16 



The Florists^ Review ^^^^ i i»i6. 



COLOR CLASSIFICATION. 



The American Peony Society is to 

 hold its thirteenth annual exhibition at 

 the American Museum of Natural His- 

 tory in New York, opening June 9. 

 Competition is not restricted to mem- 

 bers of the society and many trade 

 growers are expected to set up vases 

 of their best blooms in one or another 

 of the fourteen classes open to com- 

 mercial people. The amateur interests 

 are being specially well looked after 

 this time. 



The society announces: "There al- 

 ways is some uncertainty about color 

 classification in peonies. For instance, 

 the variety Baroness Schroeder is some- 

 times entered as flesh-pink, sometimes 

 as white. The understanding in the 

 Peony Society is now that in cases 

 where there may fairly be a difference 

 of opinion, an exhibitor shall not be dis- 

 qualified on the ground of misclassiflca- 

 tion." 



THE BOTRYTIS STEM-HOT. 



Can you tell me the cause of the stem- 

 rot on the peony plants that I am send- 

 ing with this letter? For two years a 

 few plants have been affected in this 

 manner, beginning to rot just above 

 the roots, finally drying up and drop- 

 ping off while the tops still seem to be 

 healthy. What can be done to prevent 

 this? C. H. H,— Me. 



An examination of the specimens 

 shows that they are affected with the 

 botrytis stem-rot, one of the commonest 

 and most destructive diseases of the 

 peony. H. H. Whetzel, collaborator in 

 plant-disease survey in the U. S. Depart- 

 ment of Agriculture, stationed at Cor- 

 nell University, Ithaca, N. Y., where the 

 American Peony Society has its test 

 grounds, has made an exhaustive study 

 of the stem-rot disease of the peony, the 

 results of which were incorporated in an 

 address before the Massachusetts Horti- 

 cultural Society, from which the fol- 

 lowing is quoted: 



"The botrytis blight is by far the 

 most common and destructive disease 

 of the peony so far as known at pres- 

 ent. This disease is frequently epi- 

 demic, especially during wet springs. It 

 occurs wherever peonies are grown, ap- 

 parently the world over. It is well 

 known in Europe, especially in Holland 

 and England. Much in the way of scat- 

 tered notes and records of its occur- 

 rence have appeared in florists' papers 

 and experiment station reports for the 

 last twenty years. I published a short 

 article on the symptoms and destruc- 

 tiveness of this disease in the trade 

 press in September, 1912. 



"The disease affects stems, buds and 

 leaves, appearing on these organs in the 

 spring and summer in the order given. 

 The first appearance of the malady is 

 almost always early in the, spring, as 

 the stalks are coming up. Shoots four 

 to eight inches tall, their leaves not yet 

 expanded, will suddenly wilt and fall 

 over. Examination shows them to be 

 rotted at the base or below the surface 

 of the soil. The lesions begin usually 

 at the base of the first leaf sheath and 

 spread down to the crown and up often 

 an inch or more above ground. The 

 rotted portion soon becomes covered 

 with a felty brown coat of Spores and 

 spore stalks of the fungus, thus distin- 

 guishing it from the similar stem-rot 

 caused by sclerotinia. While it is gen- 

 erally the young stems that are affected, 

 I have seen stalks with blossoms open- 

 ing, suddenly wilt and fall over from 

 botrvtis stem-rot at the base. 



' ' The cause of thjp disease has long 

 been attributed to tft fungus, botrytis 

 found constantly aapociated with the 

 lesions on styem, bu^and lead. There 

 are many described species of botrytis 

 some of which are common on green- 

 house and garden crops. The botrytis 

 forms found on peonies have been re- 

 ferred usually to Botrytis vulgaris, or 

 Botrytis cinerea, and Botrytis pseonite 

 the last described by a Hollander as 

 the cause of the disease in that country. 



"My own studies indicate that there 

 are at least two distinct species of bo- 

 trytis attacking and causing identical 

 symptoms in the peonies, both in this 

 country and in Europe. The species, 

 while quite distinct in structure, are 

 similar in their life habits and effects 

 on the peony. One forms large sclerotia 

 (resting bodies), while the other forms 

 minute ones. I have never seen the 

 sclerotia of the large form except in 

 my cultures, but the small ones are com- 

 monly formed in the diseased stalks 

 just beneath the epidermis and appear 

 as black pimples the size of a pinhead. 

 Presumably they serve to carry the 

 fungus through the winter on the old 

 stubble left by cutting away the tops. 

 There in the spring they probably give 

 rise to a new crop of spores, in just 

 the best position to infect the new 

 shoots when they come up. I have not 

 yet determined whether these pathogens 

 ever attack crowns and roots or not. 



"Eradication measures offer the most 

 promise of success in the control of the 

 botrytis blight. To be effective, how- 

 ever, they must begin with the care- 

 ful removal of the old stubs in the 

 autumn or early in the spring and be 

 prosecuted persistently throughout the 



W. S. Veils, Secretary Missouri State Florists* Associatioo. 



