No. t Department of agriculture. 2»7 



and toads that hibernate in such places. These are so beneficial 

 that one will effect injury to his own interests if he does not watch 

 and preserve them. 



By clean farming, we also mean the destruction of all kinds of 

 weeds and all plants that are out of place. Many insects feed on 

 all plants belonging to certain respective botanical families, as, 

 for example, the lice on the roots of the cabbage and cauliflower, 

 feeding also upon mustard. The Harlequin cabbage bug feeds 

 upon mustard as well as upon cabbage and cauliflower. The root 

 lice of these plants also feed upon weeds as well as upon cultivated 

 plants. Thus, it can be seen that if mustard, wild kale, etc., be 

 permitted to grow about the premises, even though the insects be 

 killed on the cultivated plants by cultivation and other means, they 

 will be continued from year to year upon weeds. Some insects feed 

 upon various kinds of weeds they do not have cultivated plants of 

 certain kinds upon which to feed. An example is the Colorado po- 

 tato beetle can live on the ground cherry. The destruction of weeds 

 not only insures better crops, but also greater freedom from insect 

 pests. The destruction or prevention of volunteer grain and plants 

 that are out of place, also means the destruction of insects which 

 they carry. If wheat be harvested after it becomes dead ripe, for 

 example, and the grains be scattered freely in the field, there is not 

 only loss from the wasted grain, but also growth of volunteer 

 plants in which the Hessian fly and other wheat-destroying insects 

 are almost sure to multiply. 



If old or neglected trees be permitted to grow around the prem- 

 ises without care, they support the insects that will constantly 

 menace and attack the desirable fruit trees. It is better to avoid 

 this by destroying all plants and trees that are not needed. 



This sub-heading of ^'clean farming" should include the destruc- 

 tion of dead trees and branches in the orchard, scraping trunks 

 and larger limbs to remove the bark, moss and lichens on trees, and 

 other operations which would prevent the insects from finding pro- 

 tection for pupation and hibernation. The codling moth, for ex- 

 ample, passes the winter in the larval stage within silken cocoons 

 beneath the scales of rough bark upon the trunks and larger 

 branches of trees. Not only many insects, but those germs or 

 spores that cause disease of plants, remain during the winter in 

 the moss and lichens on the rough bark, and if each of these en- 

 cumbrances be removed, the pests and diseases which they pro- 

 tect or harbor are likewise destroyed. The codling moth and other 

 insects pupate during the summer-time also beneath the bark of 

 trees, and their places of pupation should be destroyed in order to 

 prevent their finding safe retreats and expose them more readily 

 to the attacks of their enemies. In dead wood there may often be 



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