SWEET PEA DISEASES AND THEIR CONTROL. 

 By J. J. Taubenhaus, Ph.D., College Station, Texas. 



Presented for Publication, March 25, 1916. 



The John Lewis Russell Lecture. 



Many of us still remember the day when the hollyhock was 

 a favorite flower, both in England and in this country. The holly- 

 hock, however, has had its day. Accustomed, as we were, to 

 giving it the place of honor in our gardens, it is now neglected and 

 is hardly being considered as an ornamental flower. This change 

 of attitude was painfully and not willingly adopted by growers. 

 Numerous diseases especially the rust {Puccinia malvaceaerum 

 Mont.) have practically made it impossible to grow this once orna- 

 mental plant. The sweet pea is now undergoing similar critical 

 conditions. Numerous diseases are threatening its existence as a 

 cut flower of economic importance. In England, growers are 

 very much discouraged because of these diseases. In the United 

 States, where this flower is gaining in popularity, conditions are 

 not different. 



There are few florists today who do not attempt to grow sweet 

 peas. The majority start with enthusiasm and hope of success. 

 However, many meet with reverses and give up in despair. On an 

 average, all growers start right as far as cultural requirements are 

 concerned. Why is it that so many fail? Failures with sweet 

 peas are not mere accidents. They are due in most part to specific 

 diseases caused by definite parasites. These diseases either so 

 weaken the plants as to render them unfit for production or else 

 kill them outright. Ninety percent of failure with greenhouse 

 sweet peas, especially, may be directly accounted to sick soils, 

 i. e. to parasitic fungi present there which make plant growth im- 

 possible. 



