OCR Text |
Show ; o SEED ROT OF POTATOES. Reports have already begun to come in of seed potatoes rotting in the ground. This trouble is caused by a fungus, or mould, that attacks the piece of tuber in the ground on the cut surface. The disease was so bad twmmmmmmmmmmmmmmmmmmmmummrmmmmmm. last year in some fields that ninety per cent of the seed rotted in the ground. In some cases this rot started start-ed so soon as to prevent the pieces of tubers from sprouting at all. In other cases it started later, rotted the seed, then the fungus attacked the stem. Plants may be found in any field during the season more, or less affected with this disease. The plants lost their green color and the edges of the leaves turn yellow or die. If the stem be pulled up, the bark will be found all right, but the splitting of the stem longitudinally will show the sap wood of the stem colored brown or yellow or in the last stages black. Microscopical examination of a cross-section cross-section of the stem will show the fundus, fun-dus, growing in the cells and across tlfeVisap tubes offiie.sCcmw fiber in H jury,- to a large cxtentrat least, xomes H from the, clogging of the sap circula- H tion by'thc hypha of this fungus. H This plant, or fungus, that causes H the disease, is one of the species of H Fusarium.' the same or similar to the H one that causes the' blight or- so- H called "sleeping disease" of life tonut- H to. No direct remedy is known for H it. One fact that is of some assist- H ancc in combatting it is that the'dis- H case is much more prevalent on land H previously planted to potatoes than on H alfalfa or clover land. Another thing H 1 1 H that is quite noticeable in studying thj IH nature of the disease, is that potatoes 4tH planted whole arc not attacked to H such an extent as the cut ones, be- H cause of the inability of the fungus to ' H get into the stem. H Treatment of seed with formalin, H corrosive sublimate, sulphur, lime, H etc, haw not given any perceptible H relief from it. H It is probable that in many cases H at least much of the disease is carried H to' the field in the -seed potatoes. The same fungus causes the "dry rot" of M potatoes in the storage cellars. It H has been very noticeable during the past winter that cellars with poor M ventilation, no matter how cool and dry they were, had a high per cent of M potatoes affected with this dry iot. M Good ventilation and a low a tern- M perature without da-ngcr, of frost fn " M the .cellar is probably the best safe; M guard against loss from this cause. H E. R. Biennett, Potato Specialist, Colo H rado Experiment Station, Fort Col- H |