DISEASES OF CULTIVATED PLANTS 653 



Storage Rots of Apples and Pears. With apples the common- 

 est storage rot for our district is doubtless also the commonest orchard 

 rot, namely, black-rot, due to the black-rot fungus, Svhaeropsis ma- 

 lorum. All are familiar with orchard conditions liable to prevail at 

 ripening time. This* fungus is generally found, especially in or- 

 chards of mixed varieties, because some sorts are commonly attacked 

 by it. The same fungus causes cankers upon branches of the sus- 

 ceptible varieties and is usually well distributed over orchards. 

 The punctures of worms or of bees, or wounds caused by mechanical 

 injuries such as occur in wind-falls, and the various drops at pick- 

 ing time, afford easy entrance for the fungus. In consequence we 

 must expect that the fruits which have been in any way punctured 

 or injured, have also been exposed to infection by the iblack-rot fun- 

 gus. Such infected fruits are very liable to rot because of the prog- 

 ress of the fungus, if conditions are favorable. The high tempera- 

 tures of storage sheds and ordinary freight cars during October 

 and early November in our climate, are such as favor its develop- 

 ment. 



In the light of our present knowledge the best we can do is to 

 transfer fruit as soon as possible to storage where the temperatures 

 are low enough to restrict the fungus. It follows without saying, 

 that good results are obtained only from absolutely sound fruit, and 

 the low temperatures of cold storage houses, 42 degrees or below, may 

 be relied upon to check this rot to a very large extent, provided 

 only sound fruits are placed in storage. 



Naturally the discussion which follows under the storage of 

 onions will raise the question here as to the practicability of gaseous 

 disinfection of apples by the use of formaldehyde gas. It would 

 seem possible under favorable weather conditions when fruit can be 

 gathered dry and brought into storage houses in that condition, to 

 disinfect the fruits by the formaldehyde gas method. Of course it 

 follows that the period of disinfection will be brief in order that 

 little or no gas will be absorbed by moist or exposed fruit surfaces, 

 since formaldehyde is objectionable in food stuff. The time of fumi- 

 gation may not need to be more than about half that used for 

 potatoes or onions, and the strength of the formula may even be 

 modified. The aim would be the destruction of external spores, etc., 

 which certainly are a menace at all times. 



The bitter-rot fungus (Glomerelia rufomaculans) may also de- 

 velop in storage apples where these have become attacked by it be- 

 fore harvest. The bitter-rot may be more common upon late sum- 

 mer and fall varieties in transit, than in ordinary winter storage. 

 Certain sweet apples, such as Bentley Sweet, are very susceptible to 

 bitter-rot losses in storage. Cold storage temperatures hold back the 

 development of the fungus, but cannot disinfect the diseased fruits. 



Pear rots with us are almost exclusively those which occur in 

 the orchard. The leaf-spot fungus (Entomosporium maculatum) 

 also attacks the fruits of pear and may become a source of loss in 

 storage. This applies more particularly to inferior grades of fruit. 

 Pacific coast fruit which is shipped to our district, may further suf- 



