338 Diseases of Greenhouse Crops 



Bud Drop 



As the name implies, the young flower buds at a 

 very early age turn yellow and drop off. This drop 

 should not be confused with the drop produced by 

 the anthracnose disease. In the latter case, the 

 flower develops into a normal spike but it is at- 

 tacked soon by the fungus Glomerella rufomaculans 

 which girdles it at the point of attachment between 

 the flower and the peduncle. Here the flower often 

 drops off, leaving behind the beheaded peduncle. In 

 the former case, however, the minute young flower 

 bud never develops, instead it turns yellow and drops 

 off. There seems no doubt that the drop is a physi- 

 ological disease and is induced by an unbalanced con- 

 dition of the food elements in the soil. This may 

 occur in a soil that has been excessively fed or in a 

 soil that is lacking in plant food. 



Bud drop may be readily remedied by the appli- 

 cation to the soil of small quantities of muriate of 

 potash and acid phosphate. 



Mosaic, see p. 102. 

 Streak 



Caused by Bacillus lathyri Manns and Taub. 



Streak is a very serious disease of outdoor sweet 

 peas. Fortunately it is not known to attack green- 

 house sweet peas. 



Symptoms. Although not occurring indoors, the 



