10 



FARMERS* BULLETIN 702. 



BACTERIAL DISEASES. 



The fact that when rabbits become excessively abundant in any 

 locality epizootic diseases often destroy them in large numbers has 

 led many people to expect that a micro-organism would be found 

 which would afford a ready means of rabbit control. The Biological 

 Survey receives many applications for such bacterial preparations. 

 In reply to all of them it has been necessary to state that thus far all 

 attempts to spread contagious disease artificially among wild rabbits 

 have failed to give practical results. 



PROTECTION OF CROPS FROM RABBITS. 



Complete extermination of rabbits in any part of the United 

 States is not desirable, even if possible. They should be reduced in 

 numbers only sufficiently to secure comparative safety to crops, and 

 before acth'e wholesale destruction of the animals is attempted the 

 possibility of crop protection by other means should be carefully 

 considered. In many cases one of these means would probably be 

 the more economical method. 



RABBIT-PROOF FENCES. 



When rabbits are abundant and the area to be protected is not too 

 great, a rabbit-proof fence may profitably be used. Woven- wire 

 netting is recommended for this purpose. This material is in general 

 use, not only against the rabbit pests of Australia and Europe, but 

 in our own country against both large and small rabbits. As our 

 species burrow less than the European rabbit the requirements for 

 rabbit proofing a fence here are not so great. Even the cottontails, 

 when driven by hunger, will dig under a fence, but this may be 

 prevented either by use of wire with close barbs in contact with the 

 ground or by plowing a furrow against the lower edge. A netting 

 of galvanized wire with lj-inch mesh and 2^ to 3 feet high is a suffi- 

 cient barrier against cottontails. Where snow is infrequent market 

 gardeners and nurserymen use a 2-foot fence, but in the North they 

 prefer to use a netting 3J feet wide, and to turn from 4 to 6 inches 

 of the lower edge flat and cover it with soil. Netting made of 

 No. 20 wire costs from 25 to 35 cents a rod. Heavier netting slightly 

 increases the cost, but adds to the durability of the fence. Where 

 lumber is cheap, a picket fence or one made of laths and wire is 

 practicable. When deep snows fall and drifts form, fences offer no 

 protection to crops against rabbits. 



TREE PROTECTION. 



WASHES. 



Many devices for protecting trees from rabbits have been recom- 

 mended, the majority of which are paints, smears, or washes sup- 

 posed to be distasteful to the animals. Many are not sufficiently 



