34 OHIO EXPERIMENT STATION: BULLETIN 198 



SO as to remove part of the stubble, which may be burned. Badly 

 infested straw remaining unused should be burned by the'last of 

 March so as to prevent any adults escaping to growing fields. Straw 

 that has been well tramped by live stock and has been heated 

 several weeks by passing through the manure heap, is probably safe 

 enough to scatter over fields in spring, especially if they are distant 

 from the wheat field; but comparatively fresh straw that has under- 

 gone but little change since leaving the stack, although it has passed 

 through the manure heap, is too questionable to spread on ]a,nds 

 that are near wheat fields. Such green manure, if containing larvae 

 or pupae, should be left in the manure heap for a longer time. 



If young wheat looks very sickly in spring, examine it carefully 

 for indications of the Hessian Fly, Mayetiola destructor. The shining, 

 brownish pupae, closely resembling flaxseeds, may be found beneath 

 the culms at the bases of the plants. If they are very ' numerous in 

 April, and a large percentage of the plants died during the winter 

 from injury inflicted by them, it is sometimes best to plow the 

 infested field under deeply and plant to some other crop. 



CORN INSECTS. 

 APRIL-MAY. 



The Western Corn Root Worm, Diabrotica longicornis, is readily 

 controlled by rotation of crops. Do not follow corn with corn, and 

 do not plant corn in fields where the adult beetles were observed in 

 exceptional abundance on weeds and clover, the preceding year. 

 The beetle is about one-fifth of an inch in length and of a uniform 

 pale-green or grass-green color. A well fertilized soil and thorough 

 cultivation will do much to enable plants to outgrow damage to the 

 corn roots. 



Preventive measures for the Southern Corn Root Worm, Dia- 

 brotica i2-i>unctata, are the same as for the preceding species. Late 

 planting also helps protect against this species. Planting a sufficiently 

 large number of grains in a hill to feed the larvae and leave a good 

 stand besides is sometimes practiced. Most grains and vegetables 

 except beans and cucurbits, may be rotated with corn in bad] j 

 infested districts. The beetle is generally mistaken for a ladybug, 

 being of similar appearance, a trifle over one-fourth inch long, 

 yellowish green in color, the wing covers marked with 12 black spots. 



The Seed Corn Maggot, /Vo/wj'a/M5«ce2)s Zett, is more im- 

 portant as a vegetable insect than as a corn pest. (See page 80.) In 

 case it becomes destructive to corn, rotate the crops and use an 

 excess of seed. 



