52 THE APPLE LEAF HOPPER 



wingless form were found the following day on Paiiicum capillare in 

 the same locality. At Olivia on July 25th and at Ortonville on July 

 26th winged females and larva> were foimd inside the folded corn 

 leaves and on young tassels. 



JManifestlv if corn has suffered severely from the attacks of this 

 pest, it is not advisahle. from the facts above stated, to use the same 

 field for corn the following year. 



Macrosif'Ji ii in trifolii. 



May 17: On corn (winged and wingless females) at St. An- 

 thony Park. 



Juh' 13: Su])posedl\- this s]~)ecies in oats at St. Anthony Park. 



Jul} 28: ( )n i)lantain adjoining a corn field at Olivia. One of 

 the larvae was attacked by mites. 



GENERAL REMEDIES FOR LICE ON GRAIN. 



As intimated in the special report and bidletin referred to above, 

 parasites keep grain plant lice in check in normal years, and owing to 

 climatic conditions here we need probably never fear serious loss from 

 these pests. Among their enemies are to be included certain pre- 

 daceous flies which lay their eggs among the colonies, these eggs hatch- 

 ing into hungry maggots, wliich consume large (juantities of lice. Then 

 too, the "iady bird" beetles, both the adults and young grubs eat an 

 enormous number, as do also the larvae of lace-winged flies, but the 

 hosts of tin\- winged ])arasitcs, although few in numl)er of species, are 

 the most useful instruments in aiding the farmer. From the fact that 

 the winter eggs of the above plant lice are found on various grasses 

 and on different volunteer grains near or in the stubble, it is evident 

 that keeping the edges of grain fields clean and free from such growths 

 would be an aid. The very usual practice of fall plowing of stubble 

 is, of course, of great value. 



This division of the E.xperiment Station has been working upon 

 insects affecting clover and alfalfa, the results of which will be pub- 

 lished later. 



