervals of 

 10 days or 2 weeks, commencing with the appearance of the leaves and 

 continuing until the flowers begin to open, will prevent attacks of the 

 fungus. The spraying must be discontinued with the opening of the 

 flowers, otherwise the fungicide will spot them. 



