16 Robert S. Kirby 



Surveys were made in 1921, 1922, and 1923 in cooperation with the 

 Plant Disease Survey of the United States Department of Agriculture, 

 to determine the distribution of take-all in New York During those 

 three years the surveys extended over fifty-seven of the sixty-two counties 

 in New York, and included all sections where spring or winter wheat is 

 commonly grown. The location of all take-all-infested winter-wheat 

 fields found during these three surveys is shown in the accompanying 

 map (figure 1). 



Plants affected with take-all were found in 205 out of the 538 winter- 

 wheat fields surveyed. The 205 infested fields were located in eighteen 

 counties in the west central part of the State. This infested area seems 

 to have definite boundaries, and coincides closely with the principal winter- 

 wheat-producing area of New York. Within these eighteen counties, 

 48 per cent of the fields surveyed during the years 1921 to 1923 were found 

 to be infected. 



ECONOMIC IMPORTANCE 



Take-all is one of the most serious diseases of winter, wheat in the 

 countries where it occurs. Its importance varies from year to year, 

 depending at first on the climatic conditions; but later, when an area is 

 once infe ted, the importance of the disease seems then to depend largely 

 on whether or not rotation is practiced. Continuous cropping always 

 results in increasingly greater losses; for example, in the Union of South 

 Africa, where this is the prevailing practice (Anonymous, 1922 a), take- 

 all results in an enormous amount of damage, and losses up to 100 per cent 

 are reported. Hardly a field is free from the disease and it spreads rapidly. 

 It is said that wheat-growing in the infested area there will soon be a 

 thing of the past unless rotation is adopted. In Australia, where crop 

 rotation is the exception and not the rule, many fields are almost entirely 

 useless for wheat; and Mackinnon (1920) states that take-all reduces the 

 average yield of Australian wheat fields from 12 to 15 per cent in certain 

 years, although the average reduction for all years is probably not more 

 than 7 per cent annually. In the United States, Stakman (1922) says 

 that at Hillsboro, Oregon, the loss is estimated at one-third of the crop, 

 and it is further reported (Anonymous, 1922 b) that in the same year, 

 in that State, a considerable number of fields were so damaged as not to 

 be worth threshing. In New York where rotation is usually practiced, 

 the loss in the infested area varies from 0.3 to 2 per cent, although losses 

 as high as 20 per cent have been observed in individual fields where rota- 

 tion was neglected. 



This disease causes a marked dwarfing of all parts of the wheat. The 

 effect of the different degrees of dwarfing on the varieties of winter wheat 

 grown in duplicate plots at Ithaca are shown in fable 3. With increased 

 severity of the disease as indicated by the degree of dwarfing, there is ;i 

 proportionate decrease in the number of heads per plant, the number of 



