200 THE CHIEF SOUTHERN AGRICULTURAL CROPS 



larvae. Baiting the field in advance of planting 

 with a poisoned bran mash is the best remedy for 

 these insects. It is best to sweeten the mash with 

 a little molasses, which will also make it more 

 adhesive. It should be scattered in the field at least 

 a week before planting. 



The well-known large green tobacco worm, which is 

 the larva of a Sphinx moth (^Protoparee)^ is a widely 

 destructive tobacco enemy. It may be controlled 

 either by hand picking or by dusting with Paris 

 green. In the tropics Paris green is also largely 

 used for insects of the climbing cutworm type. 



Several fungous leaf-spot diseases of tobacco are 

 known, but as a rule they are not seriously trouble- 

 some, and little attempt has been made to treat them. 

 Bordeaux mixture would be the natural remedy, but 

 its use is not permissible as it adheres so long that its 

 presence on the leaf would be objectionable. Bacte- 

 rial root rot of tobacco has appeared in certain local- 

 ities, but so far it has been rather local and as yet 

 no efficient remedy can be suggested. 



An obscure disease of tobacco that is not of para- 

 sitic origin occurs quite frequently and is widely 

 distributed. Tlie plant becomes somewhat dwarfed, 

 the leaves are wrinkled, and streaked and spotted 

 with yellow; it is known under various names, but 

 the term " mosaic disease " is the one usually applied, 

 on account of the peculiar coloring of the leaves. The 

 disease seems to be entirely functional and is due 

 to the improper secretion of some enzyme. This 

 trouble seems to be induced by anything which 

 strongly shocks the plant and suddenly interrupts its 



