1962 Volume 27 Issue 3 Pages 143-146
In the present paper, the authors report the results of study carried out for a four year period from 1954 to 1957, regarding the effects of tobacco/cucumber mosaic disease to the yield and the quality of tobacco, with special reference to the time of inoculation. The ordinary strain of cucumber mosaic virus (CMV-O) was used for virus inoculum.
The test plots were set out as follows:
Plot A Inoculation was made to tobacco plants in the seedbed 15 days before transplanting.
Plot B Inoculation was made on the day of transplanting.
Plot C Inoculation was made 15 days after transplanting.
Plot D Inoculation was made 30 days after transplanting.
Plot E Inoculation was made 45 days after transplanting.
When compared with the untreated check plot, the decreases in yield were 30% in Plot A, 55% in Plot B, 5% in Plot C, 36% in Plot D, and 20% in Plot E. The decreases in quality were 30%, 39%, 41%, 24%, and 0%, respectively. When these decreases are expressed in value per unit acreage, they were 51%, 71%, 74%, 51%, and 18%, respectively.
The damage in Plot A was about equal to that in Plot D, the damages in Plot B and Plot C were most severe, while the damage in Plot E was relatively small. It is assumed that the extent of the damage seems to depend on the rise and fall of the virus concentrations in the infected tobaccco and of the symptoms which followed the virus concentrations and at the same time on their relationship with the growth stage of tobacco. The losses in earnings caused by tobacco/cucumber mosaic disease are about equal to those caused by tobacco mosaic disease, but the former affects the yield rather than the quality of tobacco.
The damage by tobacco/cucumber mosaic disease may be estimated accurately in terms of the time of infection, if influences of the weather at the site are properly taken into account.