The Control of Insect Pests and Plant Diseases. 



607 



tins 254 and 266.) For use of insecticides in Bordeaux, see "steely-beetle." 

 (p. 478.) 



This is a fungous disease most evident on the leaves, making 



Downy large brown spots on upper surface with white downy growth 



mildew. beneath. It also attacks the green fruit, causing what is known 



to growers as "hard white berry." Bordeaux as applied for 



black-rot (page 492) will control this disease. 



LETTUCE. 



This is a fungous disease often destructive in greenhouses, dis- 

 Drop or rot. covered by the sudden wilting of the plants. It is completely 



controlled by steam sterilization of the soil to the depth of two 

 inches or more. If it is not feasible to sterilize the soil, use fresh soil for every 

 crop of lettuce. Massachusetts Bulletin 69. 



Downy 

 mildew. 



MUSKMELON. 



This is commonly called "blight" and is a very troublesome 

 disease. The leaves show angular, dead, brown spots, then' 

 dry up and die; the fruit often fails to ripen and lacks flavor. 

 The disease is caused by the same fungus 



as is the downy mildew of cucumbers. No effective m.ethod 



of control is known. While Bordeaux has proved efTective 



in controlling the downy mildew en cucumbers, it seems to 



be of little value in fighting the same disease on melons. 



Report of Botanist of Connecticut Station, 1904. 



This is same as the wilt of cucumbers; 

 same treatment is given. 



OATS. 



WUt. 



Smut. 



Fig. 215. 



The most common and destructive disease 

 of oats is smut, carried over from one 

 season to the next by the fungus spores 

 on the seed. It is entirely prevented by treating the seed 

 oats before planting with a solution of formalin, i pint 

 to 45 or 50 gallons of water. Place the oats on a clean floor 

 and sprinkle on the formalin as they are shoveled over. U.se 

 one gallon to the bushel. Mix the oats thoroughly, then 

 shovel them into a pile and cover with blankets or canvas. 

 After standing in the pile two to four hours the oats, if they 

 are to be drilled, should be spread out to dry; or they 

 may be sown by hand without drying. U.se one peck more 

 seed per acre to allow for swelling of the grain. Treat- 

 ment once in three years is usually sufficient to prevent 

 material loss from smut. U. S. Farmers' Bulletin 250 and 

 Wisconsin Bulletin iii. 



Fig. 215. Cai-:>»i:U. 



