1962 Volume 27 Issue 3 Pages 115-121
The effect of spraying with antiviral chemicals upon the systemic and local infections of plants by several viruses was investigated. When these chemicals were sprayed on TMV-inoculated tobacco plants or TMV plus PVX-inoculated tomato plants 5 or 7 times before and after the inoculation, no decrease in percentage of disease development was found, although the incubation period was somewhat prolonged and the virus content of infected plants, determined b the method of Bancroft and Curtis, was diminished by application of Actidione (2ppm), Dextromycin (100ppm), and Mitomycin (50ppm) about 10∼50 per cent below that of controls. In the case of CMV-inoculated tomato plants, number of infected plants was less by the spraying with Actidione, Dextromycin, and thiouracil.
The formation of local lesions produced by the following virus-host combinations, such as TMV-bean, TMV-Nicotiana glutinosa, and PVX-Capsicum annuum, was markedly inhibited by the treatment with Actidone and thiouracil on leaf surface. The rice dwarf disease which is transmitted by the leaf hopper, Nephotettix cincticeps, was unable to be prevented by the spraying. However, the incubation period of this virus prolonged 2 or 3 days by thiouracil or Actidione-spraying. By the soil treatment with thiouracil (100ppm), the occurrence of necrotic disease of tomato plants, which is caused by the combined inoculation with TMV and PVX, was diminished to some extent.
From these results, it is concluded that the antiviral substances may be applicable to some virus diseases if proper time and method of application are investigated.