Letters on the Diseases of Tlants. 



45 



appropriate closing statement to this section than that of the general 

 principle that whatever moves and comes into contact with the eggs and 

 larvse of gall-worms is likely to afford them the means of finding new victims. 

 In addition to the foregoing, I would caution agriculturists, seedsmen, and 

 nurserymen against rearing, buying, or selling trees, plants, or tubers which 

 show any swelling on the roots, except such as are loell knoion to be natural 

 to them. 1 know of a case where this worm was introduced in seed potatoes, 

 and I am confident that this is one of the common ways that this pest travels 

 e7i masse from one district to another. Picture some poor fellow struggling 

 to make for himself and a family a living out of the land. Deciding to try 

 potatoes, he unknowingly secures a lot of seed infested with the gall-worm. 

 Bear in mind that it is not uncommon for a potato to contain more than ten 



Fig. 55. — A potato deformed by gall-wuiiiis. All the uiuuerous lumps on the siu-face of the 

 potato are caused by the gall-worms. This potato contained on a moderate estimate 

 at least 10,000 eggs and worms. 



thousand worms. Look at this ugly specimen ! Every knob on its surface 

 contains hundreds of worms ! These he unsuspectingly plants, and (woe is 

 he !) his land is permanently infested. After that, almost any crop he may 

 try to raise will be more or less handicapped, and possibly ruined, as I have 

 seen, and others can testify. Closely scrutinise the roots of all the plants or 

 trees you buy, and unhesitatingly refuse any that shoio galls. 



