PESTS AND DISEASES OF PLANTS 237 



Root and Stem Rot. Causes a "damping-off" of seedlings. Also 

 attacks the tubers of potatoes, the subterranean parts of the tomatoes, 

 and the fruits touching the soil. Apply lime to aerate the soil. 

 Rotate crops. 



Dry Rot of Potatoes, Wilt of Tomatoes, Wilt of Egg-plant. All 

 of these diseases produce a wilt upon the host plants, affect the roots, 

 and may even cause a "damping-off" of seedlings. Treat seed with 

 formalin before planting. Keep weeds out of fields in winter. Rotate 

 crops, so as to have clean soil each year. 



Early Blight. A typical leaf-blight causing brown spots to appear 

 on the foliage. Affects potatoes, tomatoes and daturus. Spray with 

 Bordeaux when the plants are six inches high and repeat with three 

 applications two weeks apart. Treat seed with formalin before plant- 

 ing. Rotate crops. 



Potato Scab. Produces large rough blotches on the tubers. 

 This disease cannot be dealt with w i hile the plants are growing. Great 

 care must be exercised in the matter of seed selection. Treat all seed 

 of doubtful origin with corrosive sublimate. Rotate crops so as to 

 keep the soil fresh. 



Squash, Pumpkins, Cucumbers, Melons, Etc. 



Melon Aphis. Attacks all parts of the vines and is usually 

 accompanied by a black smut, which grows upon the honey-dew 

 secreted by the louse. Spray with kerosene emulsion or tobacco 

 washes. 



Green Lady Birds, Striped and 12-Spotted. The larvae and 

 adults of these beetles destroy flowers and foliage of the plants 

 and gnaw the rinds of the fruit. Methods of control are as follows: 



Repellants. Dust with tobacco dust or with naphthalene. Soak 

 lumps of gypsum in a mixture of kerosene and turpentine and place 

 them under infested vines. Insecticides Dust with lime and then 

 spray or dust with Paris green or arsenate of lead. 



Squash Bug. Hand pick early in the season; also pick off eggs 

 and destroy. Eggs are deposited in clusters on the leaves when the 

 vines are very young. Trap bugs by laying boards loosely on the 

 ground under which they crawl for protection. If very troublesome, 

 a repellent of gypsum saturated with kerosene scattered about the 

 grounds is effective. As soon as crop is harvested, gather and burn 

 vines. Do not allow weeds to grow on the ground during winter 

 months. 



Downy Mildew. Disease first appears in the center of the vine 

 and spreads outwardly. Spray with Bordeaux to which is added one 

 gallon of sulphurous acid to every 100 gallons of spraying material. 

 Repeat every ten days. 



Leaf Blight. Produces spots on the leaves which spread very 

 rapidly. This disease hastens ripening, injures production and de- 

 stroys the quality of the fruit. It particularly affects cantaloupes. 



