ENEMIES OF WHEAT 



97 



Known remedy. A great deal of study has been given to the discovery or production 

 of rust proof varieties of wheat, with as yet little if any success. 



147. Wheat Scab. — The scab fungus is believed to be the conidial stage of a 

 fungus which in its ascigerous stage is called Gibberella saubinettii (Mont) Sacc. 

 The fungus attacks the glumes, causing dead sections of the 



spike, whose brown color is in striking contrast with the green 

 healthy glumes. At times the whole spike is destroyed. It 

 may be identified by the pink incrustations at the base of the 

 dead glumes and covering the rachis. 



Usually the losses are inconsiderable, although under 

 conditions favorable to the fungus, it may amount to ten per 

 cent or more. There is no remedy known, but where wheat 

 is to follow scabby wheat the burning of the stubble has 

 been recommended.l 



148. Loose Smut. — This fungus belongs to the same 

 genus as the smut so commonly found on maize. The 

 spores adhering to the grain germinate and enter the young 

 wheat plant through the sheath of the first leaf. The fungus 

 grows within the wheat plant without external manifestation 

 until the wheat plant is about to flower, when the whole spike 

 except the rachis is reduced to a mass of black smut spores. 



The loss from loose smut is rarely large, although as high 

 as eight per cent has been reported.2 The remedy is known 

 as the modified hot water treatment and is as follows : 



Soak the seed grain for four hours in cold water, let stand 

 for four hours more in the wet sacks, then immerse for 

 five minutes in water at a temperature of 133° F. ; then dry 

 and sow.3 Since this treatment injures the germinating 

 power of the seed, one-half more seed per acre is required. 

 The purchase of non-infected seed is also to be recommended. 



149. Stinking Smut. — Stinking smut is closely allied to the loose smut of 

 wheat, in form and habit, although differing from it in the character and extent of 

 its injury. It affects only the grains, which are considerably enlarged, the interior 

 being converted into blackish, offensive smelling masses of spores, which, when they 

 find their way into the flour, make it unfit for food. The glumes being unaffected, 

 the disease often escapes observation until after the grain is threshed. Losses from 

 this smut are rather general and often considerable, amounting in some instances to 

 at least forty per cent, which, practically speaking, ruins the crop. 



Any one of the following remedies has been found effective : 



(i) Hot water: Place seed in any bag or basket which will readily admit water 

 and immerse fcr ten minutes in hot water at 133*' F. ; then cool quickly by immers- 

 ing in cold water or by stirring thoroughly while drying. 



1 Ohio Bui. 97, p. 42. 



2 Ohio BuL 42, p. 93. 

 8 Ohio BuL 97, p. 60. 



Wheat spike with 

 scab : Upper por. 

 tion has been de- 

 stroyed by t h • 

 pink fungus. One- 

 half natural size, 

 (After Selby.) 



