DISEASES OF CULTIVATED PLANTS 633 



were soaked in sulphur solution for two to five hours, and while all 

 the mites reached were killed, those protected by the tissues of the 

 bulb escaped. When bulbs were soaked two hours in corrosive sub- 

 limate (1/1000 to 1/2000) the mites were not all reached and the 

 bulbs were injured. Soaking two hours in formalin (1/1000 to 

 1/2000) was not effective and the bulbs were injured. Fumigating 

 with hydrocyanic acid gas (one-tenth gram of 50 per cent KCN per 

 cubic foot of space) for three hours was not effective, although all the 

 mites reached by the gas were killed. It is probable that this gas can 

 be used much stronger than it has yet been tried and may give better 

 results. It is extremely important that the mites and aphides be 

 kept off the plants from the start, for if they once get a foothold it 

 is almost impossible to get rid of them without injuring the plants. 

 The pots may be plunged in coarse coal ashes and the tops mulched 

 with tobacco stems to keep down these pests. When smoking can 

 not be resorted to, a liberal supply of tobacco stems or dust should be 

 used. 



The bulbs to be forced should be planted in well-drained, well- 

 aerated soil, containing not more than one-fourth well-rotted organic 

 manure. The roots, as well as the bulbs, require a large amount of 

 oxygen and this they can not obtain if the soil is too wet. Great 

 care should be exercised in watering to keep the water off the young 

 foliage, for, as above stated, the latter is often injured by the water 

 being injected into the intercellular spaces or remaining on the 

 leaves for some time. The houses should be kept well ventilated in 

 order to insure strong plants. 



In feeding, solutions of organic fertilizers, like cow, horse, or 

 sheep manure, should be avoided if possible, as they have a tendency 

 to clog the soil. Chemical fertilizers in weak solution will probably 

 give superior results, although this question must be determined by 

 more extensive experiment. 



Summary. (1) The lily disease is characterized by the spot- 

 ting and distortion of the leaves and flowers and usually the stunting 

 of the plant. 



(2) The disease is quite serious on Lilium longiflorum and L. 

 harrisii and also attacks L. auratum and L. candidum. It is very 

 prevalent in Bermuda; and in the United States where the bulbs are 

 forced, it destroys from 20 to 60 per cent of the crop. It also doubt- 

 less occurs in Japan, France, and the Netherlands. 



(3) There are many theories as to the cause of the lily disease, 

 the principal ones being worn-out soil, premature removal of flowers 

 and flower stems, premature harvesting of the bulbs, carelessness in 

 the selection of stock for propagating purposes, bad treatment during 

 forcing, and the work of insects. (B. Veg. Path. 19.) 



PELARGONIUM. 



Dropsy. Some varieties of cultivated pelargonium, possibly 

 called begonia, suffer seriously from dropsy. One bright scarlet 

 flowered variety in particular has been cultivated at the Station. It 

 often suffers from dead spots in the leaves. Before these spots in the, 

 leaves die, examination will show that there are wet looking 



