ANIMAL AND INSECT ENEMIES 215 



recommended for crows is often effective as a preventive. 

 Poison is also used. The ordinary method of poisoning 

 is to soak a quantity of corn in a strychnine solution and 

 plant this a few days ahead of the regular planting, in 

 parts of the field likely to be molested. Very often the 

 squirrels come mostly from adjacent pastures or meadows, 

 and a few rows of poisoned corn planted next to these will 

 be effective. 



INSECTS 



149. The larvse of several insects are very injurious 

 to corn under certain conditions. These may be grouped 

 as : (1) Insects injurious to the roots. (2) Insects injurious 

 to the young plant above ground. (3) Insects injurious 

 to some part of the mature plant, as ear or leaf. (4) 

 Insects that become abundant in cornfields only when 

 corn follows corn year after year, as the corn rootworm. 

 The remedy for this kind is rotation of corn with other 

 crops. (5) There is another group, which injures corn 

 only when it follows certain other crops. This includes 

 the wireworm, which is often injurious the first and second 

 years after grass sod. The grubworm is most often inju- 

 rious after a clover sod. (6) Certain migratory insects, 

 as the chinch bug, army worm, and stalk borer, which 

 come in mostly from adjacent fields. The most important 

 of these insects from an economic standpoint are here 

 given, together with suggestions for their control : — 



Cutworms 



Cutworms live on various kinds of grasses. The moths 

 lay their eggs in late summer. These eggs soon hatch 

 and the partially grown larvae live over winter in the 

 ground. They live on vegetation again the following year 



