90 



beetle, the flea beetle, and other insects. Before adding the Paris 

 green it should be mixed with a small quantity of water, and when a 

 thin paste is obtained this should be thoroughly stirred into the barrel 

 of Bordeaux solution. 



The success attending the application of the Bordeaux mixture de- 

 pends in large measure upon the thoroughness with which it is applied. 

 To reach all parts of the plants above ground with a fine spray re- 

 quiries a good force pump and a suitable nozzle. The knapsack sprayer 

 will be found one of the most useful machines for spraying fields of 3 

 acres or less. For larger plantations more powerful machines should be 

 used. A cheap and serviceable apparatus, well suited for this work, may 

 be made by mounting a good, strong force pump on a barrel, and then 

 placing the barrel and mounted pump in a light wagon. The entire 

 outfit, including barrel, pump, hose, nozzles, operator, and boy to drive, 

 may be drawn by one horse. As the wagon is drawn slowly between 

 the rows the man in the wagon may operate the pump and at the same 

 time keep the mixture stirred, while two others on the ground hold 

 the nozzles and direct the spray over the plants. The nozzle found to 

 be the best suited to the work^is the Yermorel. This is now offered 

 for sale by pump manufacturers and dealers in seeds and agricultural 

 implements. W here there are only a few plants to treat, simple devi- 

 ces for the application of the fungicide, such as watering cans, the 

 syringes used by florists, etc., may be used. 



Potato Blight, Late Blight, or Pot. 

 (Phytophthora infestans (Mont.) de Bary.) 

 This disease attacks the leaves, stems and tubers. Generally the 

 first noticable effect upon the leaves is the sudden appearance of 

 brownish or blackish areas, which soon become soft and foul smelling. 

 So sudden is the appearance of the disease in some cases, that fields 

 which one day look green and healthy may within the next day or two 

 become blackened as though swept by fire. The rapid spread of the 

 disease, which is caused by a parasitic fungus, is dependent in large 

 measure upon certain conditions of moisture and heat A daily mean 

 or normal temperature of from 72° to 74° F. for any considerable time, 

 accompanied by moist weather, furnishes the best conditions for the 

 spread of the parasite. On the other hand, if the daily mean or nor- 

 mal temperature exceeds 77° for a few days, the development of the 

 disease is checked. This fact explains why the fungus seldom occur s- 

 to any serious extent in sections where the mean or normal daily tempera - 

 ture exceeds 77° for any length of time, and probably why it appears 

 later than the disease discussed under the former heading. The 

 tubers affected with the disease show depressed, dark-coloured areas 

 on the surface, while within are blotches and streaks of a brownish or 

 blackish colour. Other diseases may produce similar effects, so that 

 in this case the changes are nut so characteristic as those shown by 

 the leaves. For many years it was believed that most of the injury 

 to the potato was due to this disease, but recent investigations have 

 shown that view to be erroneous. 



TREATMENT. 



The same treatment as recommended for early blight should be fol- 

 lowed here, and will be found to prevent the blighting of the tops and 



