Ragged margins and nar- 

 row, swordlike leaves mean 

 frenched tobacco. It is pos- 

 sible that one frenched 

 plant in a field ma/ be 

 enough to raise the suspi- 

 cions of prospective buyers, 

 and the price of healthy 

 plants is lowered. 



By LINUS H. JONES* 



FRENCHING" is a word 

 spoken in low tones, hardly 

 above a whisper, among tobacco 

 growers who try to keep this un- 

 known plague well hidden from the 

 public. Why does the word "french- 

 ing" provoke such fear and create 

 a state of unrest among tobacco 

 men? One look at the picture on 

 this page and you will have the 

 answer. Crop loss and a poor price 

 at harvesttime. 



Frenching — A Peculiar Disease 



The frenching of tobacco is a 

 peculiar disease that stunts the plant 

 and causes it to produce a profu- 

 sion of worthless, very narrow 

 leaves, more or less yellow in color. 

 Sucker growth is stimulated to de- 

 velop in every leaf axil. Even the 

 internal structure of the leaves is 

 quite abnormal because the cells are 



* Assistant Research Professor, Botany 



prevented from organizing proper 

 tissue formation and development. 



No Disease Organism Found 



According to past records, french- 

 ing has been recognized in the 

 United States since 1688 and in 

 Europe since 1857. It is now known 

 to be world-wide in occurrence. No 

 disease organism has ever been 

 found in the plant to indicate that 

 the disease is due to bacteria or 

 fungi, and neither has it been 

 possible to classify the malady as of 

 virus origin. 



Not until it was demonstrated 

 that frenching could be induced or 

 dispelled at will by altering the soil 

 temperature had it been possible to 

 subject the problem to a thorough 

 laboratory investigation. Through 

 this soil temperature technique many 

 facts have been added to our store 

 of knowledge, which may lead to a 

 solution of this complex problem. 



