126 THE REPORT OF THE No. 19 



tliem of the grubs, for these bury themselves a foot or two below the surface 

 on the approach of frost." 



2. The farmer and fruit grower should know the injuries done hy the 

 principal injurious insects. 



Every crop is attacked at some part at some stage of its existence. For 

 example, the apple tree may be injured in its seedling stage by the leaf- 

 blister-mite on its leaves and the woolly aphis on its roots; the growing tree 

 by borers, plant lice, oyster-shell scale, San Jose scale ; and the fruit by the 

 codling worm and the railroad worm. The turnip is attacked by the flea- 

 beetle, during its young stage, and by the turnip aphis and others during 

 its growing period. The corn plant may be injured by the attacks of the 

 seed-corn maggot and wire worm on the seed in the ground, by the white 

 grub and wire worm on its roots, by the cut worm on its stems, by the corn 

 worm on its leaves, and by the grain moths on the stored grain. 



The farmer and fruit grower should be able to diagnose the causes of 

 the most serious insect troubles by the nature of the injuries inflicted, as 

 he would diagnose the cause of any ailment of his live stock. It is possible 

 after a careful study of the injuries to plants to identify the particular 

 insects that are causing the injuries, and to deal with them effectively. 

 Sometimes one has to rely entirely on the nature of the injuries for the identi- 

 fication of the insect. Cutworms, for example, work at night and lie concealed 

 in the day time. It is easy to distinguish the work of sucking insects from that 

 of biting insects, but this easy distinction is of prime importance in any 

 rational control of a pest. We sometimes hear of gardeners and fruit- 

 growers using paris green for the control of plant lice. A little elementary 

 knowledge of Entomology on their part would have saved them money, and 

 would have given them success instead of failure. 



3. The farmer and fruit grower should know the characters of the chief 

 orders of insects, and should be able to recognize the order to which any 

 common injurious form belongs from a glance at the larva or adult. There 

 are for all practical purposes but seven orders or divisions into which the 

 chief injurious insects may be placed. He should know what orders or 

 groups pass through a complete metamorphosis, — from e^g to larva, to 

 pupa, to adult, — during their life-history, and what orders have an incom- 

 plete metamorphosis, i.e., have the young somewhat like the adults; the 

 meaning of the terms cocoon, chrysalis, larva, pupa-, the difference between 

 a caterpillar and a grub; between a grub and a maggot; and of what order 

 each is characteristic ; what orders have biting mouth parts, and what 

 orders have sucking mouth parts. All this information is needful and 

 preliminary to an intelligent control of injurious insects. 



4. Every Farmer and Fruit Grower should know the Effect of Crop 

 Rotations, Good Cultivation, etc., i.e.. Cultural Methods in Insect Life. 



Cultural methods stand opposed here to artificial methods, such as 

 spraying. Where crop rotation is not practised the white grub and wire 

 worms sooner or later take possession of grass lands, and the cultivated 

 lands for a year or two after they are broken. But a good crop rotation, 

 where the crop is changed frequently makes it impossible for any insect to 

 pass through its life-stages without being seriously disturbed and its food 

 supply destroyed. Some rotations are preferable to others when certain 



