668 INSECTS AFFECTING VEGETATION 



Copper Sulphate or Blue Stone. a. Dissolve one pound copper 

 sulphate in 5 gal. water by hanging a sack containing it in the 

 top of a barrel or tub until the sulphate is all dissolved. Dip the 

 grain in this solution for two or three hours and then spread out 

 to dry. 



b. A safer method. Dissolve one pound copper sulphate in 

 20 gal. water and let grain soak 12 hours. Then dip in solution 

 of one pound lime to 10 gal. water for five or ten minutes and 

 spread out to dry. 



Potassium Sulphide for Oats. a. Dissolve 2 pounds potas- 

 sium sulphide in 20 gal. water and soak seed 10 or 12 hours. 

 Then dry so the oats can be planted with drill or otherwise. 



b. Dissolve 1 pound potassium sulphide in 20 gal. water 

 and soak the oats 24 hours, and dry. This is an excellent method. 



Formalin for Wheat or Oats. a. Pile the grain on a floor 

 where it can be shoveled over or stirred. Mix one pound of For- 

 malin (Formaldehyde) in 50 gal. water and sprinkle over the 

 grain with a hand or garden sprinkler, stirring the grain until it 

 is all wet. 



b. Mix one pound of formalin with 100 gal. water and dip 

 the grain in it until it is thoroughly saturated. Spread out to 

 dry or plant at once. Formalin must be used with great care 

 for if used in too strong solution or the grain left in too long it 

 will destroy its germinating power. 



General Caution. In our experiments we have found that the 

 germinating power of seed wheat or oats raised at high altitudes is 

 quite easily injured. In treating it more than ordinary oare must 

 be taken. In using above methods with grain raised above 6,500 

 feet altitude, be sure that the water does not get too hot, and do 

 not soak more than eight or ten minutes. With other treatments 

 use the weaker solutions, and do not soak the seed more than 

 twelve to twenty hours. (Wyo. Press Bui. 15.) 



THE LIMITS IN SEED TREATMENT. 



It will be apparent that serious limits hold in regard to seed 

 treatments. Where the spores are external and simply adhering to 

 the seed grain, treatment will destroy these spores if rightly adapted 

 to the seed in question and the germination need not be much, if any 

 impaired. On the other hand where the seed infection is internal 

 rather than external, grave doubts arise as to the possibility of suc- 

 cessful seed treatment. It has not been found possible in the cases 

 of seed peas when infected with the blight fungus, or of seed wheat, 

 rye, etc., infected with the scab and other fungi to apply any seed 

 treatment which would destroy the infecting fungus without destroy- 

 ing the vitality of the seed grain. In general we may say that where 

 the seed infection or fungus spores, etc., are external to the visible 

 or germinable grain, seed disinfection through treatment is possible, 

 but for the internal fungi it is rarely possible. The loose smut of 

 wheat may be amenable to special seed treatment with only partial 

 loss of vitality in the seed wheat. (Ohio E. S. B. 214.) 



