EXPERIMENT STATION BULLETINS. 295 



rnethods have beeu discovered which will completely eradicate it. Fields 

 that are attacked by leaf spot should be clipped soon after the lower 

 leaves turn yellow and begin to fall off, or when the alfalfa stops grow- 

 ing and the leaves are covered with brown spots, even though little 

 or any of the yellow ai)pearance develops. The cutting of the al- 

 falfa will cause a new growth which will be less affected with the 

 disease than the older growth and usually when conditions are favor- 

 able, the new crop will nialce about the normal growth. 



While there are many insects that work on alfalfa, the depredation 

 of the grasshopper is the most serious, especially on the light soil 

 types of the northern part of the state. The new seedings of alfalfa 

 frequently provide a succulent green growth w^hen there is little other 

 green growth in the neighborhood and it is especially subject to attacks 

 of the grasshoppers, an entire field frequently being destroyed in a 

 few days' time. 



The following methods of combating grasshoppers are recommended 

 by Professor R. H. Pettit in Michigan Bulletin No. 258. 



''Fall plowing. — This is the most efficient where it is possible at all. 

 Plow the egg-pods under, burying some, and breaking open others so 

 that moisture can get in, and exposing still others to the attacks of 

 their enemies, — birds, shrews, etc." 



"Poisoned baits. — The second method is that of poisoned baits. Use 

 either poisoned bran or the Criddle mixture. Poisoned bran can be 

 used only in situations where stock and poultry are excluded. Neither 

 should it be used where partridge or quail are likely to feed. It is 

 merely bran poisoned with paris-green or arsenic, two pounds of paris- 

 green to 100 of bran, moistened with water and a little molasses, so that 

 the bran will just stick together when taken up with a spoon." 



''Criddle mixture is horse-manure mixed with arsenic and slightly 

 salted. It is to be distributed about the fields in small masses. We 

 all know of the fondness of grasshoppers for anything containing salt. 

 They will even roughen fork handles in their efforts to get at the salt 

 deposited on them with the perspiration. This mixture is recom- 

 mended in Canada and in some of the western states. The proportions 

 are about as follows: Paris-green, one pound; salt, two pounds, fresh 

 horse-droppings, 100 pounds. The horse-droppings are usually measured 

 out in a three-gallon pail. Five pailfuls being taken as a right amount 

 for one pound of the poison. The salt is dissolved in a pail of water, 

 the poison stirred in, and the whole mixed with the droppings in a half 

 barrel." 



WEEDS IN ALFALFA FIELDS. 



The worst weeds in alfalfa fields are the perennial grasses, such as 

 Kentucky blue glass (June grass) and quack grass. In some sections 

 of the state the late summer annual grasses such as crab grass, are 

 serious pests. Both of these types of grasses after once being estab- 

 lished in the field are very difficult of eradication, the only feasible 

 method of control, especially for the first mentioned type, being a 

 thorough preparation of the seed bed, as previously discussed in this 

 bulletin. When the alfalfa field becomes unproductive because of the 

 foothold gained by Kentucky blue grass or other perennial grasses, it 



