b BULLETINS OF THE BUREAU OF PLANT INDUSTRY. 



Bulletin No. 181. — The Curly-Top of Beets. Page. 



Introduction 9 



Symptoms of curly-top 9 



External symptoms 9 



Internal symptoms 11 



Symptoms in seed beets 12 



Only one symptom really characteristic 13 



Cause of the disease 13 



Theories 13 



Preliminary experiments 13 



Isolation cages 14 



Nymph of beet leafhopper more harmful than the adult 18 



History of an outbreak of curly-top in the experimental field at Gar- 

 land, Utah 18 



Early sowing advantageous in preventing curly-top 19 



Extraction of plant juices not sufficient to account for the disease — 20 



Conditions favoring an outbreak of curly-top 21 



Natural and artificial barriers to leafhopper invasion 22 



Host plants of Eutettix tenella 22 



Description of the beet leafhopper 22 



Beet growers should be able to recognize the leafhopper 24 



Serious nature of curly-top 24 



A consideration of curly-top in seed beets 24 



Several types of leaf-curl on seed and sugar beets 28 



Affected seed beets almost nonproductive 29 



Percentage of loss of seed beets 29 



Severe outbreaks not frequent in a locality 31 



Progeny of the diseased seed beets healthy 31 



General character of curly-top__ 31 



Summary 33 



Conclusion 35 



Recommendations 36 



Bibliography 37 



Description of plates 42 



Index . 43 



Bulletin No. 182. — Ten Tears' Experience with the Swedish Select 

 Oat. 



Introduction 7 



Characteristics 7 



Results of trials in this country -_ 8 



Trials by experiment stations 9 



Wisconsin 9 



North Dakota 13 



Montana : 34 



South Dakota 16 



Washington 18 



Colorado 18 



Iowa IS 



Alaska 20 



Miscellaneous 20 



Trials by farmers 20 



Washington -0 



Idaho 21 



Colorado 21 



