EXPERIMENT STATION BULLETINS. 



531 



SPRAYING. 



The value of bordeaux mixture as a repellant for leaf hoppers and 

 other insects, has been demonstrated during this past season, 1921. It 

 requires, however, that the spray be applied with a high pressure outfit 

 and with sufficient nozzles to completely cover the tops and bottoms of 

 leaves and the whole plant. This spraying must be started when the 

 potato stalks are from three to six inches high, and continued until the 



Fig. 21. An effective spray outfit for disease and insect control. 



creases the yield per acre of potatoes. 



Proper spraying in- 



potatoes have reached maturity. Late fall spraying this year con- 

 trolled early blight which in many instances, especially with the rurals, 

 came and finished up the work of the leaf hoppers. Slight injury is 

 done to the plants by these late sprayings, even though the wheels of 

 the sprayer do run over many of the tops. The loss is not comparable 

 to the loss that would occur if the spraying was not done. By adding 

 arsenicals in the early sprays, the potato bugs, etc., can be kept down. 

 High pressure sprays are however, very essential to complete control, 

 sprayers capable of maintaining 150 to 200 lbs. pressure are none too 

 good especially for the careful grower of certified seed f)otatoes. For 

 detailed information relative to spraying potatoes, write to the Director, 

 Michigan Agricultural Experiment Station, East Lansing, Michigan. 



Hand sprayers or knapsack sprayers do very well for controlling 

 potato bugs and such other insects as affect the potatoes by eating the 

 foliage. When bordeaux is applied with these small sprayers it pro- 

 tects the plants to some degree, and makes for a stronger, healthier 

 plant, and is considerably better than no spray at all but is of little 

 value against the leaf hopper or blight disease when they occur in a 

 serious manner. This type of sprayer is adapted to the small farm or 

 garden spot. 



