92 



it can fall into the hands of children or irresponsible persons. To pre- 

 pare the formalin solution, mix 8 fluid ounces of commercial formalin 

 (otherwise known as 40 per cent formic aldehyde) with 15 gallons of 

 water. 



To treat the potatoes with the corrosive sublimate solution, immerse 

 them for an hour and a half in the liquid and then spread out to dry. 

 Finally cut and plant in the usual manner. A large barrel is a con- 

 venient receptacle for the solution. The potatoes may be placed in a 

 coarse sack and suspended in the liquid, care being taken to wash the 

 tubers before dipping, provided they are very dirty. All treated tubers 

 should be planted in order to avoid danger from the poison upon them. 



It has been shown that the formalin is fully as effective against scab 

 as the corrosive sublimate solution, and as it is far less dangerous it 

 will probably come into more general use. In treating seed with this 

 preparation the whole potato should be soaked for two hours in the so- 

 lution already described. After soaking, the potatoes may be dried, 

 cut, and planted in the usual way, care being taken not to allow them 

 to become contaminated by coming in contact with bags, boxes, or 

 bins where scabby potatoes have been kept. In practice it is found 

 that 1 5 gallons of either of the foregoing solutions will be sufficient to 

 treat 20 to 25 bushels of potatoes,, taking ordinary precautions of course 

 not to waste too much of the fluid as each lot of tubers is dipped. 



Tip Burn, Leaf Burn, or Scald. 



This disease of the leaves occurs in many parts of the country and 

 is often confused with early blight The tips and edges of the leaves 

 turn brown and these discolored areas soon become hard and brittle. 



The burning or sc tiding may occur at any time and as a rule is the 

 result of unfavourable conditions surrounding the plant. Long-con- 

 tinued cloudy and damp weather f ollowed by several hot and bright 

 days is very apt to result in the burning of the foliage. This is es- 

 pecially the case on soils carrying a comparatively small percentage of 

 moisture. When the weather is cloudy and damp the tissues of the 

 potato become gorged with water and this has a tendency to weaken 

 them. If the sun appears bright and hot when the leaves are in this 

 condition, there is a rapid evaporation of the moisture stored up in their 

 cells. The evaporation may be faster than the supply furnished by the 

 roots, and if this continues for any length of time the weaker and more 

 tender parts first collapse, then die, and finally turn brown and dry up. 

 Tip burn may also occur as the result of protracted dry weather. 



TREATMENT. 



Little of a specific nature can be said on the treatment of this 

 trouble. Numerous factors are involved in the matter, so that only 

 general statements are possible. Every effort should be made to keep 

 the plants in good growing condition, for if they become checked 

 through lack of proper food or cultivation or both they are more apt 

 to burn. It is a fact that where the Bordeaux mixture is used for 

 other diseases burn is less apt to occur, and this furnishes another 

 instance of the remarkable properties of the fungicide. Briefly, there- 

 fore, the plants should be kept as vigorous as possible by good culti- 

 vation, plenty of available food, and the application of Bordeaux 

 mixture, as recommended for early blight. 



