Inoculating Methods in Tobacco Mosaic Studies

Abstract

The most effective way of trans- ferring mosaic virus to tobacco plants is gentle rubbing over a large leaf surface with a cloth soaked in extract from mosaic plants. Scratches are much less effective, even when made i n the presence of the virus. The virus of tobacco mosaic does not readily enter wounds made in the leaves of healthy tobacco plants if these are made before its application. Entrance seems to be instantaneous upon the production of a suitable wound in the presence of the virus. Immediate removal of the excess of mosaic extract by washing does not decrease the total number of infections, but in some cases actually increases it.