PLANT DISEASES 117 



Poisoned Bait. — Poisoned bait is very effective against 

 certain kinds of insects, namely, the cutworms. Poisoned 

 bait is made by dipping freshly cut clover into a strong 

 mixture of Paris green and water or by making a stiff mash, 

 composed of 6 pounds of bran to which about \ pound of 

 Paris green or white arsenic is added. Use only enough 

 water to hold the bran together. A small quantity of sugar 

 or molasses is added to make it sweet. The bait is then 

 placed in small piles which are scattered around the area to be 

 planted. The best results will be secured if the baiting is 

 done a few days before the time of planting. 



PLANT DISEASES. 



The diseases that affect the cultivated plants may be 

 arbitrarily divided into : fungous diseases, bacterial diseases, 

 and physiological troubles. 



As we go more deeply into the nature of the changes which 

 take place in the plant which are brought about by disease, 

 it is necessary to distinguish between the different kinds. 

 A plant may be diseased as a whole, because all or practically 

 all of its tissue is in a diseased condition, such as occurs 

 when a fungous or a parasitic plant invades all parts of the 

 host. Again, a plant may die throughout, because some 

 organ which is essential to its life is seriously affected, as for 

 example when the roots rot, due to the presence of some 

 parasite which hinders the supply of plant food. In a large 

 number of cases we find the disease to be purely local and 

 never extending into the rest of the tissue beyond that which 

 is affected, and which only causes death to the affected part. 

 Symptoms of Disease. — Many amateurs and all experienced 

 growers know that certain symptoms are present in the sick 

 plant as well as in the sick animal. The symptoms in a sick 

 plant vary according to the kind of disease. Many symp- 

 toms are often present which indicate that the plant is not 

 in a healthy condition, and it should be attended to at once, 

 but further diagnosis is difficult. 



Generally speaking, a common symptom in a physiological 

 trouble is the yellowing of the leaves accompanied by wilting 



