GRASSHOPPERS AND OTHER INJURIOUS INSECTS OF 1911 AND 1912. 53 



Plants attacked are in no way injured for hay, but it is evident 

 that the method of handling the hay crop has a direct bearing upon 

 the infestation of the seed crop following. Red Clover, Mammoth 

 and Medium, and some species of Alfalfa are attacked. We have 

 not found it on Alsike or on White Clover, nor does it apparently 

 work on Sweet Clover, 



While the chief interest was centered in an effort to discover 

 some method by which a larger yield of seed could be harvested in 

 Minnesota, certain ecological questions, having more or less bear- 

 ing it may be said upon the practical treatment of the pest, present- 

 ed themselves for solution. Therefore, the details of the work were 

 classified under two heads : 



1. Economic; i. e., methods of control. 



2. Biological or ecological ; under which may be included the 

 study of food habits, oviposition, incubation period, parasitism, 

 number of progeny from single adult, number of generations in a 

 year, period of most abundant emergence, and of the most abun- 

 dant oviposition, period of life development, and its variation if 

 any, length of larval life, of pupal stage, etc. 



As stated above the details of work and results will later prob- 

 ably be made a subject for a station bulletin, and it would be out of 

 place to insert them here at this time. Briefly, however, it may be 

 stated that from our work of several years upon this pest, we con- 

 clude that a farmer desirous of raising seed, can secure a much 

 larger crop by cutting the hay crop preceeding the seed crop, while 

 the heads are still green or just coming into bloom, thereby pre- 

 venting the maturing of the Chalcid and the consequent attack 

 upon the heads of the seed crop appearing later in the same field. 

 Manifestly, co-operative action amongst farmers of a neighborhood 

 is necessary in this work. Otherwise a stand of clover which prom- 

 ises well for seed may be infested from an adjoining field where 

 the above precautionary measures have not been taken. The ex- 

 periments leading to these conclusions were conducted upon one, 

 two, four and five acre plots on farms near Wadena, Audubon, 

 Chatfield, Simpson and Verndale, but were supplemented by very 

 many field observations and laboratory experiments. The above 

 recommendation applies to Medium Red Clover only, not to Mam- 

 moth Red Clover. In addition to the above recommendations we 

 might also advise the destruction or early cutting of all volunteer 

 Red Clover along roadsides, fences, etc., and also the cleaning up 

 and destroying of all clover waste about the huller. It is probable 

 that where little or no earth covers seed, the insect may emerge in 



