10 BULLETIN 686; U. S. DEPAETMENT OF AGRICULTURE. 



which has been attributed to Botrytis (7, p. 950) is apparently largely 

 due to its frequent occurrence in strawberry fields under certain cir- 

 cumstances and to its ability to produce aerial hyphse at relative^ low 

 temperatures. Under the conditions found in many refrigerator 

 cars, strawberries affected with Botrytis often develop abundant 

 fine, gray, sterile aerial hyphse, often 2 cm. or more in length. A few 

 such berries on the top of a crate attract immediate attention and give 

 the impression of general decay. On removal from the cool, moist 

 air of the refrigerator car these aerial hyphge collapse and are replaced 

 by much shorter (2 to 3 mm.) fertile hyphse, whi^h produce mature 

 spores in a short time, often within 36 hours. 



The ability of Botrytis to grow at low temperatures has been 

 frequently noted. Brooks and Cooley (2, pp. 156 and 159, fig. 15) 

 found that it would grow somewhat at 0° C. on corn-meal agar in 

 Petri dishes and would even germinate at this temperature, while 

 Fulton in the course of storage experiments on small fruits found that 

 this fungus (3, p. 19) "grows luxuriantly in warm temperatures and 

 slowly in the coldest temperatures in which the fruit can be stored 

 safely without freezing." (See also 3, pi. 1, D, and pi. 3.) 



The fact that berries destroyed by Botrytis are frequently browTiish 

 when they arrive at their destination has caused some inspectors to 

 apply the term "brown-rot" to this disease. This name is, however, 

 unfortunate, since it is now customarily limited in application to a 

 different class of diseases. 



In striking contrast to strawberries rotted by Rhizopus, those 

 affected by Botrytis are even firmer than normal berries, retaining 

 their shape even after abundant spores are produced and finallj' 

 becoming hard and dry. For this reason, therefore, and because 

 Botrytis is a field trouble rather than a rot of berries in shipm.ent, it 

 seems that the descriptive term "diy-rot," already in use among 

 growers in some sections, might well be applied to this disease. 



RELATION OF BOTRYTIS TO INFECTION BY RHIZOPUS. 



In his first paper dealing with decay of strawberries in transit, 

 F. L. Stevens regarded Botrytis as a primary cause of decay in transit 

 and stated that "Botrytis initiates the deca}^, opening the way to 

 such other saprophytes as may be present. Of such saprophytes 

 Rhizopus is by far the most prominent and most abundant." On the 

 basis of a histological study of strawberries infected with these two 

 fungi, one of the writers stated in 1916 that Rhizopus ordinaril}^ 

 entered strawberries through wounds and was "not dependent on 

 the presence of any other fungus in its attack on strawberries during 

 shipment and on the market" (10, p. 366). It was, of course, recog- 

 nized at this time that these observations did "not preclude the 

 possibility of Rliizopus sp. following in an area originally infected by 



