No. 6. DEPARTMENT OF AGRICULTURE. 74i 



The fields under cultivaHon the year the beetles appear escape much 

 infestation bv grubs, and sod hmd broken the next spring, when the 

 grubs are small, may be cultivated in corn without much danger. 

 Winter jjlowing is reconunended, and has a degree of effectiveness 

 in a cold winter. Cold, hea^y rains, during the month the beetles 

 should appear cause the death of many. 



The right thing to do in respect to white grubs is to watch for them 

 at time of plowing the ground, and if they abound, the potato crop 

 should be omitted. If planting is done, early varieties should be 

 used, and the crop should be dug as soon as it is ready for market- 

 ing. It is idle to plant a crop like potatoes to be eaten by insects 

 we can not fight effectively, and the white grub belongs to his class. 



FUNGOUS DISEASES AND EEMEDIES. 



Probably the most serious fungous diseases of the potato are 

 classified as blights. Throughout the potato belt of this country, 

 but chiefly in the southern half of the main belt, the Early Blight 

 {Maa'ospornim solani) is restricting yields enormously. In the north- 

 ern half of the belt, and farther south in cold, wet seasons, the Late 

 Blight ( Phytophthora infestans) has caused great loss. Much con- 

 fusion exists in the minds of many growers concerning the character 

 of these blights. The Cornell Station has had unusual success in 

 control of the blights by spraying with the Bordeaux mixture. I 

 incorporate in this treatise its descriptions of Early Blight and Late 

 Blight, and an account of the method employed at Cornell in making 

 the Bordeaux mixture, reserving the privilege of some comment on 

 one or two points in which my own experience in spraying does not 

 accord fully with that of the Station. The quotations are made 

 from Bulletin No. 140, and areas follows: 



"Early Blight. — As the name indicates, this usually makes its ap- 

 pearance early in the season and upon early varieties of potatoes. 

 Hot, dry weather favors its growth, and it is usually most severe in 

 its attacks where the potatoes are planted on dry soils. It will, 

 however, make its appearance when the weather is modterately cool. 

 Whenever the potato foliage has been injured by the flea-beetles 

 it seems to be predisposed to attacks of the early blight, the spores 

 finding a favorable resting spot on the injured places of the leaf. 

 Any condition or treatment which has produced a weakening of the 

 plant causes it to be more likely to attacks of blight. Strong, 

 healthy growing plants may be entirely free from attack, while plants 

 which have for any reason been checked in their growth fall an easy 

 prey to the disease. While this early blight does not cause the po- 

 45 



