14 CIRCULAR 74 0, U. S. DEPARTMENT OF AGRICULTURE 



may turn slightly more yellow but soften scarcely at all. All unrip- 

 ened pears need to be withdrawn from cold storage and held at higher 

 temperatures to ripen for eating. 



The optimum ripening temperature for most varieties is between 

 65° and 70° F. Bartlett has much better quality when ripened in this 

 range than at higher temperatures. Bosc fails to ripen normally at 

 lower temperatures. Kieffer has optimum quality when ripened at 

 temperatures between 60° and 65°. 



PEAR ROTS 



Blue mold rot and gray mold rot are the most important storage 

 rots in pears. Blue mold rot usually results from skin punctures. 

 Gray mold rot may start at ruptures of the skin or at broken stems 

 and spreads from fruit to fruit by contact. Once established, gray 

 mold grows slowly in cold storage, but having the capacity to enter 

 the unbroken skin of adjacent fruits, it often produces the so-called 

 "nest rot" when a whole group of pears is affected. The spreading 

 from one pear to another can be prevented by packing in wrappers 

 impregnated with copper. Sanitary measures in harvesting and pack- 

 ing, together with prompt cooling to temperatures of 29° to 31° F. are 

 important factors in preventing losses from decay. Lining the 

 orchard boxes with old newspapers is an important precaution to 

 take to reduce mechanical injuries and resulting infection. 



PEAR SCALD 



In pear scald the skin of the fruit becomes dark brown and soft 

 and sloughs off easily under pressure. The affected skin may become 

 almost black and affords entrance for the decay fungi that usually 

 follow. The disease does not appear until the fruit is aged in storage 

 from being held too long or at too high a temperature. Pear scald, 

 other than the type on the Anjou variety, cannot be prevented by pack- 

 ing in oiled wrappers, but susceptibility may be lessened by picking 

 before the fruit becomes too advanced in maturity and by storing at 

 temperatures of 29° to 31° F. 



ANJOU SCALD 



The Anjou variety is subject to a mottled surface browning or 

 blackening in storage. Unlike pear scald, this does not cause a skin 

 disintegration that is deep-seated, nor does the skin slough off. Anjou 

 scald can be largely avoided by picking fruit at the proper maturity 

 and packing it in oiled wrappers such as are used for apple scald. 



CORK SPOT 



Cork, or cork spot, is characterized by small regions of dark-brown 

 corky tissue appearing in the flesh of pears. When the affected tissue 

 is near the surface a small depression frequently appears, and the 

 skin at this spot may be slightly dark. The sunken areas on the sur- 

 face sometimes fail to appear until after storage. Anjou is the vari- 

 ety frequently affected by cork spot. The disease is related to growth 



