EXPERIMENT STATION BULLETINS. 



203 



tbey are often worse the second year after grass than they are the 

 first, most of them being full grown at that time. 



REMEDIES. 



In corn, the most noticeable injury is 

 to the seed after planting, though the 

 larvae also feed on the roots after the 

 corn is up. A long series of experiments 

 by Professors Comstock and Slingerland 

 of Cornell University, failed to show any 

 practicable method of treating the seed 

 so as to prevent injury by wire-worms. 

 They did show, however, that late fall 

 plowing killed many of the pupae and 

 adults by breaking open the earthen cells 

 in which they were. They failed also to 

 kill the wire-worms by any of the com- 

 mercial fertilizers or insecticides, unless 

 these were used in excessive quantities.* 



Professor S. A. Forbes, State Entomologist of Illinois, proposes a 

 rotation of crops in which clover shall always follow grass, and corn 

 shall always follow clover. Plow the grass in early fall, and sow clover, 

 either with oats, wheat or rye. Allow the clover to stand two year-s 

 and follow with corn.f 



On general principles it is well to use wood-ashes where obtainable, 

 because of their tonic effect on the plants. It is understood, of course, 

 that these practices are recommended for aggravated cases of wire-worm 

 infestation and not for regular use in the absence of the pest in dan- 

 gerous numbers. 



Fig. 53. — Click-beetle, adult of wire- 

 worm and larva, slightly enlarged. 



INSECTS AFFECTING THE ROOTS. 

 Corn- root Web-worm {Cr ambus zeelus). 



Although Michigan has, thus far, escaped injury from this pest, 

 Illinois and Ohio have not been so fortunate, and it would not be sur- 

 prising to find it at work in our State at any time. The method of 

 attack is quite characteristic of the pest so that it is not likely to be 

 confounded with anything else. The little caterpillar or larva, works 

 on the roots beneath the soil surface, and each larva is protected by a 

 small web of silken material. The adult moth is white, marked with 

 silver}' bands. It is about three-fourths of an inch in length. 



REMEDIAL. 



The natural food of the corn-root web-worm is grass, and for this 

 reason it is well to avoid planting corn on sod land in places where the 

 pest abounds. 



* Bui. 33, Cornell Univer.sity Experiment Station. 



t Rep. State Bd. Agr., 1893, p. 50, containing 18th Rep. State Ent. for 1891-2. 

 Insects Injurious to Indian Corn, Part I. 



A Monograph of 



