DISEASES OF CULTIVATED PLANTS 619 



ing the water at 110 degrees to 120 degrees. Lift it, and when it 

 has drained a moment plunge it into the vessel with water at 133 

 degrees. After a moment lift it, allowing most of the water to drain 

 out. Then replunge it, and repeat several times, making sure every 

 grain is wet with the hot water. If the water is maintained at a 

 temperature of 133 degrees the seed may remain in the bath ten 

 minutes, which will kill the spores without injuring the seed. 

 Should the temperature rise to 135 degrees the seed should not be 

 kept in the water over five minutes. 



The nearer the temperature is kept to 133 degrees Fahrenheit 

 the better will be the results. Below this the spores are not so likely 

 to be killed. Above 135 degrees the seeds may be injured, unless 

 the immersion is very brief. The gauging of temperature should 

 be done with a reliable thermometer. The sack or wire basket 

 should be amply large so that seed while being treated may move 

 above. 



If a quantity of seed is to be treated two persons should be on 

 hand, one to handle the grain, the other to maintain the proper 

 temperature of the water, by adding hot or cold water from time to 

 time as may be necessary. That the temperature may be uniform 

 the water should always be stirred ' whenever hot or cold water is 

 added. If steam is available a small pipe running into the hot water 

 vessel will make it comparatively easy to maintain the proper tem- 

 perature. 



After treatment seed should be spread out on a clean floor in an 

 airy place in a layer not thicker than three inches, or it may be 

 placed upon sheets resting on a lattice frame a foot or so above the 

 ground. To facilitate drying, grain spread out upon the floor 

 should be shoveled over two or three times a day. If thoroughly 

 dried, seed may be treated some months in advance of sowing. If 

 to be sown immediately they need not be so thoroughly dried. 



After treatment care will be needed to avoid reinfection. The 

 seed should not be placed in any vessel or on any surface likely to 

 contain spores of smut, or where smutted grain has been before. 

 Tools or vessels likely to have spores on them may be disinfected by 

 dipping them in scalding water. The floor where the rice is to be 

 spread may be previously disinfected by washing with a strong solu- 

 tion of copper sulphate. 



Other Treatments. Formalin (a 40 per cent, solution in 

 water of formaldehyde gas) has been found to be an effective rem- 

 edy for smuts. It is used at the rate of 1 part to 50 or 60 gallons of 

 water. The seed should be soaked in this solution two hours and 

 otherwise managed as in previous treatments. The dilute solution 

 is not poisonous. The material should be purchased full strength. 



Copper sulphate (blue stone) 1 pound in 24 gallons of water is 

 effective as a treatment for smut. The grain should be soaked in 

 this solution 12 hours, after which it should be soaked in lime water 

 for 5 minutes. It should then be drained and dried as in other 

 treatments. The lime water is to be made by slacking 1 pound of 



