The Botrytis Blight of Tulips 



321 



Under warm, humid conditions, a large part of the outer scale may 

 become affected, and in some cases it is so densely covered with sclerotia 

 that these coalesce and form a crust. 



Care must be exercised not to confuse the lesions on the bulbs due to 

 the very common Penicillium rot with those caused by Botrytis Tulipae. 



Fig. 23. botrytis blight lesions on the bulbs 



The lesions in the outer, fleshy, bulb scale are depressed and show sclerotia on their surface. 



Natural size 



Tin's is especially true of the incipient lesions which, in these two diseases, 

 are often found almost impossible to differentiate. In general, the lesions of 

 the Penicillium rot are more indefinite in outline and of a lighter yellow 

 color, are usually raised and uneven, and do not, of course, have sclerotia 

 on their surface The appearance of green mold, which forms under favor- 

 able conditions, is a distinguishing characteristic. 



