60 MISC. PUBLICATION 168, U. S. DEPT. OF AGRICULTURE 



care should be exercised to sort out any with partly decayed 

 stems or to cut these stems off below the affected part. Prompt 

 cooling of the fruit reduces the seriousness of the disease, but 

 the causal fungi can continue to grow and produce decay at the 

 usual cold-storage temperatures. 



Good packing-house sanitation and careful handling of fruit 

 to prevent abrasions and bruises are of value in preventing de- 

 velopment of the disease in storage. The most practical method 

 of preventing spread of the rot from one fruit to another is use 

 of copper-treated wrappers. Such wrappers are generally used at 

 the present time. Wrappers treated with soluble copper compounds 

 such as copper sulfate may cause injury if the pears are wet 

 when packed. This injury is exhibited as irregularly shaped 

 black spots scattered over the surface of the fruit (pi. 11, E). At 

 present commercial wrappers are usually impregnated with a 

 more stable copper compound, which does not cause injury. 



Recently sodium chloro-2-phenylphenate as a disinfecting wash 

 for apples and pears has been used on a commercial scale in 

 certain producing sections of the Northwest. Treated pears show 

 a substantial reduction in gray mold rot, as well as some reduc- 

 tion in other kinds of decay. In packing houses using the treat- 

 ment, precautions are necessary to protect workers from ex- 

 cessive contact with the solution or with fumes from the washing 

 tank. 



The fruit is usually uninjured by the treatment, but injury 

 occasionally occurs. The cause of injury cannot always be deter- 

 mined. Some possible causes are concentration of the chemical 

 resulting from evaporation of drops of the solution adhering to 

 the fruit, insufficient wax on the fruit, and reduced alkalinity 

 of the treating solution. There is indication that injury may result 

 when the reaction of the treating solution is less than pH 8. 



On pears the injured areas may occur anywhere on the fruit. 

 They are black and are not sunken at first, but they may even- 

 tually become sunken (pi. 11, G, H). On apples the injury re- 

 sembles soft scald somewhat. The affected areas are medium 

 brown. They lack the large patterns with sharp margins char- 

 acteristic of soft scald and usually are not sunken. Injury occurs 

 in the calyx basin more frequently than elsewhere (pi. 5, D). 



(See 29, 30, 38, 56, 75, 76.) 



Pear Leaf Blister Mite Injury 



(Eriophyes pyri (Pgst.) ) 

 OCCURRENCE and symptoms 



Two types of injury by the pear leaf blister mite may be found 

 on pears and also on apples: A diffuse russeting, usually most 

 marked at the calyx end, and irregularly shaped, depressed, 

 russeted spots % to V£ inch in diameter, most of which are 

 eventually surrounded by a zone of almost decolorized skin (pi. 

 11, D). Severely infested fruit may be considerably distorted. 

 This mite is widely distributed over the United States, but on 

 the market the injury is seen most often on fruit grown in 

 Pacific Coast States. 



