CARNATION WILT DISEASES 



49 



Most of the New England carnation growers have conducted limited demonstra- 

 tions with chlorpicrin. Portions of the greenhouse beds were injected with 

 chlorpicrin at the rate of 2 cc. per square foot, well in advance of benching out- 

 side-grown plants. In most cases differences in favor of the treated soil were not 

 apparent, but in some cases the differences have been rather striking. Charles 

 Rice of Lexington obtained differences in the yield of carnations on old and new 

 soil treated with chlorpicrin applied in June before planting from the field, and 

 contrasts undoubtedly could have been shown in many of the other demonstra- 

 tions if the results had been measured in a similar manner, or if the ideal soil 

 conditions necessary to the efficiency of the treatment had existed at the time of 

 application. Some of these are (1) a loose permeable soil, (2) a relatively dry 

 soil holding only enough moisture to partially hold its shape when squeezed in 

 the hand, (3) a soil temperature warmer than 65° P., and (4) a seal of moist soil 

 on the surface, or a cover of paper or burlap for a few days after application, to 

 confine the gas. 



The bench plots in the Rice experiments comprised 65 square feet each. The 

 yield of flowers was recorded throughout the year. The gain of flowers indicated 

 in Table 16 represents the difference between the production on new untreated 



Table 16. Aver.\ge Yield of Carnation Flowers Per Square Foot. 



Old and New Bench Soil Treated With Chlorpicrin. 



Charles Rice, Lexington. 



1-0 New Soil, first year of use. not treated 



1-1 New Soil, first year of use, first treatment with chlorpicrin 



2-0 Old Soil, second year of use, not treated 



2-2 Old Soil, second year of use, second treatment with chlorpicrin 



3-2 Old Soil, third year of use, second treatment with chlorpicrin 



3-3 Old Soil, third year of use, third treatment with chlorpicrin 



4-3 Old Soil, fourth year of use, third treatment with chlorpicrin 



*Difference between the yield of flowers from untreated soil the second year of use and the 

 average of the yields from the treated plots. The 2-0 plot did not begin to produce flowers until 

 November; hence the November to May production of the other plots is given for comparison. 



