ORNAMENTAL PLANTS 



The ornamentals give rise to problems unique in the field 

 of plant pathology due to the fact that the number of species 

 of plants involved is much larger than with any other group 

 of crop plants, and moreover, because they vary greatly in 

 value; some of them, as for example the rare orchids, have a 

 market value higher than that of any other individual culti- 

 vated plant; other ornamentals are of negligible commercial 

 value. There is large diversity of financial interest; some 

 crops are grown on a large scale by only a few individuals, 

 others to considerable extent by nurserjmien and seedmen, 

 other crops are rarities in only a few greenhouses, while to 

 many the flower garden in the yard has a high sentimental, 

 though small money, value. Aside from a few standard 

 flowers, as for example roses, violets, chrysanthemums, 

 carnations, etc., and certain nursery stock, so few individuals 

 are interested, or have so small a financial risk in these crops 

 that large expenditures of public funds have not been made 

 for investigation or control of the diseases. The result is 

 that aside from the standard ornamental crops and a few 

 isolated cases of other crops, the diseases have received no 

 such complete study as has been given for example to diseases 

 of other plants of general interest and large commercial 

 value. Indeed in many cases knowledge is limited to a mere 

 note of the occurrence of certain diseases or parasites, and the 

 course of procedure is only to ])e inferred from knowledge of 

 similar diseases. Flower fanciers and the conunercial growers 

 of ornamentals are able and willing and can well afford to use 

 the best methods of treatment, and it is unfortunate that so 

 much is lacking here concerning treatment for the specific 

 diseases. 



406 



