Show DISEASE OF POTATOES dry rot fungus causes blight and wilt of crop history of Fui Fus arlum as field trouble I 1 Is of comparatively recent rec ord preliminary Prell symptoms aro are green color by T r F MANNS the dry rot of potatoes has baa long been known as a lo at intervals since 1824 there has been found associated with this rot by different investigators a fungus of tho the genus gentle blis arlum which has baa been variously designated but the history of tho the disease as a field trouble is of comparatively recent record on badly infected bolls the disease to Is characterized as follows the stand Is uneven though few of the hills are missing the early growth showing premature dying in the field on an area which has se be como come infested with Fusar Fus arlum lurn disease Is somewhat slow when tho plants reach a height of 10 to 14 inches there is an apparent cessation of growth the first indication of the disease la is usually conspicuous at this time the preliminary symptoms aro are a light green color of the foliage particularly ticul arly tho the lower leaves this to la accompanied compa nied during the heator heat of thin the day by a partial wilting and an inward and upward rolling of the upper tipper leaves the color gradually changes to a sickly yellow which slowly and evenly covers the affected vines the wilting and rolling of the leaves ox ex tends to all parts of the affected plants As ae the disease progresses the field takes on a mottled yellow to light green color the growth of the allago la Is greatly restricted the wilting becomes more pronounced and there Is associated much tip burn owing to the failure of the leaflets to fully recover at night from the wilt of the midday mid day occasionally hills will show only one or two vines aMic afflicted ted plants planta which velch early succumb to the disease pull up easily manifesting a badly rotted condition of the root As a rule the blighted stems do not fall all but remain quite erect except tor for the tha drooping top iop there la is much evidence to indicate that thal inny growers are practicing potato rotations of too short abort a duration most of such growers have attempted to maintain a three year rotation of wheat clover and potatoes but longer than a three year rotation should be practiced sick fielde should not be planted in potatoes again for at least five or six years and even longer time may be required to work the parasitic fungus from the soil coll grass and grain crops will undoubtedly eliminate the fungus from the soil quicker than will and cultivated crops the work of the dry rot in im proper storage causes an excess of tj ki showing a potato rotting in the soli soil from the Fus arlum disease moisture due to the drying up of the rotting tube tubers rs this excess moisture condition together with the added facility with which bacteria and decay fungi may enter the already infected tubers brings about much tion in the form of soft or wet rots for which the Fusar Fus arlum lurn disease e la Is primarily responsible under the average cellar collar storage condition a it Is quite sate safo to estimate the 10 loss 1 as from dry rot and its complications at from one to five per cent |