Feb. 3, 1919 * Physoderma Disease of Corn 1 39 



Delaware, Indiana, Kentucky, Maryland, Minnesota, iMissouri, Nebraska, 

 New Jersey, Oklahoma, South Dakota, Texas, Virginia, and West Vir- 

 ginia. It was also found in other sections of Kansas, southern Illinois, 

 and Ohio. The disease, however, has not yet been found beyond the 

 eastern part of Texas and Oklahoma, northward to southeastern South 

 Dakota and Minnesota. Likewise the northern border of the infested 

 zone extends from southern South Dakota and Minnesota through 

 southern Illinois, Indiana, Ohio, West Virginia, and Virginia, and along 

 the coast regions of Maryland, Delaware, and New Jersey (fig. 1). The 

 disease is apparently much less prevalent in the area west of IMississippi, 

 and north of North Carolina and Tennessee. The nature of the survey, 

 being less intensive, may be responsible to a certain extent for this con- 

 clusion. It is possible that the disease has spread almost, if not quite, 

 to its northern and western limits as permitted by certain weather 

 factors. 



FXONOMIC IMPORTANCE 



The nature of the fungus causing the disease is such that its ability 

 to produce serious injury to corn is limited by weather conditions, and 

 in any ordinary season only local damage need be expected. How- 

 ever, in certain humid sections of the South, where the time for com 

 planting may extend over a period of three or four months in each 

 year, weather conditions will more than likely be such as to favot a 

 serious development of the disease on some of the plantings. This 

 holds true especially for the South Atlantic and Gulf coasts and lower 

 I\Iississippi Valley. 



Barre (2, p. 23) says: 



The com disease caused by Physoderma sp. as mentioned in the report last year 

 has caused serious loss again this year. This disease was collected during the past 

 season at a number of widely separated points in the state and seems to be more 

 wide spread than ever before. Tliis disease certainly deserves some attention and 

 it is hoped that an investigation of its life history and habits can be undertaken in 

 the near future. 



The disease w^as known to be causing loss to the corn crop in Florida 

 and Mississippi in 191 5. 



During the survey of 191 7 the most pronounced losses were found 

 along the Atlantic and Gulf coasts and in the Mississippi Valley. In 

 the lowlands of North and South Carolina, and in the Gulf and Delta 

 sections of Mississippi, frequent reports of as much as 5 per cent loss 

 were given by the sur\^ey men. In some cases the damage was estimated 

 at 6 to 10 per cent of the crop. The v/riter visited a few fields in the 

 eastern part of South Carolina where the damage was perhaps as much 

 as 10 per cent. Fields of this kind, however, were seldom found. These 

 estimates were based entirely on grain loss, whereas the foliage, v.hich 

 is not considered of great importance except where the plants are used 

 for silage, etc., was often badh' injured. Smaller areas sustaining con- 



