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MASS. EXPERIMENT STATION BULLETIN 246 



Fig. 2. 



Type of duster and method of operation recommended for applying sulfur 

 dust to greenhouse cucumbers. 



forward with one hand while the other holds the handle supporting the duster. 



Quiet air should prevail in the greenhouse to permit the dust to settle. 

 This is obtained by closing all ventilators for 30 to 45 minutes previous to 

 dusting. If closing is likely to cause unfavorable growing temperatures, dust- 

 ing should be done in the evening or morning wlien the ventilators may be 

 closed for longer periods thus allowing a more complete settling of the dust. 



When dusting, the course of travel should aepend on the construction of 

 the greenhouse. In houses 40 feet wide with walks through the center and 

 around the sides, all of the dusting should be done from the walks (Fig. 3,a) ; 

 in houses wider than 25 feet and provided only with central walk, every 3 

 to 5 rows should be entered for about one-half the distance (Fig. 3,b). If 

 only outside walks are present the course of travel should be between every 



