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Show FUSARIUM OF POTATO Too Much Water and Heat Cause of Disease. Exact Conditions Have Been Discovered Discov-ered by Expert of Colorado College Preventive ' to Be Placed Within Reach of Raiser. The exact -conditions which cause 'fusarium," the disease, which caused a loss of more than. $20,000,000 to the potato crop in the southernmost potato-raising states from Colorado to Chio and Pennsylvania last year, have been discovered by Prof. C. L. Fitch, potato expert at the Colorado Agricultural Agricul-tural college. Experiments to determine deter-mine what these conditions are have been under way in a greenhouse at the college here for the past 100 days and are just coming to a close. The results sought just what combination combina-tion of soil temperature and water supply cause the disease have recently re-cently been made manifest. The result Is that Prof. Fitch has obtained data by which he will be able to advise the potato raiser as to what measures. to adopt to make the disease less likely to affect his crop. A cure, however, has not yet been discovered; for, after the disease appears ap-pears there is no means of stopping it. But the result Is that means of preventing the disease, to a very great extent, will be placed within the reach of the potato raiser. "Fusarium" is not a new disease. It is an '.meeting cf the potato plant which makes itself manifest in very hot, dry seasons, like last season. To secure the data mentioned Prof. Fitch created in one of the greenhouses green-houses at the college the very same conditions that exist in the potato field in the summer. The temperature in the four . cabinets where the experiment experi-ment svas carried on was kept at 50, 65, SO.' and 93 degrees, and the moisture mois-ture was regulated at 10, 20, 30 and !0 per; cent. When the plants reached the proper stage of development samples sam-ples from each cabinet were placed in the 95 degree cabinet and enclosed in f,"!;iss and. by means of electric light i. the temperature was raised to betwp'en 90 and 100 degrees such temperal ures as are found in a potato field on a moderately hot summer day. Tins glass cabinet was so arranged its to supply proper circulation of air, as "Viearly as possible imitating the av.?3Se summer breeze. The moisture-was raised on half the hills to "0- and 40 per cent, and the final test was- on. The plants were put in the glass cabinet on a Monday morning. Wednesday Wed-nesday morning fusarium developed. The plants were decidedly "sick," and 'Tiefore night it was evident that they -were dying. The experiment had been successful and Professor Fitch had cause to rejoice. The plants which had been supplied 'with' 30 and 40 per cent of moisture showed the effects of the disease sooner soon-er -and died more rapidly, while those which had been supplied with 20 per cent withstood the test longer, but finally fi-nally showed . signs of the disease. Those which had 10 pe cent are still 'healthy. From -these experiments Professor Fitch had determined that, to irrigate irri-gate potato fields past 20 per cent of moisture-. when the temperature of the .soil Is above SO degrees, will certainly certain-ly produce "fusarium" and also pre-!y pre-!y produce "fusarium" to take hold. He also found during the experiment experi-ment that a soil temperature of about 70. degrees, with an application of 20 per cent, of moisture, supplies almost ideal conditions for potato raising. :Of course, the results of the experiments experi-ments do not mean that the problem has been solved, for there are yet to be: devised methods of putting the ln-fui-matlon to practical use and of doing do-ing what. may be done to cool the soil. V'A special thermometer for the farmer's farm-er's vise in testing the soils is one of the needs. .Vlth this he can ascertain just at what time It will be safe to irrigate'- his' fields. AH these new facts ajpprove the' practice of careful old farmers who think that during the ritittest period of the summer it is wise to Irrigate at night. Professor Fitch believes that, under the most adverse conditions, the temperature tem-perature w-ill be so lowered by midnight mid-night that It will be safe to apply the winter at that time, and that before the beat of the next day is cast upon the fields this water will have done its work in supplying the plants and will have soaked away Into the soil so that the heat will not cause the disease. : Another feature which will prove valuable is the method of preparing t.he seed bed and pushing the plant to e'ftrly growth, it Is believed that by applying sufficient moisture to the seed bed to dampen it deeply without soaking and pushing the growth of the plants as rapidly as possible early In the season, before the hot weather oomes, the plants themselves will furnish fur-nish a shade to the soil which will be the chief aid In the battle against the disease. The importance of this work may be judged by the loss to Colorado alone, estimated to have been not less .than $S. 000, 000 on last season's crop, based on average prices. |