3 - 



skin such as are caused by stem punctures, nails in boxes, insect 

 stings, bruises in picking and handling, sun scald, chemical injury, 

 limb rub, apple powdery mildew russet, or other rots. Entry may 

 occur also at the stem, at the calyx end and by penetration into an 

 open calyx canal . 



Although the fungus commonly enters through an injury, it does 

 not need a puncture or injury to enter an apple. It can enter 

 through the lenticels, and lenticels are in fact the most common 

 place of entry late in the storage period. Rot increases consid- 

 erably after 180 days in cold storage. At that time, the lenticels 

 are more vulnerable to entry and the flesh of the apple more mature 

 and more susceptible to rot. 



a relationship between temperature and the length of 

 for rot to get started and the rate at which it grows 



negligible at 32 F even after 8 weeks 

 may involve one-third of the apple at 



1 n^stor- 

 41°F, 



There is 

 time it takes 

 Development of rot is 

 age, by which time it 



and the entire apple at 50" or higher. Blue mold rot starts slower, 

 and there is less of it early in storage, if apples are picked be- 

 fore fully mature and placed in cold storage and cooled down without 

 delay. After 180 days in storage, low temperatures do not seem to 

 s 1 ow it down much . 



SOME THINGS A GROWER CAN DO TO REDUCE LOSS FROM BLUE MOLD 



1. Obviously, if the blue mold fungus does not have something 

 suitable on which to grow, it will not produce spores to cause 

 storage rot. A grower can get rid of some things he does not 

 need, outside and inside his storage and grading rooms, such 

 as rotting wet boards, broken apple boxes, debris, trash piles 

 and rotting apples - and do it often. In the home, this is 

 called Good Housekeepi ng ! 



2 . Kill Bl ue Mol d Spores - Decontaminate picking baskets, picking 

 and storage boxes, lugs, and crates, grading equipment and 

 walls, ceilings, and floors of grading and storage rooms. (It 

 is estimated that an old apple box may have more than 32 million 

 blue mold spores on it). There are several ways of doing it and 

 the method a grower selects will depend on the job that needs 



to be done. 



(a) Streaming Steam (Live steam) - An exposure for 2 minutes 

 kills blue mold spores on surfaces, between boards, in 

 cracks and joints and even in dried rotted apple tissue. 

 It leaves no residue to offend anti -pesti ci de crusaders. 

 A steam jenny is a handy thing to have around. 



(b) Sodium hypochlorite - This is the active ingredient (5.25%) 

 in household bleach, such as Clorox and other brands, which 

 releases available chlorine. Chlorine is used to make 

 drinking water supplies and swimming pools safe and for 

 other disinfecting purposes. 



