58 CROP PRODUCTION 



planting of seed from fields free from the disease and 

 adequate rotation are the chief preventive measures. 

 The Powdery Mildew is often troublesome late in the 

 season and in rather moist climates. The methods of 

 preventing the Spot disease are also helpful for this. 



The most destructive insect enemies of Peas are the 

 Pea Aphis and the Pea Weevil. The Aphis, fortunately, 

 is only abundant during occasional years and ordinarily 

 is not troublesome. The Weevil is more regular in ap- 

 pearance. Its life-history is similar to that of the bean 

 weevil. If all the pea weevils present in a locality in 

 spring are destroyed by concerted action in fumigating 

 stored peas with carbon bisulphid, there will be little 

 trouble from the pest. 



