1916] PARASITIC RHIZOCTONIAS IN AMERICA 319 



While the cause of the disease was not known at that time, from 

 the description of the symptoms it is not to be doubted that it was due 

 to Rhizoctonia. 



A great loss of plants from stem rot occurred thruout the country 

 about 1900. Below are given a few excerpts from notes on this dis- 

 ease which have appeared during the last thirty years, some of which 

 agree with our present-day ideas: 



1886. "Deep planting causes the disease in many houses. " 



"In our opinion high temperature and deep planting have much to do with 

 the disease. ' ' 



1898. ' ' The most dangerous disease that attacks the carnation. Some varie- 

 ties appear more subject to this disease than others, and there is considerable 

 complaint about Flora Hill and Silver Spray this season. The most common 

 error that very often leads to this disease is too deep planting. The plants should 

 never be planted deeper than they stood in the field, preferably not so deep. The 

 stem of the plant should be out of the ground sufficiently to hold the branches 

 away from the soil. I believe this disease is not found on carnations alone, but 

 on other plants too, and the spores of this fungus may have been embedded in the 

 soil, carried over or imprisoned, dormant in the plant from the cutting bench. 



' ' To check and prevent the spreading of this disease, dust flour of sulfur 

 over the plants, and shake them so it will lodge on the stem and branches and on 

 the soil around the stem. ' ' 



1900. "Climatic conditions rather than anything else are the chief causes of 

 the trouble. High ranges of temperature whether in the cutting bench, field, or 

 house, the results are the same, the amount of rot varying with preceding condi- 

 tions. Thus, after heavy rains inducing soft growth, a rise of temperature into 

 the 90 's is a capital condition for the development of stem rot. Some varieties 

 are also more susceptible to attacks than others, the woodier ones being able to 

 withstand it more than those of soft growth." 



1904. ' l Stem rot is due to allowing plants to become pot-bound. 



"Rich soil with too much manure causing a rapid growth causes stem rot. 

 I believe this to be responsible for more stem rot than all other conditions com- 

 bined. Too deep planting also favorable for stem rot. Water when absolutely 

 necessary and then water thoroly. ' ' 



1906. "Presence of wounds on the bark, or punctures made by insects; 

 faulty planting; sour or too highly enriched soil; lack of drainage; careless cul- 

 tivation; lack of fresh circulating air; the maintenance of too great heat com- 

 bined with atmosphere heavily charged with stagnant moisture during the time 

 when the outdoor stocks are housed, will cause stem rot to become severe in the 

 benches. ' ' 



1907. "Stem rot is the most dreaded and only disease of carnations in the 

 South. ' ' 



1909. "Stem rot more dreaded in South than in North." 



1911. "Fresh air, plenty of circulation, a sweet soil, and proper watering 

 will avoid to a great extent the appearance of stem rot or stop its spread. Weather 

 conditions seem to play an important part, and in most cases as soon as cold 

 nights are the rule, our troubles grow less. The greatest benefit is derived thru 

 a clear and rather dry atmosphere. Deep planting not so important. Too much 

 manure not necessarily a cause of stem rot. 



"Stem rot is more prevalent in sour soils than others. The surface of the 

 soil should be kept open by frequent scratching. A dry interior and a wet surface 

 is very conducive to stem rot." 



1913. "Stem rot in the South is more serious than in the North." 



The following older carnation varieties have beeen reported as being 

 especially susceptible to stem rot : La Purite, Crimson King, De Graws, 

 Sewan. Flora Hill, Silver Spray, McGowan, Portias, Scott, Jubilee, 



