Show DISEASE OF POTATOES dry rot fungus causes blight and wilt of crop history of Fus arlum as field trouble is a of comparatively recent record preliminary symptoms are green color by T F MANNS maims tho the dry rot of 0 potatoes potato ea has long lone been known as a storage trouble at intervals since 1824 there has been found al ed with this rot by different investigators a fungus of tho the gonus genus Fus Fusar arlum tum which has been variously designated but the history of the disease as a field trouble is of comparatively recent record on badly infected soils the disease Is characterized as follows tho the stand la is uneven though few of the hills are missing the early growth I 1 howing premature dying in the field on an area which has become infested with Fus arlum disease Is somewhat slow when the plants reach a height of 10 to 14 inches there Is an apparent cessation of growth the first indication of the disease Is usually conspicuous at this time the preliminary symptoms are a light green color of the foliage particularly ticul arly the lower leaves this Is ie accompanied companies companied compa nied led during the heat of the day by a partial wilting and an inward and upward rolling of the upper leaves leava tho the color gradually changes to a sickly yellow which slowly and evenly covers the affected vines the wilting and rolling of the leaves extends to all parts of the affected plants As the disease progresses the field takes on a mottled yellow to light green color the growth of the foliage Is greatly restricted the wil wilting t becomes more pronounced and there la 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 hilla will show only one or two vines afflicted plants which early succumb to the disease pull up easily ea manifesting a badly rotted condition of the root As a rulo iulo the blighted sterna do not tall fall but remain quite erect except for the drooping top there is much evidence to indicate that thit many growers are practicing potato rotations of too 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 pd sick fields should not be planted in potatoes again for at least five or six years and even longer timo time may be required to work tho the parasitic fungus from the soil boll grass and grain crops will undoubtedly eliminate tho the fungus from the soil quicker than will and cultivated crops the work of 0 the dry rot in improper storage causes an excess of N 1 2 showing a potato rotting in tho the soil from the Fus arlum disease moisture due to the drying up of the rotting tubers this excess moisture sture condition together with the added facility with which bacteria and de decay cay fungi may enter the already infected tubers brings about much complication in the form of soft or wet rots for which the Fusar lurn disease to ia primarily responsible elble under the average cellar storage conditions it Is quite safe to estimate the loss from dry rot and its complications at from one to five per cent |