^ O. M.Scott & Sons Co., Marysville, Ohio ff i 



areas. As the day progresses and the sun becomes more in- 

 tense, these spots turn brown, as if touched by fire. 



Such a condition is now known to be the result of a fung- 

 ous growth, not of the burning sun. This growth, Rhizoc- 

 tonia solani, is a soil organism which attacks a large num- 

 ber of plants and grasses. It forms on dead stems and leaves. 

 When germinating, a cobwebby covering called mycelium 

 or "mildew," is caused, through whose agency the grasses 

 are killed. The areas in which this disease may gain a foot- 

 hold are often very small, but sometimes they approximate 

 several feet in circumference. Under favorable conditions 

 the "brown patch" infection may spread for several succes- 

 sive days, or, under adverse circumstances, such as cooling 

 weather, it may terminate in a single night. Those noting 

 that a dose of "brown patch" very often follows a thunder 

 shower have attributed the disease to this cause. However, 

 it is definitely known that the thunder showers themselves 

 are not responsible, but that "brown patch" is favored by 

 hot, muggy weather. 



Numerous experiments have been performed in the hope 

 that some definite means of stamping out the disease might 

 be developed. Unfortunately, there is no certain remedy, 

 although frequent sprayings of half strength Bordeaux have 

 held the plague in check. This, however, is an expensive 

 and tedious remedy. To be effective, Bordeaux must be kept 

 on the leaves of the grass continuously, for it is a preven- 

 tive and not a cure. The necessity of spraying daily or three 

 to four times a week will depend upon the frequency of 

 showers that wash away the Bordeaux covering. Bordeaux 

 dust may be used and is easily applied. The bare spots left 

 by "brown-patch" can usually be revived by liberal ap- 

 plications of compost and sulphate of ammonia. 



[30] 



