— GO — 



severely from the attacks of this bhght during the dry summer weather. The 

 symptoms of the bhght are the withering of the leaves and the death of the canes. 

 Usually this is most marked about the time the fruit is beginning to ripen, but 

 may occur earlier. Examination of the diseased canes will usually show the 

 place of attack of the fungus. Here the canes are very brittle and the surface of 

 the bark shows small, dark-coloured, raised dots, the cases which contain the 

 spores. Usually the surface is sooty from the abundant spores exuded from the 

 spore-cases or pycnidia. The wood and pith will be found to be discoloured at the 

 place of attack. The spores readily find an entrance through wounds and infec- 

 tion takes place during the summer and faW but does not usually becoime evident 

 till next season. Another spore form is produced on the diseased canes in the 

 spring, so the scientific name of the fungus becomes Leptosphaeria coniotliyrium. 

 No effective measures of control are known. Cutting out and burning diseased 

 canes and cutting out the old canes as soon as the berries are picked will help to 

 prevent the spread of the disease. 



STORAGE ROTS OF* POTATOES AND OTHER VEGETABLES 



W. P. Fraser, Macdonald College, P. Q. 



Frequent'ly potatoes and other vegetables when in storage are attacked by 

 rot and serious losses result. In some cases a wet rot is present, in others the 

 vegetables are attacked by a dry rot, the decaying part usually being covered by a 

 white moldy growth. These rots are caused by either fungi or bacteria. The 

 fungi grow into the tissues of the vegetables and live at the expense of the ma- 

 terial stored there. Finally the tissues are broken down and destroyed. If suffic- 

 ient moisture is present bacteria may also attack the diseased vegetables and re- 

 duce them to a wet, i'11-smelling mass. Some bacteria may of themselves cause a 

 wet rot without the aid of fungi. 



A number of different kinds of fungi cause these rots which may for con- 

 venience be included in a few groups. A brief description of these groups may 

 indicate the reason for the methods of control suggested. 



I. — The Late Blight Rot of Potatoes. — This fungus frequently attacks and 

 kills the fo'liage during late summer, especiallly in moist weather. The spores of 

 the fungus fall to the ground, reach and infect the tubers, causing them to decay 

 before they are dug. When stored the rot may develop further and attack 

 healthy potatoes. This fungus is carried over winter in diseased tubers. If these 

 are planted the blight and rot may appear again next season, if the weather condi- 

 tions are favourable. 



2. — Dry Rots {Fusariuin Rots). — These rots are usually caused by fungi 

 which can 'live in the soil for several years. These fungi may infect potatoes, 

 mangels, turnips and some other vegetables, producing a slow dry rot when they 

 are stored. Generally white moldy tufts are present on the surface of the diseased 

 vegetables. In very moist storage conditions bacteria may invade the diseased 

 parts and bring about a wet rot accompanied by an unplleasant odor. 



3. — Soft Rots (Sclerotinia Rots). — These are also caused by fungi which 

 attack chiefly carrots, turnips and miangels, but do not usually attack potatoes. 

 They are sometimes very serious, spreading rapidly and causing a soft, wet rot 

 without much discoloration of the diseased tissues. These fungi may live for 



