Show Spot Leaf-Spot Causes Big Beet Loss Losses s May l Be Controlled to Some Degree by Timely Dusting Dust- Dust ing illg or Spraying t c Prepared red by bv tho United States Department of or Agriculture The spot leaf disease of su sugar ar beets which Is responsible for serious losses to beet heN gro vcrs in In sonic some areas areaR may be controlled to a considerable de degree decree ree b by spraying or dusting say experimenters of the bureau of plant Industry In Circular C published by the United States Department of or A ture tune The he development of the disease depends primarily on temperature conditions conditions con on and the distribution of or rain fall Only In years ears of unusual weather conditions does Ines the spot leaf disease cause severe losses In the eastern area of sugar-beet sugar culture The fhe situa situation tion Is more serious In Iowa southern Minnesota Nebraska and northern Colorado the disease does Its greatest greatest great great- reat est damage In the Arkansas valley of southern Color Colorado llo and It Is only In exceptional years that beet growers escape serious losses Cause of Disease The disease Is caused by hy a parasitic fungus which Is Introduced Into the field held b by Infected see seed or It mn may enter as wind blown spores The spore spore- bearing material from the beet tops nn and refuse of or a 0 previously diseased held field Is the most Important source of oC Infection Long rotations help to restrict restrict restrict re re- re- re strict the infection Careful control of Irrl Irrigation and good drainage In beet heet fields create conditions unfavorable unfavorable able for the multiplication and spread of the parasite There Is hope that plant breeders may eventually develop beets heets of commercial value alue which are resistant to the spot leaf disease In Inthe Inthe Inthe the meantime the Department of Agriculture Agriculture Agri Arl culture offers the results of spraying In un and dusting experiments which promise promIse promise prom prom- ise to be of value to growers rowers particularly particularly in the areas where spot leaf damage Is severe For control of spot leaf In the vicinIty vicinity vicin vicin- ity of ot Rocky Ford Colo either bordeaux bordeaux bor bor- deaux spray or copper sulphate-lime sulphate dust applied from three to live five times during the growing season at Intervals intervals Inter Inter inter- vals als of approximately two weeks gave favorable results The treated plots on the n average vera e produced a hen heavier vier tonnage of beets heets and the beets showed showe a higher sugar content The cost for fora a seasons season's dusting Is estimated at ot SO SOto G to SS 8 S an acre with the probability that the cost can cnn be reduced If dust eust- d in III ing tit 1 curries common 10 to warrant warrant war war- rant development de of efficient machinery machin ery and the purchase of materials In carload lots The rile gains from treatment treatment treat treat- ment nt mea measured In In Increase In fn tonnage tonnage ton ton- nage and sugar sometimes amounted to 20 20 an acre or more Heavy Spot Leaf Toll Present knowledge of or spot leaf-spot epi epi- does not nut permit forecastIng forecast- forecast Ing I the he years e rs of or heavy y spot leaf oc- oc Sll say the nut authors hors of or circular r C llo-C nn and such plant protection must mast he viewed a as a fi form of crop ance From tine the experience of the last iO 21 lI years ears In iii the Arkansas valley of In which all nil but hilt tour four or five fhe have e been heen years of heavy V leaf spot leaf spot toll loll such Insurance seems seelUs warranted for that area urea In n mall many other areas such us liS Michigan for example this type of plant protection will probably be lp most serviceable as an on emer emergency ency control ant rol measure l j Interested In the details of I the he experiments and anal in the discussion of the tile application of oC time the experimental results may un obtain a copy of circular 1 C. HC The Tiie Sugar Beet Lt Spot Leaf Disease Disease Dis Dis- ease pase and Its Us Control h by Direct Meas l ures lIres h by U applying III In to the Office of Information In In- formation United States Stats Department of Agli Agriculture Washington I ton D D. C. C |