Presently the weather is not conducive to further development of the disease at significant levels. Once evening temperature fall below 50 F disease developments slows. With the current trend the Fort Morgan forecast reads as unfavorable and will probably continue that way. The fungus survives from season to season on crop residue and is the primary source of subsequent sugar beet infection the following season. Under moist conditions the spores are splashed and blown to sugar beet leaves and germinate and enter the stomata.
Secondary spread is from leaf spots that develop.
In some instances the fungus has been carried on seed from regions where the disease has been severe. And while a lot is not known, it may carry over on some weed hosts. Other hosts are table beet, Swiss chard, spinach and most wild Beta species. Management Considerable research has been carried out on resistance in sugar beets but is not available on some of the other hosts. There is still a problem of neighboring fields providing inoculum and, if possible, new fields should be at least 300-500 yards from the previous year's site.