Decembee 10, 1903. 



The Weekly Florists' Review, 



121 



Chjistmas Plant Arrargcments at the Store of C. A. Samuekon, Chicago. 



trained gardener. Some of the most 

 troublesome and disastrous diseases are 

 ontirely controlled by the intelligent uti- 

 lization of these factors, and others, 

 which are more or less common, could 

 no doubt be controlled or greatly alle- 

 viated if modifications in the methods of 

 growing certain crops were practicable. 



The benefieial results which have come 

 from spraying outdoor crops have unfor- 

 tunately, been the means of inducing 

 some to believe that this is the only 

 method of treating plant diseases, and 

 where spraying is not recommended as a 

 remedy their enthusiasm diminishes:-, be- 

 cause they cannot conceive of any other 

 method of treatment. We have grown 

 for some years many experimental crops 

 in the greenhouse, and we have seldom 

 hail occasion to see the need of applying 

 spraying mixtures to greenhouse crops. 

 In the elimination of disease from green- 

 house crops, the ultimate aim should be 

 to select varieties of plants which will 

 prove immune from, as well as to study 

 and devise conditions which will not fa- 

 vor the development of diseases. The 

 most perfect and hardiest plant organ- 

 ism can become diseased in a remarka- 

 bly short time if the conditions that are 

 suitable for its normal requirements are 

 changed. 



We all have observed, no doubt, how 

 the master craftsman will select his 

 stock and create something w-orthy of at- 

 tention, where another less skilled^ will 

 start with the same material and his 

 product will be a lot of poor, sickly spec- 

 imens, adapted only to the confines of 

 the clinic or the show case of some path- 

 ological museum. The latter has felt 

 obliged to doctor his plants with the 

 standard mixtures, but would it not have 

 been better if his time had been spent in 

 obtaining a little more practical knowl- 

 edge pertaining to the growing of 



healthy plants, and devoting less atten- 

 tion to securing the knowledge of de- 

 coctions? 



The appearance of some of our 

 most troublesome diseases affect- 

 ing plants at the present time 

 must, therefore, be attributed in 

 part to lack of knowledge and lack 

 of skill in handling the crop. Diseases 

 may also be encouraged by extensive 

 modifications of the natural habits of 

 growth through breeding and cultiva- 

 tion and to the practice of increased 

 forcing. New parasitic organisms have 

 also been introduced from time to time 

 from other countries, through traflSe. 

 Some of these fungi, however, which 

 have recentl}' proven disastrous, have 

 been with us for some years, if not al- 

 n;iys, and one of the principal reasons 

 of their becoming more troublesome at 

 the present time can be attributed to the 

 increased production of more succulent, 

 tender plants, brought about by forcing, 

 which enables these parasites to find 

 more favorable conditions in which to 

 thrive. 



With every modification and innova- 

 tion in the growing of plants, there are 

 likelj' to occur new difficulties and ob- 

 stacles to be overcome. Constitutional 

 weaknesses, which develop in some varie- 

 ties and are inherited in others, are un- 

 favorable to immunity. Varieties of car- 

 nations inclined to succulency, or having 

 two or three per cent more water con- 

 tents in their leaves, have jiroven much 

 more susceptible to rust than those con- 

 taining less water. 



There is little doubt but that many 

 diseases could be prevented by modifi- 

 cations in the methods of growing plants, 

 if such could be adopted. The so-called 

 "drop" in lettuce would prove less dis- 

 astrous if the plants could be elevated 

 from the soil sufficiently to allow air and 



light to penetrate to the stem. This 

 Mould result in producing firmer and 

 more resistant tissues. Experiments 

 h;ive shown that a covering of coarse 

 s.-iod about lettuce plants materially re- 

 liuced rot, simply from the fact that 

 sand retains moisture much less readily 

 tlii.n loam, thus offering less favorable 

 opportunities for fungous infection, and 

 i:o doubt a circulation of air about the 

 stems would prove beneficial. In the 

 same manner, sub-irrigation reduces 

 stem-rot by maintaining a smaller 

 amount of moisture in the top layers of 

 soil. The shutting out of light and air 

 by planting too thickly constitutes a 

 source of danger to disease. Water cress 

 and parsley offer gopd examples of the 

 effects of over crowdipg, due to luxuriant 

 growth. When these -eipops are allowed to 

 grow high and become thick they pro- 

 duce weak stems, and develop stem-rot, 

 whereas being closely cropped there is 

 little loss from this disease. The ex- 

 elusion of light and air necessarily aris- 

 ing from an overcrowded condition are 

 responsible for this. 



In must instances the stem-rot of the 

 chrysanthemum has been induced by 

 over-crowding and undoubtedly the car- 

 nation would suffer less if more light 

 and air could reach the stems. Various 

 stem rots could undoubtedly be eliminat- 

 ed, to a large extent, by changing the 

 soil conditions about the plants, such 

 as by the application of coarse sand 

 around the stems. In one case the stem- 

 rot in the parsley was eliminated by set- 

 ting the plants well up above the soil, 

 thus exposing the stem and crown to 

 light and air, which resulted in the de- 

 velopment of more resistant tissues. 



The matter of moisture on the foliage 

 plays an important part in infection. 

 The carnation rust has been largely re- 

 duced by subirrigation methods and also 



