Potato. 351 



contact with the disease. It is safer to treat the seed before it 

 is cut; and if care is taken not to transfer the organism to the 

 cleaned potatoes, no scab should develop upon clean land. Hal- 

 sted has been successful in preventing the development of the 

 disease by rolling the seed in sulphur. He used the sulphur at 

 the rate of three hundred pounds to the acre, that which did 

 not adhere to the potatoes being sprinkled in the open row. 



IXSECT ENEMIES. 



Colorado Potato-beetle ; Potato-bug ( Doryphora 10-lineata, Say). 



Description. This insect is too well known to require a de- 

 tailed description. It hibernates during the winter as a mature 

 insect, and in the spring it begins to feed upon the foliage of 

 eggplants or potatoes as soon as these are at hand. The eggs 

 are laid on the under side of the leaves. They are bright yel- 

 low in color, and easily seen. The larvae appear in about a 

 week, and the plant is soon stripped of its foliage. In a short 

 time the grubs become full grown ; they then leave the plant 

 and pupate in the surface soil. Here they remain about ten 

 days, when the mature insect again appears. There are three 

 or four broods each year. 



Treatment. Potato-beetles are easily destroyed by spraying 

 the young plants with an arsenical poison. This should be 

 done early in the season so that the first beetles, or at least 

 the first brood of larvae, may be exterminated. The poison 

 should be made about one-fourth or one-third stronger than 

 for fruits, as these insects seem to require more poison than 

 most others. There is no danger of injuring potato foliage in 

 this manner. 



Flea-beetle (Phyllolreta vittata, Fabr.; Haltica striolata, Harris). 



Description. This species of flea-beetle, as well as several 

 others, makes the growing of many garden plants a difficult 

 matter. The mature beetles are, as a rule, not more than one- 

 tenth of an inch in length. They are very active, and move so 

 quickly that their popular name is very appropriate. The 

 beetles appear early in spring and eat out little cavities in the 

 tender foliage of young plants, often to such an extent that the 

 plants are ruined. If the work of the beetles does not destroy 

 the crop, the injured parts afford conditions suitable to the 

 growth of certain fungi, and these two parasites may succeed 



